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KPABEP, CHARITY MAELEERA
PG/Ph.D/08/49025
DEVELOPMENT OF CAPACITY BUILDING MODULE FOR REFRIGERATION AND AIR-
CONDITIONING TECHNOLOGISTS IN SOUTH-SOUTH NIGERIA
FACULTY OF VOCATIONAL TEACHERS EDUCATION
DEPARTMENT OF INDUSTRIAL TECHNICAL EDUCATION
Ebere Omeje Digitally Signed by: Content manager’s Name
DN : CN = Webmaster’s name
O= University of Nigeria, Nsukka
OU = Innovation Centre
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DEVELOPMENT OF CAPACITY BUILDING MODULE FOR
REFRIGERATION AND AIR-CONDITIONING TECHNOLOGISTS IN SOUTH-SOUTH NIGERIA
By
KPABEP, CHARITY MAELEERA
PG/Ph.D/08/49025
DEPARTMENT OF INDUSTRIAL TECHNICAL EDUCATION
UNIVERSITY OF NIGERIA, NSUKKA
NOVEMBER, 2015
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TITLE PAGE
DEVELOPMENT OF CAPACITY BUILDING MODULE FOR REFRIGERATION AND AIR-CONDITIONING TECHNOLOGISTS
IN SOUTH-SOUTH NIGERIA
By
KPABEP, CHARITY MAELEERA
PG/Ph.D/08/49025
Being a Ph.D. Research seminar presented to the Faculty of Industrial Education in fulfilment of the Award of Doctor of Philosophy (Ph.D.)
Degree in Industrial Technical Education
UNIVERSITY OF NIGERIA, NSUKKA
NOVEMBER, 2015
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CERTIFICATION
Kpabep, Charity Maeleera a Postgraduate student in the Department of Industrial Technical
Education, with Registration Number PG/Ph.D/08/49025 has satisfactorily completed the
requirements for the Award of Doctor of Philosophy (Ph.D) in Industrial Technical Education.
The work embodied in this thesis is original and has not been submitted in part of full for any
Diploma or Degree of this or any other university.
…………………………………. …………………………….
Charity M. Kpabep Dr. T. C. Ogbuanya
Candidate Supervisor
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DEDICATION
This work is dedicated to NuBaridoo T. D. Taneh my sister and Leyah J. Kpabep my son.
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ACKNOWLEDGEMENT
Dr. T. C. Ogbuanya, you are a woman of value that has influenced my life and love for research. The foundation you have laid in me, will continue to reflect your academic excellence in my academic endeavor. Thank you for your diligence, perseverance and thoughtful critism given to my work to its final conclusion.
The researcher, acknowledge Prof P. Onwuasoanya, Prof C.A. Igbo, Dr. E.A. Anele, who read and contributed to my work at the proposal stage. I also acknowledge Prof E.O. Ede, Dr F.M. Onu, for their invaluable contributions.
Prof. B.B. Fakae and Prof. T. Sokari, it was under your influence and encouragement that the researcher pursued this programme. You both remain my models and mentors. I thank you both for your support.
Daso D.M you are my God given son. The support and understanding you rendered to me throughout the period of my research can never be forgotten. You sacrificed your comfort, time, for all that it takes for my success. Josiah Obakoma you always prove to be my shock absorber. You and Ofeno E. have always responded to my calls at any time that your support was needed. The researchers love and appreciates the relationship with all of you and may God reward you.
Engr. Ariyo D. Meeyima E. and Woobodo A, the researcher highly appreciates your acceptance and the assistance you offered to me in the course of my research, in contributing your professional experience.
Engr. Zukbee N, Mr. Friday Nue, Mr. Monsi, E. my colleagues, you all deserve special thanks for your understanding and encouragement during the course of my research. Also Nwachukwu Chika, Ibediugha Nnadozie, Mr. Chiorlu, D., Ifeanyi O. and Alhaji Shetima A., thank you all for pushing me through. I am comfortable from the first day I came in contact with you all. The researcher is grateful for working with you and for keeping my head up when it got too heavy for me to bear.
Special appreciation goes to my family members, my husband, Mr. Lekara L. Kpabep for accepting to bear my roles when i am away, giving me moral support. Nah, that is the name I know you for, but officially known and called NuBaridoo T.D. Taneh, from infancy you planted my academic pillars and you did not relent till date. Your prayers and several calls and motivation is highly appreciated, may Jehovah the God we both served from infancy continue to bless and keep us to live to our late father, Mr. Taneh D. Elobari expectations. Natura Taneh my mother, you were there despite your poor health supporting and encouraging me, being inquisitive to know the period of the completion of my programme. The researcher appreciate and thank God that you are alive to see this day. Anthony N. Taneh, Barr Saviour Taneh and all
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the children in the house. The researcher thank you all for the different roles played by each and every one.
Kalenebari D. Kpabep, you are my jewel, you were just five years old when the researcher started the programme but you were so fast to be the one that supported when there was need to carry out some computer operations may Jehovah keep making you to grow and become whatever God has in store for you. Bari-agara Precious, you also served as my assistant when weighed down with typing. Thank you my daughters.
Above all researcher gives the greatest thanks and praise to my God, Jehovah, for his love, care, protection and the preservation of my life to see this day despite all the stormy periods. You demonstrated that you are the provider of knowledge, wisdom and life.
Kpabep, Charity Maeleera
University of Nigeria,
Nsukka.
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TABLE OF CONTENTS TITLE PAGE i APPROVAL PAGE ii CERTIFICATION iii DEDICATION iv ACKNOWLEDGEMENTS v TABLE OF CONTENTS vii LIST OF TABLES x LIST OF FIGURES xi ABSTRACT xii
CHAPTER ONE: INTRODUCTION 1
Background of the Study 1
Statement of the Problem 9
Purpose of the Study 10
Significance of the Study 11
Research Question 13
Hypothesis 14
Scope of the Study 14
CHAPTER TWO: REVIEW OF RELATED LITERATURE 15
Conceptual Framework 16
Refrigeration and Air-Condition Technology 19
Polytechnic Education 21
Capacity Building 22
Development of Module 23
Need for a Module 32
Objectives of Capacity Building Module 37
Content of Capacity Building Modules 43
Training Facilities in Capacity Building Modules 74
Teaching Strategies in Capacity Building Modules 80
Evaluation Techniques in Capacity Building Modules 88
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Theoretical Framework 95
Taba’s model of Curriculum Development 95
Skinner’s Operant Conditioning 97
Career development theory 97
Related Empirical studies 98
Summary of Review of Related Literature 103
CHAPTER THREE: METHODOLOGY 105
Design of the Study 105
Area of the Study 106
Population for the Study 107
Sample and Sampling Technique 107
Identification of Goal for Capacity Building Module 107
Development of Instrument 108
Validation of the instrument 109
Need Assessment 111
Development of Module 112
CHAPTER FOUR: PRESENTATION AND ANALYSIS OF DATA
Research Question 1 114
Research Question 2: 115
Research Question 3: 123
Research Question 4: 125
Research Question 5: 127
Major Findings of the Study 129
Discussion of Findings 138
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CHAPTER FIVE: SUMMARY, CONCLUSION AND RECOMMENDATIO N 147
Restatement of the Problem 147
Summary of the Procedures used for the Study 148
Major Findings of the Study 149
Implication of the Study 150
Conclusion 152
Recommendation 153
Suggestion for Further Studies 154
REFERENCES 155
APPENDICES 165
Appendix I: Letter to Validate of Modules 166
Appendix II: Request for Respondent Participation 167
Appendix III: Questionnaire for the Development of Capacity Building 168
Appendix IV: Capacity Building Module 204
Appendix V: Refrigeration and Air -Conditioning \Psychomotive Ratings Scale 212
Appendix VI: Self Check Test 216
Appendix VII: Try-out of Modules Analysis 217
Appendix VIII: Result of Analysis of Need Assessment Using SPSS 226
Appendix IX: Reliability of Instrument 230
Appendix X: NBTE Curriculum Refrigeration and Air-Conditioning 231
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LIST OF TABLES
Table Page
1: Mean Response of Teachers, Technologists and Technicians on the objectives of capacity building modules for technologists in refrigeration and air-conditioning. 114
2: Mean Responses of Teachers, Technologists and Technicians on Leak Detection content 115
3: Mean Responses of Teachers, Technologists and Technicians on Evacuation of Contaminants content. 117
4: Mean Responses of Teachers, Technologists and Technicians on Trouble-shooting Electrical Panel content 118
5: Mean Responses of Teachers, Technologists and Technicians on Recovery/Recycling content 119
6: Mean Responses of Teachers, Technologists and Technicians on Retrofitting content 120
7: Mean Responses of Teachers, Technologists and Technicians on Trouble-shooting Electrical Panel content, 121
8: Mean Responses of Teachers, Technologists and Technicians on Facilities 123
9: Mean Responses of Teachers on teaching strategies 125 10: Mean Responses of Teachers on Evaluation Techniques 127 11: Hypothesis Testing 128
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LIST OF FIGURES
Figure Page
Figure 1: Schematic View of Conceptual Framework, Kpabep (2014) 18 Figure 2: Dick and Cary’s Model 29 Figure 3: Kemp’s Instructional Design Model 30 Figure 4: Taba’s Curriculum Model 96
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ABSTRACT
The purpose of the study was to develop capacity building modules for technologists in refrigeration and air-conditioning in south-south Nigeria. Specifically, the study determined the Objectives of the modules for the capacity building of refrigeration and air-condition technologists. Content of the modules for capacity building of refrigeration and air-condition technologists. Teaching strategies for capacity building of refrigeration and air-condition technologists. Training facilities for capacity building of refrigeration and air-condition technologists. Evaluation techniques for capacity building of refrigeration and air-condition technologist. Develop modules for capacity building of refrigeration and air-conditioning technologists. Try-out to validate the developed modules. Research and development design was used. Five research question and one Hypotheses was used. The total population of the study was 118 which comprised 14 teachers of refrigeration and air-conditioning, 34 technologist, 45 technicians, and 25 students of mechanical engineering used for try-out. There was no sampling and purposive sampling technique was used. Two sets of instrument namely; questionnaire for the development of capacity building module for technologist in refrigeration and air-conditioning (QDCBMTRA) and Refrigeration and Air-conditioning Psychomotive Rating Scale (RAPRS) were subjected to validation by two specialist in Refrigeration and Air-conditioning industry and two lecturers in the university. Cronbach alpha was used to establish the reliability of the instrument which yielded 0.89 and Kendall concordance correlation was used to determine the reliability of (RAPRS) Data obtained from the administration of the instrument was analyzed using cut-off point of 3.5 for decision making. The information obtained was used for the development of the capacity building modules. The developed modules were tried- out on 25 final year students of mechanical engineering in Federal Polytechnic, Offa. There was initial and final rating. The scores obtained was analyzed using ANCOVA at 0.05 level of significance to test the hypothesis The result obtained revealed that there was significance difference 0.05 level. The study recommended that National Board for Technical Education should set up curriculum review committee that will use the module content for modification of refrigeration and air-conditioning practical content. Federal Government should re-train polytechnics teachers and graduates of polytechnics for capacity building in refrigeration and air- conditioning using developed modules.
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CHAPTER ONE
INTRODUCTION
Background of the Study
Refrigeration and air-conditioning is a vital technology needed for industrial
development. The importance of refrigeration and air-conditioning is evident in domestic,
commercial and industrial application. Fruits and vegetables are stored at a low temperature after
harvest with the aid of refrigerator. Also beverages, as well as staple foods are commonly
preserved using refrigerator. Air-conditioning has enhanced business and industrial productivity
while adding to human comfort. Rajput (2010) stated that application of refrigeration and air-
conditioning are found in ice making, transportation, industrial air-conditioning, comfort air-
conditioning, chemical and related industries, medical, processed food products and beverages,
oil refining and synthetic rubber manufacturing, manufacturing and treatment of metals and
freezing of products.
Refrigeration and air-conditioning systems are the equipment that are employed for
producing low temperature. According to Rajput (2010), refrigeration is the science of producing
and maintaining temperature below that of the surrounding atmosphere, and air-conditioning is
the science of producing specified condition of air within required space of building. William
and William (2008) described refrigeration as the process of removing heat from a place where it
is not needed and removing that heat to a place where it creates little or no difference; while air-
conditioning is described as the process of maintaining comfort condition in a defined area.
Arora (2000) in his view, described refrigeration as the extraction of heat from a space at a
temperature lower than the surrounding temperature, while air-conditioning is a system of
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maintaining temperature, humidity, air purity and air movement of a given space. In other
words, refrigeration is the process of heat removal from products and transferring the heat to
outside boundary by a cooling medium known as refrigerant through the principle of energy
conversion, while air-conditioning as a process, is the filtration of air, regulation of air
movement, reducing and controlling of temperature and humidity through energy conversion.
Refrigeration and Air-conditioning processes are accomplished through the working
fluid in the Piping of the Refrigerators and Air-conditioners. This working fluid is known as
refrigerants. Desai (2000) defined refrigerant as the medium of heat transfer within a
refrigerating system through extraction of heat by evaporating at low temperature and pressure
and gives up heat after condensing at a higher temperature and pressure. The commonly used
type of refrigerants are those categorized as Hydrochlorofluorocarbons and Chlorofluorocarbon
in refrigerators and air-conditioners. These refrigerants according to Cox (1992) were
discovered to contain chlorine content which, when emitted into the atmosphere, reacts with
ozone molecule, causing ozone depletion. Ozone, according to Cox, is the band of gas at the
upper atmosphere of the earth that is vital to the functioning of life on earth. Significant
increase in ultraviolet radiation as a result of ozone depletion causes reduction in immune
system, skin cancer, deforestation and destruction of the ecosystem (Thornhill, 2007).
Ozone depleting potential is contained in majority of refrigerators and air-conditioners
used in homes, hospitals, transportation systems, and industries in South-South. Continual
utilization of these plants without adequate maintenance skills causes frequent break down
.Poor skills during repairing, results to emission of ozone depleting refrigerants into the
atmosphere as was observed by the researcher. Skills such as leak detection, evacuation of
contaminants, trouble-shooting electrical panel, recovery/recycling, retrofitting and
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commissioning are expected from technologists by the industries. Technologists in the context
of the study are graduates of polytechnics who have completed their programme in Higher
National Diploma. The curriculum by National Board for Technical Education (NBTE, 2001)
for Mechanical Engineering Power/Plant option stressed that at completion of the programme,
the technologist should be able to install, maintain, and diagnose refrigeration and air-
conditioning plants.
National Board for Technical Education, the major stakeholder in Polytechnic education
in Nigeria was set up by the Federal Government to oversee the activities of Polytechnics and to
ensure quality technical and vocational education. Conversely, the curriculum of Polytechnics
for Mechanical Engineering, Refrigeration and Air-conditioning courses, by NBTE has not
included new skill in leak detection, evacuation of contaminants, trouble-shooting electrical
panel, recovery/recycling, retrofitting and commissioning in the curriculum for Higher National
Diploma in mechanical engineering used for training prospective technologists that specializes
in power/plant or building services. There appears to be gap between the training acquired by
technologists and the skills required for the new technologies in refrigeration and air-
conditioning, as indicated in the curriculum of NBTE (2001), (See Appendix X, Page 231).
The Preliminary study conducted by the researcher (Ogbuanya & Kpabep 2013) to find
out the needed skills by refrigeration and air-conditioning technologists, working in industries in
the south-south, Nigeria, further revealed that there is gap in the skills acquired by the
technologists. Findings of the study showed that, technologists need skills in leak detection,
evacuation of contaminants, trouble-shooting electrical panel, recovering/recycling, retrofitting,
and commissioning. These skills needed by technologists are necessary because, 80% of
refrigeration and air-conditioning equipment, including domestic, commercial and industrial type
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used in Nigeria still contain Ozone depleting refrigerants. The technologist skills, however, need
to be upgraded through capacity building module.
Capacity building, according to Alert and Dickson (2009), is the assistance which is
provided to individual that need to develop certain skills or competence for general upgrading of
performance ability. Boerne (2005), defines capacity building as community development that
focuses on enhancing the technological and self-help capacities of individuals. Capacity building
in the context of this study is the retraining that will be given to refrigeration and air-
conditioning technologists who might need to upgrade their skills in leak detection, evacuation,
trouble-shooting recovery/recycling, retrofitting and commissioning of refrigeration and air-
conditioning to the international standards of practice for reduction of emission of ozone
depleting refrigerant in order to be employable. These new skills need to be developed into
modules.
The act of creating a new thing is said to be development. According to Marzona (1998),
development is the outlining or articulating of the necessary skills that will help trainers to teach
and learners to master the objectives of training. Development in this study involves diagnoses of
needs, determination of objectives, content, training facilities, teaching strategies and evaluation
techniques before articulating all into modules that will aid trainers to train and learners to learn
skills needed of refrigeration and air-conditioning technologists for environmental protection and
employability.
Module is a curriculum material, a teaching kit that outlines all the necessary components
of teaching procedures in sequential steps and presents the total curriculum at a glance in a grid.
It provides opportunity for individuals to study at their pace, at a given time. Mangal and Mangal
(2012) define module as a set of learning activities intended to facilitate the student’s
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achievement on an objective or set of objectives. The author further explains that modules
contain a set of objectives, content, evaluation and learning experience and that it also presents
matters in sequential steps. The researcher will develop capacity building modules, using Taba’s
model of curriculum development (1962). Taba’s model follows sequential steps, such as,
diagnosis of needs, formulation of objectives, selection of content, organization of content,
selection of both learning experience and determination of what to evaluate. Therefore, the
modules in this study will consist of objectives, content, training facilities, teaching strategies
and evaluation techniques.
Objective of an instruction is the foundation for teaching, learning and evaluation.
Objective is the first step in establishing the validity of any instructional method and evaluation.
Objective according to Merger (1997) provides the structure that helps educators to organizing
and also communicate their instructional intents. Objectives direct the teaching and learning
strategies and it also forms the basis for developing measuring instruments. Objectives of this
study therefore is to develop a capacity building module in refrigeration and air-conditioning
such that will enable the technologists to carry out leak detection, evacuation, trouble-shoot
electrical panel, recover/recycle, retrofit and commission refrigeration and air-condition without
emitting ozone depleting refrigerants into the atmosphere. These identified skills will form the
content of the modules.
The content of the module will serve as a means of achieving the stated objectives.
Through the content, the trainee will learn the expected skills. Oteh and Akuma (2010) affirms
that content is the subject matter of what is taught and learned in school. The content of this
module will consist of leak detection, evacuation of contaminant, recovery/recycling, retrofitting,
troubleshooting and commissioning.
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Leak detection is one of the major technologies in the management of ozone depleting
refrigerants. The new technology in leak detection, according UNEP (1999) includes adding glo-
leak tracer into the compressor, for tracing refrigerant leaks with an ultraviolet lamp available
only for mineral and polyester lubricant. Testing on regular basis with specialized leak detectors
was recently produced to detect Hydro fluorocarbon (HFC) refrigerants along with the use of
Halide torch. Detection of leakage according to British Refrigeration Association (2007) is seen
as the manual procedures carried out by a qualified technician, to check refrigeration systems in
order to identify possible leaks in tubes, joints and connections. The Association recommended
that, use of electronic refrigerant detector, ultra-violent lamp and halide torch are the main
methods in management of ozone depleting refrigerants. When a leak is detected, good practice
requires that the system is evacuated before charging.
Evacuation of contaminant is usually carried out on systems having presence of moisture
or gases that do not liquefy in the system. Roberto (2010) affirmed that, evacuation is the most
effective way to eliminate contaminant from a system. The use of high vacuum pump creates
vacuum deep enough to evaporate and remove moisture. Evacuation is achieved by connecting
the system to a vacuum pump and allowing the vacuum pump to pump continuously for some
time, while a deep vacuum is drawn in the system. Evacuation is carried out when replacing a
circuit component like condenser, compressor, evaporator, drier and when the system no longer
has refrigerant due to leakage. The new technology requires that the system refrigerant is
recovered before evacuation.
Recovery according to United Nation Environmental Programme (UNEP) (1999) is the
removal of refrigerant in any condition from the system with the aid of recovering/recycling
machine. This process takes place when the system is to be serviced or when refrigerant needs to
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be charged into the system due to leakage. If the recovered refrigerant is found to be acidic and
the life span of the system is still long, the system is expected to be retrofitted with alternative
refrigerant that has no ozone depleting potentials.
Retrofitting according to Association of Heating Refrigeration Air-conditioning
Engineers (ASHRAE) (2010) is the replacement of corresponding alternative refrigerant with an
existing ozone friendly refrigerant. Retrofitting involves changing parts that are compatible with
new refrigerant. If conversion does not require such measure modification, the alternative
refrigerant is called drop-in refrigerant or retro-fill process. Retrofitting from ozone depleting
substance system to an ozone friendly system, usually requires a thorough investigation of the
system and such investigations involves troubleshooting the electrical panel .
Trouble-shooting is defined by Andrew, Carl and Alfred (2000) as the process of
analyzing the problems of the unit. Troubleshooting refrigeration and air-condition unit usually
involves fault finding on the entire system. Trouble –shooting electrical panel in this study is
limited to industrial unit. The electrical panel of the industrial units carries components such as
capacitor, relay, overload, high and low pressure control, fuse and wiring terminals to the
compressor (Refrigeration and Air-Conditioning Advance Training Institute, 2007). Trouble-
shooting skills on an electrical panel of industrial refrigerators and air-conditioners is a vital skill
that is highly needed from technologists for sustainability of commissioned plants.
Commissioning according to Architectural Service Department (2007) is usually carried
out on refrigeration and air-conditioning equipment in order to verify the proper functioning of
the equipment after installation, for ensuring that the performance of the equipment meets the
specified design, through a series of tests and adjustments with a recorded performance data of
the whole installation as guide for official operation and maintenance. The Association further
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explains that, the information on the base line, gives information that confirms when the
equipment components are in satisfactory and safe condition before start-up. Commissioning is a
vital task that forms the content of capacity building modules. The content of an instruction
cannot be transmitted to the learner without a good interactive session between the trainer and
trainee with adequate training facilities.
Training facilities are the relevant tools and equipment that enhances teaching and
learning relevant skills within the content of modules. Davis (2011) confirmed that adequate
training facilities enhances skill development of students in technical occupation. Vikoo (2003)
explained that instructional material is anything that a teacher can profitably employ to facilitate
teaching and learning. Therefore modules for capacity building in refrigeration and air-condition
will contain equipment, tools and materials that represent the industrial set-up. For the training
facilities to effectively train, adequate teaching strategy is necessary.
Teaching strategy is the plan or specific way employed by teachers or trainers to facilitate
learning and achieve learning goals. Mangal and Mangal (2012) defined teaching strategies as a
generalized plan for a lesson which include structure, desired learning behaviours in terms of
goals of instruction and an outline of designed procedure necessary to implement the strategy.
Vikoo (2003) defined teaching strategies as delivery system, which includes different teaching
methods, utilized by teachers to achieve the set objectives. Effective implementation of teaching
strategies involves selection of good training materials, teaching method and evaluation
techniques in order to realise the set behavioral objectives. The success of the teaching strategies
employed can only be confirmed through effective evaluation techniques.
Evaluation techniques are various means that are utilized to measure the extent to which
learning has taken place. Mangal and Mangal (2012) stated that evaluation techniques are ways
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or means to measure and assess the extent to which the desired behavioral changes have taken
place in the learner. The various techniques include, practical tests, written test examination that
consist of essays and objectives, checklists, attitude scales, observations, discussions, project
work and oral tests. Oteh and Akuma (2010) affirms that evaluation entail compilation of data,
analyses and inter-relation of the accumulated data from the lesson content, method used in the
delivery, process of presentation, time taken to present the lessons, facilities available for the
lessons, the atmosphere surrounding the presentation of the lessons and the evidence that the
lesson have taken place. Evaluation of capacity building in refrigeration and air-conditioning involves
various activities designed to determine the extent to which objective of the capacity building modules
have been achieved. These evaluation techniques includes, observations, written tests, practical tasks,
project, evaluation questionnaires, checklists, use of matching items and basic line criteria for
performance acceptance.
Therefore, there is need to develop capacity building modules for technologists in
refrigeration and air-conditioning in the South-South. The capacity building module when
developed and utilize, will enhance skills of technologists in leak detection. This will reduce
emission ozone depleting refrigerants. Skill in trouble-shoot electrical panel and evacuation of
contaminants responsible for compressor burn-out, refrigerant wastage and emission of ozone
depleting refrigerants that occurs during compressor replacement. Skills for recovery/ recycling
of refrigerants, retrofitting for conversion of ozone depleting refrigerant system to ozone friendly
system when the expected life of existing system is still large are needed.
Statement of the problem
Application of refrigeration and air-conditioning is vital for industrial development in ice
making, transportation, industrial air-conditioning, comfort air-conditioning, chemical and
related industries, medical, processed food products and beverages, oil refining and synthetic
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rubber manufacturing, manufacturing and treatment of metals and freezing of products in
industries in South-South, Nigeria. Continual utilization of these plants without adequate
maintenance skills causes frequent break down .Poor skills during repairing results to emission
of ozone depleting refrigerants into the atmosphere as was observed by the researcher.
Individuals and companies still having these systems need to retain these equipment.
Skills for leak detection, evacuation of contaminant trouble-shooting electrical panel,
recovery/recycling retrofitting and commissioning are the vital skills that are internationally
needed from technologists, to enable them install, repair, and convert, if possible, the ozone
depleting refrigerant systems to ozone friendly systems without venting ozone depleting
refrigerants into the atmosphere.
Preliminary study (Ogbuanya & Kpabep, 2013) carried out by the researcher revealed
that technologists in the South- South, do not acquire these skills and the industries expect
technologists to acquire these skills. The possible reason why the technologists are not yet
acquiring these skills is because these vital skills are not included in the curriculum of the
National Board for Technical Education that is used for training the technologists in
Polytechnics. (See Appendix X pg 230). The problem of this study therefore, is that there is no
module in leak detection, evacuation of contaminants, trouble - shooting electrical panel,
recovering/recycling, retrofitting alternative refrigerants, and commissioning for the capacity
building of technologists in refrigeration and air- conditioning.
Purpose of the Study
The main purpose of this study is to develop capacity building modules in refrigeration
and air-conditioning for technologists in south-south, Nigeria.
Specifically, the study will determine the following:
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1. Objectives of the modules for the capacity building of refrigeration and air-conditioning
technologists.
2. Content of the modules for capacity building of refrigeration and air-conditioning
technologists.
3. Teaching strategies for capacity building of refrigeration and air-condition technologists.
4. Training facilities for capacity building of refrigeration and air-condition technologists.
5. Evaluation techniques for capacity building of refrigeration and air-condition technologist.
6. Develop modules for capacity building of refrigeration and air-conditioning technologists.
7. Try-out developed modules
Significance of the Study
The capacity building module for refrigeration and air-conditioning technologists will be
beneficial to Polytechnics, Industrial training centres industries, technical skill instructional
developers, National Association of Refrigeration and Air-Conditioning Practitioners, National
Board for Technical Education, Ministry of Environment, Ozone Planning Implementation Unit
and the entire society if the developed module is adopted and utilized.
Polytechnics will benefit from the developed capacity building module, if the module is
adopted into the practical content for refrigeration and air- conditioning curriculum of
polytechnic use for training Higher National Diploma. The polytechnic graduates will acquire
the needed skills by the industries for employability and environmental protection.
National Board for technical education during curriculum modification will enrich the
Mechanical Engineering curriculum to international standard. Other bodies such as National
Board for Business and Technical Education in charge of technical colleges, National Directorate
for Employment in charge of training unemployed youth, industrial training units in industries
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will benefit when the module is adopted for up-grading skills of refrigeration technologists,
craftsmen and technicians. This will bring about good refrigeration and air-conditioning practice
in Nigeria if the developed module is adopted.
Technical skills instructional developers will benefit by adopting the content, objectives,
sequential task layout, evaluation techniques and teaching strategies in the module as pattern for
subsequent modules to be developed for skill development.
Industrial training centres will benefit if the module is adopted for training. Especially
adult trainees and youths (apprentices), will be able to select content that apply to their special
needs. The skills acquired by the youths trained with the module will earn them internationally
employability skills. This will reduce unemployment in the country. Also when these youths are
employed, parents will benefit, because it will reduce the burden of caring for the needs of these
youths. Older parents will also be taking care of by the employed youths.
Instructors of refrigeration and air-conditioning will benefit from the module by using it
for self-development. This will enhance their practical skills in management of ozone depleting
refrigerants. The practical skills acquired, will equip them to be able to impart the expected skills
to the trainees. The module also will provide guide to individuals (entrepreneurs) who might
wish to set up training centres for capacity building in refrigeration and air-conditioning.
Ozone Management Implementation Unit in Nigeria, in partnership with the Federal
Ministry of environment will benefit from the module if adopted for the training of refrigeration
and air-conditioning practitioners in management of ozone depleting refrigerants. It is also
possible that other neighboring developing countries will also benefit by utilizing the module for
training refrigeration and air-conditioning practitioners for good practice and management of
ozone depleting refrigerants.
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Industries will benefit when those trained by the module is employed in the industries and
when the training unit utilizes the module to train those already employed, because the mastering
skills acquired by these technologists trained with the module in the industries will cause less
breaking down of plants, less refrigerant wastage, less emission of refrigerants. Hence there will
be increase in productivity. The increase in productivity will affect all sectors of economy
including Pharmaceutical industries, Agricultural industries, Communication industries, Hospital
theatres, Fabric industries, Oil tool producing industries, Oil producing industries ,fertilizer
industries, transport industries, churches, restaurants, stores, breweries, schools, offices,
residential buildings and the total comfort of man that needs refrigeration and air-conditioning
utilization for optimal productivity.
The entire society will benefit from the developed module .The included skills in the
module when adequately practiced, will bring about good practices that will prevent emission of
ozone depleting refrigerants into the atmosphere. Reduction of ozone depletion will reduce the
rate of global warming that causes eye cataract; reduce immune system deforestation, destruction
of ecosystem and rate of mortality of man from malaria. Hence the environment will be protected
and there will be improve health for all.
Research Questions
The following research questions will be answered by the study.
1. What are the objectives of the capacity building module for refrigeration and air-
conditioning technologists?
2. What are the contents for capacity building of refrigeration and air-conditioning
technologists of the modules?
3. What are the facilities required for the capacity building of refrigeration and air-
conditioning technologists?
14
4. What teaching strategy could be employed for the proper implementation of the capacity
building module
5. What are the evaluation techniques that could be used to asses technologists in the
capacity building?
Hypothesis
There is no significant difference in the mean performance of technologists before and
after training with the developed modules
Scope of the Study
The study is delimited to the development, validation and try-out of capacity building
modules for refrigeration and air-conditioning technologists in South-South, Nigeria. This study
will diagnose the needed skills in refrigeration and air-conditioning, determine the objectives,
content, teaching strategies, training facilities and evaluation techniques to be packaged into
module.
15
CHAPTER TWO
REVIEW OF RELATED LITERATURE
Introduction
The review of related literature was organized under the following sub headings:
Conceptual Framework
• Refrigeration and Air-Condition Technology
• Polytechnic Education
• Capacity Building
• Development of Module
• Need for a Module
• Objectives of Capacity Building Modules in Refrigeration and Air-Conditioning
• Content of Capacity Building Modules in Refrigeration and Air-Conditioning
• Training Facilities in Capacity Building Modules in Refrigeration and Air-Conditioning
• Teaching Strategies in Capacity Building Modules In Refrigeration and Air-Conditioning
• Evaluation Techniques in Capacity Building Modules in Refrigeration and Air-
Conditioning
Theoretical Framework
• Skinner’s Learning Theory on Instructional Development
• Taba’s model of Curriculum Development
• Self-Concept Theory Career Development by Servickas
15
16
Related Empirical studies
Summary of Review Related Literature
Conceptual Framework
Conceptual framework is the narrative form or schematic representative of the main
factors that are involved in the study of development of capacity building module for
technologists in refrigeration and air-condition. Eboh (2009) defined conceptual framework as a
statement or narrative description or illustration of the causative mechanisms and relationship
deducible from the research problems. The relationship that exists among the concept of the
study is refrigeration and air-conditioning, technologists, polytechnic education, development of
module, capacity building
Refrigeration and air-conditioning technology has, today, taken a new dimension due to
the impact of ozone depleting refrigerants on the atmosphere. The new technology creates
additional tasks on the technologists, stake holders in the refrigeration and air-conditioning
industries, in order to achieve emission reduction and phase-out ozone depletion. Retraining is
required of those who work on refrigeration and air-condition plants, and are expected to cover
topics such as recovery/recycling, retrofitting, leak detection, evacuation and commissioning
(Manual for Refrigerator Servicing Technician, 2015).
Technologists are specialists devoted to the application of existing technologies within a
field of engineering. The work of the technologist is normally focused on the portion of the
technological spectrum closest to product improvement, manufacturing and engineering
operational function. (Electronic communications ABET-www.abet.org).The technologists in this
study are products of polytechnics that have acquired Higher National Diploma in Mechanical
engineering, with specialty in building services or power/plant. Polytechnic is a post-secondary
17
technical institution of higher learning, created primarily to provide a variety of intermediate and
higher level technologists (Okpeoda, 2007). The technologists who are products of polytechnics
are expected to acquire the new skills needed for managing and phasing-out ozone depleting
refrigerants. These new skills were developed into modules.
Development of module, according to Marzona (1998) is the outlining or articulating of
the necessary skills or activities that will assist trainers to teach the learner to master the training
objectives. Module is a self-learning package dealing with one specific matter. Module is
structured in such a way that the learner and trainer can identify the objectives he/she wants to
achieve, select the appropriate training facilities, follow a learning sequence by selecting from
variety of teaching strategies presented and evaluating his/her own achievements. The
component of the capacity building module will include of content, objectives, facilities,
teaching strategies, and evaluation techniques. The capacity building module when utilized will
enhance the skills of technologists in leak detection, evacuation, trouble-shooting electrical panel
and commissioning of refrigeration and air-condition plants. The manifestation of mastering
skills by technologists will contribute to the environmental protection and employable skills of
technologists in refrigeration and air-conditioning.
18
Figure 1. Schematic View of Conceptual Framework, Kpabep (2015)
DEFICIENCY NEED ANALYSIS
STAKE HOLDERS
(technologists, practitioners in industry)
SKILL NEEDS BY TECHNOLOGISTS
LEAK DETECTION
EVACUATION OF CONTAMINANT
RECOVERING & RECYCLING
RETROFITTING
TROUBLE SHOOTING ELECTRIC PANEL
COMMISSIONING
CAPACITY BUILDING
REFRIGERATION AND AIR-
CONDITIONING TECHNOLOGISTS
DEVELOPMENT OF CAPACITY BUILDING MODULES COMPONENT
TRY OUT OF MODULES DRAFT
MODULES FINAL
DEVELOPED
UTILIZATION OF CAPACITY BUILDING MODULE BY REFRIGERATION & AIR-CONDITIONING TECHNOLOGISTS
GOOD PRACTICES BY TECHNOLOGISTS
WITHOUT EMISSION OF OZONE DEPLETING
REFRIGERANTS
REDUCTION OF EMISSION OF OZONE DEPLETING REFRIGERAN TS AND ENVIRONMENTAL PROTECTION
IDENTIFICATION OF THEORIES
19
The figure drawn above represents the schema of capacity building module. The schema
identifies skills in refrigeration and air-conditioning for technologists from stake holders in the
industries through deficiency need analysis. The identified skills includes leak detection ,
evacuation of contaminants, trouble-shooting electrical panel , recovery/recycling , retrofitting ,
and commission. The identified skills are developed into capacity building modules for
technologists in refrigeration and air-conditioning that will bring about mastery skills for
employability and environmental protection.
Refrigeration and Air-conditioning Technology
Refrigeration and air-conditioning is one of the skilled courses offered in polytechnics.
The general objectives of refrigeration and air-condition is to train skilled technologists that will
be able to diagnose, repair and install refrigeration and air-condition plants (NBTE, 2001).
UNEP (2010) recommended that the skills of polytechnic students and teachers in refrigeration
and air-condition should be improved in order to develop good practices that will prevent
emission of Ozone depleting refrigerants during repairs, installations and commission. The first
refrigerator, hand-operated compressor machine was developed by Perkins in 1834. The field of
refrigeration was further developed when Du Pont put in the market a family of new refrigerants
known as fluoro-chloro derivatives of methane, ethane, popularly known as fluorocarbons or
CFCs in 1920. Recent findings revealed that fluorocarbons contain chlorine atoms that are
responsible for the depletion of Ozone layer in the upper atmosphere (Arora, 2012).
Refrigerant recycling requirement of section 608 of the clean Air Act of 1990 require
service practices that maximize recovery of Ozone-depleting substances both
Hydrochlorofluorocarbons (HCFCs) and Chlorofluorocarbons (CFC) and their blends when
servicing and disposing air-conditioners and refrigerators, set certification requirements for
20
refrigerant recovery and recycling equipment, technicians and refrigerants reclaimers. The Air
Act 608 further stated that Environmental Protection Agency (EPA) has established a technician
certification program for persons (technicians) who are qualified to perform maintenance, repair
or disposal that could not reasonably expect the discharge of refrigerants into the atmosphere
(Environmental Protection Agency, 2015).
James (2008) recommended that the technicians working with refrigerants must obtain
appropriate training and certification, since the basic training is not adequate; periodic retraining
is required of them. James also laid emphasis on the fact that training is the best line of defence
in refrigerant safety.
While regulatory compliance obliges the certification of all personnel working with
refrigerants, the aspect of certification is only the first step. James continued by saying that all
employees who work with or close to refrigerants must receive comprehensive training in all
work processes. Bouma (2011) reported that, internally, refrigerant conservation is an attempt to
prolong the life span of refrigerating and air-conditioning plants through recovering, recycling of
refrigerants. Bouma further affirmed that many countries have acknowledged that refrigerants
emission can be greatly reduced by having effective recovery, recycling and reclamation
programmes.
Ozone Programme Implementation Unit (OPIAMU) (2006) stated that OPIAMU will
need to establish training programme known as Good Practices in Refrigeration and air-condition
in Nigeria, that will enhance the skills of almost 28,000 practitioners, comprising technicians,
artisans, craftsmen and technologists that are involved in recovery, recycling of refrigerants that
are normally vented during repair and maintenance activities, decommissioning and retrofitting
of CFC based equipment. Capacity build modules for refrigeration and air-condition will support
21
the plans of OPIAMU for retraining technologists, technicians and all who install repair and
carry out maintenance activities.
Polytechnic Education in Nigeria
Polytechnic is a post-secondary technical institution of higher learning, created primarily
to offer a variety of intermediate and higher level technologists, according to (Okpeodua 2007).
Polytechnic education is needed for acquisition of technological values, requisite knowledge,
desirable work, attitudes, development and adaptation of essential techniques relevant to
satisfying the middle-level manpower requirement for Nigeria. Eze (1990) affirmed that
polytechnic education was established under section 6, sub-section 49, Decree 33 of 1979 to be
the main vehicle for technological advancement. Adegbile (1993) explained that the word
‘Polytechnic’ comes from the Greek words ‘poly’, meaning many, and ‘techno’, meaning Arts.
This means that a polytechnic is the teaching of many arts and science.
Polytechnic education is where technological knowledge and skills are achieved for
direct application to the solution to societal problems. Longe commission on Higher Education in
Nigeria (1992) acknowledged the goals and main objectives of polytechnic education as
teaching, research, and public service similar to universities but with more emphasis on the
application and development of skills. Aigbeque and Idogho (2010) affirmed that polytechnics is
being given the mandate of ensuring quality training for capacity building in technology for
competitive job market. Stakeholders such as industries, institutions and National Board for
Technical Education have a role to play in ensuring that right capacity building programmes are
provided to meet the nation’s demand of large stock of trained technologists.
National Policy on Education (2004) stated that polytechnics shall have their specific
goals in providing the technical knowledge and skills necessary for agricultural, industrial,
22
commercial, and economic developments in Nigeria, as follows: Give exposure on professional
studies in the technologies, Give training and impact the necessary skills for the production of
technicians, technologists and other experienced personnel who will be enterprising and self-
reliant and able to train people who can make use of their scientific knowledge to solve
environmental problems for the human comfort.
Capacity Building
Capacity building according to Alerts and Dickson (2007) is the assistance provided by
entities, who have a need to develop certain skills or competence for the general upgrading of
performance ability. Boerne (2005) defined capacity building as a community development that
focuses on enhancing the technological and self-help capacities for individual. Effective capacity
building according to United Nations Development Programme (UNDP) (2010) take the
following steps: (1) involve the stake holders, that are directly affected by the situations; (2)
Assess capacity needs and assets through participation with stake holders, thereby, allowing the
capacity builders to see what areas require additional training(4) formulating a capacity
development response through re-assessment. This should include evaluative indicator to
measure the effectiveness of initiated programs. Finally, United Nation Development Programme
indicated that evaluation of capacity building for re-training that promotes accountability
measurement should be based on change in individual institution’s performance.
The role of capacity building in this context, is therefore, to harness the capabilities
within the network of individual demands, and enhance industrial interaction to better the
process of the technologists of refrigeration and air-condition, to acquire industrial skills through
a developed re-training module. Yusup (2009) confirms that module is recommended for
improved learning and teaching and that it is one in a series of training package designed for
23
working with graduate technologists with disabilities in a correctional setting. Capacity building
in refrigeration and air-condition will improve the technological skills in refrigeration and air-
condition on the effect of refrigerants to the environment, reduction of ozone depleting
refrigerants emission in the environment, trouble- shooting electrical panel, leak detection,
evacuation of contaminants, retrofitting, recovering/recycling, commissioning, safety and
maintenance, and provide employment opportunity.
Development of Module
Development of module according to Marzona quoted earlier, is the outing or articulation
of the necessary skills or activities that will assist trainers to teach the learners to master the
training objectives, with a sequence of learning activities and provision for evaluation. Marzona
continued that the components of modules include medicated instructional technologies,
reference materials, demonstration, team activities, visual aids and system of feedback.
Therefore, in developing the module, the skills for technologists in refrigeration and air-
conditioning that enables them repair, install and commission refrigerators and air-conditioners
that are vital in the industries which enable them repair without emitting ozone depleting
refrigerant to the atmosphere will be articulated.
Most modules contain all the materials needed to achieve the objectives of the module.
Frequently, the term, package is used in connection with self- instructional material such as
modules and this reflects the idea of a close self-contained unit. Modules are usually produced
in a standardized series. They can be transported and reproduced in a way that would be
impossible in the conventional approach. This does not imply that all modules should stand
entirely alone. Some modules can be designed for use with a standard textbook or with a
laboratory or workshop equipped with apparatus or machinery. Instructions can be built into a
24
module, requesting students to undertake specified reading, complete certain practical task. In
addition, a single module in a series can sometimes assume study of previous modules or lead to
subsequent study of other modules. So while modules are essentially self-contained, they are not
totally closed-in on themselves. They also provide bridges to other forms of learning and to other
modules (Silkwood, 2000).
The student-using module is given the opportunity to conduct a self-paced study with in-
built instant-replay. Furthermore modular packages can be sequenced in a variety of patterns to
build unique courses of study, catering for students with different interests and needs. A basic
assumption made in the development of any self-paced learning package is that learning is a
process which must be undertaken by the learner. Responsibility for learning shifts from the
teacher to the students. Self-instructional systems such as modules are student-centered. This
underlying assumption has important implications for the arrangement of subject matter, types of
media used and allowances made for individual differences. The assumption that students control
their own learning must be regarded as the basic rational underlying any system of self-
instruction, but it is also important to note that the principles of learning employed in self-
instruction are derived from theories of learning, which can be applied to a wide variety of
learning situations. Students learn to learn through modular instruction of which the skills can be
transferred to most other systems of teaching and learning. This is one of the most powerful
arguments for introducing students to modules (Gagne and Briggs 1992).
In a typical class there are many differences between learners. It is usually impossible for
a teacher to meet all the needs of each individual student at the same time so he/she must follow
a course, which will present the best options for the greatest number. Some individual
differences which have a marked influence on rate of learning including differences in
25
intellectual ability, differences in academic background, and differences in manner or style of
learning. In regard to the last point it is becoming increasingly obvious to educators that people
differ greatly in the way they think-some prefer, for example, to see things as a whole while
others would rather approach an issue or area of knowledge more analytically. Another aspect is
that some students learn more quickly by oral methods in contrast to others who learn better by
visual methods. Self-instructional modules allow the rate of learning to be adjusted to suit the
needs of each individual student. The slow learner is able to repeat any part of the package,
which was found difficult, fast learners, can move more quickly provided they can demonstrate
achievement and this free them from keeping to the average pace of a group (Greene and Hicks,
in Silkwood 2000).
Greene and Hicks further said that students learn more efficiently when they have a clear
directive about what is it they should lean. Clearly stated objectives have a key role for those
who write modules, for the teacher who uses them and for the students studying them. A well
stated objective gives the module writer criteria for the selection of subject matter, leaning
activities and test items. He/she knows exactly what the learners is expected to achieve and so
can design all aspects of the module to meet each objective. The teacher gains insight into the
suitability of the module for his/her students and can closely monitor progress towards the
achievement of the objectives. For the students, objectives exactly describe what is expected and
provide goals to be mastered. Each student’s learning activities becomes goal-oriented. Modular
packages therefore, take full advantage of the benefits of a clear statement of objectives. The
more closely associated in time and space the elements to be learnt, the more effective will be the
total learning. Modules not only bring together elements such as practical experiences,
26
theoretical material and information from different media but they ensure that subject matter is
brought into close association with all relevant and related concepts.
In construction of a module close attention is given to the most appropriate sequencing of
meaningful material. Basic ideas upon which subsequent information is dependent are presented
first. This is in line with the views by educators such as Gagne and Mager (1982) in John (2006)
who claimed that instruction is most effective when information is sequenced as a hierarchy of
ideas. Simpler concepts lead to more complex ideas. In a module each terminal objective
requires its own hierarchy. It would cater for individual differences in the backgrounds of
learners by letting each student reach at an appropriate point in the hierarchy. Other educators
would prefer to respond to individual differences by allowing each student to generate his/her
own learning sequence, relating what needs to be known to what is already known. According to
this view, if the sequence of learning events does not suit student, then with appropriately
designed self-instruction he/she is free to alter the sequence to suit specific needs. The process of
planning and conversion of a conventionally taught subject to a fully modular approach involves
a total rethinking of the curriculum. It is necessary to review again the purpose, aims/objectives,
contents, sequencing and methods. That is the whole procedure of curriculum development needs
to be rethought and reprocessed. The following steps are recommended. The first step is
determined which subject is to be modularized and this usually requires an application of the
deficiency model of needs analysis. The next step is to analyze the subject into either (or both)
competencies or conceptual units by means of task and concept analysis respectively.
In designing, selection and sequence of the modular topics is very necessary. John (2006)
affirmed that the principle of structuring and sequencing subject matter within a given module
apply to the problems of dividing up the content of a total course into a sequence of modules and
27
so only a few specific points will be made at this stage. Basic decisions must be made about each
of the following issues in terms of the most effective pattern for the achievement of the
objectives of the course as a whole: Can each module stand alone or must the modules be
arranged in a definite learning sequence to achieve cumulative outcomes? If there is cumulative
gain what is the optional leaning sequence for the topics, skills and values? Can all the content of
the course needed to achieve its objectives fit into the number of modules consistent with the
allowed course for as a whole? If not what are the alternatives? Where should the main points of
consolidation occur and how frequently? In preparation of Curriculum Grid, the final step in the
design of modular course is to prepare what can be taken as curriculum grid as indicated by the
researcher below.
The grid Lists the modules in groups or categories and shows the recommended learning
sequence between and within categories. This provides an overview of the course as a whole for
purpose of production and as a subsequent guide to users. Two types of grid are possible, or mix
of both types. The grid can be based on job analysis or concept analysis. In the former duties can
be shown on the vertical axis and task on the horizontal axis. In the latter, then it would show
areas of the discipline vertically and the topics horizontally. Each cell in the grid represents a
module. Each module deals with one major topics or group of related topics (John 2006).
Module design according to Silkwood (2000) and John (2006) involves identification of
module components and utilization of the components in ensuring the objectives of the module.
Identification of module components starts with deficiency needs analysis of task. They want
further to explain deficiency needs analysis as a gap between “what is” and “what should be”, or
expressed in another way, as the gap between what is observed and what is desired. As a simple
example, teachers note that students consistently have difficulty with a particular chapter of a
28
book and so decide that the need is for a more effective learning resource for that topic. An
analysis of need using the deficiency model involves the following steps: Identification and
interpretation of the optimal results, outputs or products expected of a particular situation,
organization, program or institution, Investigation and interpretation of the present outputs and
Identification of the “gaps” between present and optimally desired outputs.
Dick and Carey cited in Yusuf (2009) identified Dick and Carey system approach model
addresses instruction to be a sum of isolated parts. The model addresses instruction as a
complete system, concentrating on the interrelationship between content, context, learning and
instruction. The components of the system Approach model known as Dick and Carey model are
as follows: Identify instructional goals: goal statement defines a skill, knowledge or attitude
(SKA) that a learner will be expected to obtain, conduct instructional analysis: identify what a
learner must recall, and identify what the learner must be able to do to perform a particular task,
analyze learners and contexts: recognize overall characteristics of the target audience comprising
prior skills, prior experience, and basic demographic, identify features directly related to the skill
about to be taught, and carry out analysis of the performance and learning settings, write
performance objective: objectives comprises of a description of the behavior, the condition and
criteria. The component of an objective that defines the conditions that will be used to judge the
learner’s performance, Develop assessment instruments: Purpose of entry behavior testing,
purpose of practice item/practical problems, purpose of pretesting, develop instructional strategy,
pre-instructional activities, learner participation, content presentation, assessment, develop and
select instructional materials, design and conduct formative evaluation of instructor. Designers
try to identify areas of the instructional material that requires improvement, revise instruction.
To detect poor test items and identify poor instruction, Design and conduct summative.
29
The eight components of Dick and Carey model is adopted in the study by considering
the need analysis of the skills needed by the technologists, objectives, content, teaching
strategies, training facilities and evaluation techniques for the development of module for
refrigeration and air-conditioning technologists and the module will also adopt the formative
evaluation model.
Figure 2. Dick and Cary’s Model
Kemp’s instructional Design model adopts a wide assessment; the oval shape of his
model conveys that the design and development procedure is a continuous cycle that requires
continuous planning, development, design and assessment to guarantee effective instruction.
The model is mainly suitable for developing instructional programs that merger technology and
pedagogy and content to deliver effective, inclusive (reliable) and effective learning. The nine
key elements of Kemp’s model are: Pinpoint instructional problems and specify goal for
designing an instructional program, examine learner characteristics that should receive
consideration during design process, identify subject content and analyze task components
connected to stated purposes and goals, indicate instructional objectives for the learner, build
Fig. 1
30
content within each instructional unit for logical learning, plan instructional strategies to enable
each of the learners to master the objectives, design the instructional message and delivery, select
resources to sustain instruction and learning activities, create evaluation instruments to assess
objectives (Kemp Instructional Design Model,2012)
Kemp’s instructional model is adopted in the study by considering all the processes, more
especially the project management and support services that will enable the researcher to ensure
that after designing the instruction message known to be the module for refrigeration and air-
conditioning, the module will be applied and being sustained and managed by the researcher to
ensure that the discharge of ozone depleting refrigerant into the atmosphere is reduce to the
minimal though the practice of the technologists trained by the module but the model does not
consider formative evaluation as propounded by Dick and Carey hence for capacity building
module for refrigeration and air-conditioning technologists to be standardized, the module will
be evaluated through research questionnaire validation, reliability, module validation and trial-
test of the modules.
Figure 3: Kpabep’s Development of Module Model
1 2
Determination of Goal
Development of instrument
Development of module
Validation of instrument
Need Assessment
3
4
5
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The model is useful in the design of modular program to help with the selection of a subject to be
modularized or to identify special areas of need within a subject to established priorities for
developing specific modules Acelajado (2005) explained that another approach to the
determination of need is to undertake a job analysis. Job analysis particular job into duties, each
of which in turn is seen to consist of a number of tasks. Each task can itself be divided into a
number of tasks elements. In job analysis the tasks are referred to as competencies. In
determining the needs of a curriculum, which aims to prepare a student for a particular job. It is-
clear that the determination of competencies is very important in modular design therefore it is
usually helpful to investigate what students will be able to do when in employment and to plan
modules to ensure on - job competency.
Module designer in. particular need to do this for two main reasons. Firstly, modules
generally combine both theoretical and practical aspects and therefore both job analysis
(competencies) and subject analysis (topic) are important. Secondly, not all subjects need to be
full modularized and therefore it is especially important to apply the deficiency model to
determine just which need of particular course would be best served by development of specific
modules. Modular approach in teaching is a recent development and may be considered as a
modification of an improvement upon the famous concept of programmed instruction. This
individual is based upon the well establish and universally recognized phenomenon of
individual differences among the learners which necessitates the planning for and adoption of
most appropriate teaching techniques. Different researchers and experts defined module in
different ways. John (2006) defined module as a unit of work in a way of instruction that is
essentially self-contained and a process of teaching that is based on the idea of building up skills
and knowledge in discrete units.
32
Need for Module
Module is an individualized self-instructional package, which helps the students to
achieve a wide range of objectives at their own pace. It is more flexible approach that has been
adopted in order to meet the specific requirement of students or to satisfy the special need of
particular students e.g. the students studying on their own pace at a distance from the parent
institution. John (2006) and Silkwood (2000) both defined module as an organized collection of
learning experiences assembled in order to achieve a specific group of related objectives or a
self–contained section of a course or programmed of instruction and that module is a set of
learning opportunities organized around a well-defined topic, which contains the following:
Elements of instruction, Specific objectives, Teaching / learning activities, and Evaluation.
Different levels and categories of learners need different syllabi, according to their needs.
However, some inputs may be common amongst some groups. It may, therefore, be useful to
develop self–contained units of curricula. These are called modules, and these are like mini–
curricula and are developed separately for each of the interrelated tasks or topics Silkwood
(2000). A module is a set of learning opportunities that organized a well – defined topic which
contains the element of instruction, teaching learning activities, specific objectives, and
evaluation using criterion measures (UNESCO, 2000).
Module according to Acelajado (2005) is a self-contained and self-sufficient instructional
unit. A module should have detailed instructions specifying clearly the instructional objectives of
the unit, the list of learning activities to achieve these objectives and also the evaluation
techniques. The learning activities would normally be self-instructional; the organization of the
activities should be clearly specified. Always emphasis should be on the learners participating to
the maximum and the teacher’s interference to the minimum.
33
Modular teaching is one of the most widespread and recognized teaching learning
techniques in United States, Australia arid many other Western counties including Asian region.
Modular teaching is used in almost all subjects like, natural sciences, particularly in biology and
medical education and even in social sciences. Various kinds of courses are being taught
through modules Silkwood (2000). The concept of “module” is specifically linked to the idea of
a flexible language curriculum, which should provide all those related with education (primarily
teachers and learners, but also parents and administrators, as well as society at large) with a
concept to establish clear and realistic language learning objectives. (Kandarp, 2013)
Yusup (2009) stated the benefits of the modular system to include the following: The
students are able to increase skills in line with their sets of abilities and interest, An intensive
flow of information linked to real world that is outside of the school is provided, Individual
teaching is possible, It becomes flexible for the student to use his/her personal out-of-school
experience and knowledge related to the subject in class, The student can join the teaching
program at any time and Transition between different programs is possible.
Mark (2002) compared modular approach and traditional approach by saying that using
modules demands not only curricular changes but changes in conventional teaching procedures.
Traditionally, elementary chemistry courses are taught in a lecture-lab format; students listen and
take notes during the instructor’s lecture, then partake in smaller laboratory experience that
allows students to practice using equipment while conducting what are basically verification
laboratories. However, to encourage the kind of intellectual engagement that characterizes
modular-based classes, instructors must do more than to lecture. Thus, instructors use teaching
methods that foster what is referred to as active learning – which needs more than just listening
34
(e.g., writing, discussing, questioning), but also partaking in higher-order cognitive activities
such as synthesis and evaluation.
The modular system allows for a different learning process. General principles through a
whole subject area can be laid out first. Specific details are also introduced as required to build a
working knowledge and ability in the subject area. Thus the student moves “down” into more
details as they are needed, but these are always in the context of the objectives and applications.
This learning procedure has proven to be highly motivational for students because they link the
basic information to the overall purposes for attending the course. (UOFN, 2011).
Active teaching models help the students with their progress as an individual and
increasing their clear, creative, wise thinking and building social commitments and skills. In
other words, teaching active models create self-control, self-study and self-making in students
and teachers. Generally, applying new models and active teaching methods can cause into
meaningful and deep learning in the students (Khorshidi, 2008).
Active learning is the outcome of teaching method in which students are involved
actively. Active teaching methods engage the students in the groups with distinct roles for each
student and the task is done in the group. Active teaching method rises class learning knowledge
and memorization (Keyser, 2000).
In modular teaching method, teaching objectives divide into partial objectives (Modules)
and for each of limited objective a working desk is used. In this method the teacher is not the
only source of knowledge and the learner is not dependent to the teacher. Learning environment
is student-centered and the teacher can play active role in giving information to the learner and
guide each learners according to their need (Aqazadeh, 2005).
35
Adibnia, (2010) affirmed that in modular method after defining the content of teaching
and the main objectives and determination of the capability of presenting content based on the
method the following steps are taken: The main goals are divided into functional partial goals,
Good functional activities and conditions are designed in relation to each of the above goals.
These conditions are called activity station or task desk, Students groups are arranged in a way to
the activities as periodical, to have the opportunity to handle all the activities, Class time is
divided into equal parts. In each part, each group of students are engaged with an activity and by
finishing time, each groups goes to the next task desk and begin a new activity and The groups
with the opportunity they have for combining the results of activity stations, by reading the
textbook achieve the main goals of curriculum.
Adibnia, further identified advantages of modular method to include the following group
activities are short, purposeful and along with the following aims; in modular method, each task
desk is dedicated to a different task. Thus there is no need to have same equipments for all the
groups and fewer amenities are provided for all, Modular method saves time for doing activity.
Optimized use of time makes teaching efficient, in modular method; the diversity of tests and
activities attracts the attention and increases educational attractiveness and in modular method,
being familiar with new subjects directs the learners to the activities beyond texts books.
Module encourages autonomy in learning and the use of modules places the user in far
greater control of his/her own learning. There is a major shift of focus from the teacher to the
student. The climate becomes more learner-centered. This is an important step towards
independence and prides the individual work of the student. Modules can help system, maintain
satisfactory minimum standard since they package materials in a standardized form that is the
same for all. Because modules are largely self- instructional, they can be distributed from a
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central point to all learners who immediately perceive the basic objectives to be attained and
work independently towards achieving these objectives (Silkwood, 2000; John, 2006).
Modules can be used very flexible they can provide not only basic elements of a
programme but also materials for enrichment or extra learning and also units for remedial
training. The latter role is especially important in cases where students may enter a course with
uneven standard of preparation rather than delaying a whole class for the sake of a few students,
remedial modules can be used to allow the individual concerned to close gapes in basic
knowledge on skills (Davies, 2011).
Silkwood (2000) and John (2005) said that the modules have an important role in staff
development at least in two respects. Firstly, they provide teachers with well-designed carefully
structured lesson materials and so serve as examples of effective instructional design. Secondly,
they can be specifically written for the teachers. With regard to the latter aspect, package can be
produced on such aspects as instructional planning, teaching-learning methods, and student
evaluation and so on. Such packages can be developed as part of staff development programme.
Because modules are largely self-instructional and the learner proceeds in small steps. It is
possible to proceeds each step in practical work by appropriate theoretical explanations. It is also
possible to consolidate theory and practice by relating each element to the other work
convincingly and coherently than in conventional teaching.
Different groups of students may require different treatment in teaching -leaning process.
It is difficult to cater for the needs of different sub groups in a conventional classroom but self -
instructional packages (modules) can easily solve this problem by providing a compulsory core
and a series of optional or alternative strands within the same course. Because the modules are
self - paced, they do cater to an extent for individual differences in the learner abilities, interests
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and degrees of application, A basic core of essential modules can be provided for all optional
extra enrichment units cm be available to keen students, remedial modules can be used by those
needing some essential prior knowledge or skill and alternative units can be provided for
students who may have difficulty with the main stream approach.
Most courses have points or topics of special importance on difficulty, which need to be
mastered for the understanding of the programme as a whole. While it may not be possible to
fully modularize all parts of a particular course specific modules can be readily produced for
certain critical or traditionally difficult areas for ensuring complete mastery of these topics. In
this way failure or dropout rates are minimized and a firm basis for future learning is assured.
Modules are ideal for distance leaching since they are readily transportable. They can be tailored
to the requirements of a wide range of subject areas by building in films, tapes and other non-
print media. Modules are useful not only for the distance education of trainees but also for staff
development at a distance. Sets of modules can be used by teaching staff of widely separated
institutions to ensure attainment of necessary teaching competencies (Acelajodo 2005).
Objective of Capacity Building Module in Refrigeration and Air-Conditioning
The way to effective technological instruction starts with a well concerned and
constructed objectives. The objectives are the first point for develop an effective and successful
module. Objective is a way in which an instructor can inform others of what the learner intend
for the students to achieve. Objectives should be well-defined after identifying the context of
learning. Ketaki, Odesma and Srividya (2012), acknowledge the structure of an objective can
have three features, performance-what the learner should be able to do, conditions-the
circumstances under which the learner should able to get it done and criterion-how well must it
be done.
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Differences in the use of language when it comes to writing general and specific
objective is very important. When phrasing specific objectives, verbs must be used which gives
very precise meanings. Suitable examples would be words like solving, writing, identifying,
selecting, operating, calculating, drawing. General objectives would use words such as know,
understand, recognize, and appreciate. The following guidelines are expected to be suitable for
writing general and specific objectives for a module. These include: writing a general objective
beginning the statement with a verb know, understand, recognize and appreciate, State each
general objective in a term of student’s performance but not observable behavioral performance
at this stage. Do not write the statement from the point of view of the teacher, but from that of
the learner, State each general objective in a way, which shows an overall terminal-learning
outcome of the student, State the general level of expected learning outcome in the general
objective, Indicate under each general objective all the exact behavioral outcomes to emerge
from studying that particular section at the module. Remember that these will offer direct
evidence that the general objectives have been achieved, In writing specific objectives start with
a verb that indicates measurable and observable behavior e.g. describe, relate, list, calculate and
so on, Note that while complex objectives like critical thinking or appreciation are difficult to
specify in behavior terms they must not be omitted just because of that, If necessary and
appropriate, specify the circumstances in which the behavior is to be observed and standards to
be anticipated, Revise the list of specific and general objectives as required to ensure that they
cover the entire area of proposed learning and Sequence the general objectives, and each set of
precise objectives within them in such a manner that the learning results of one becomes the pie-
requisite for achieving the learning outcome of the next.
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In writing modules, just as the development of any form of learning resource, it is
important that the objectives cover all groups of achievements appropriate for the students and
for the subject matter involved. A useful planning device to ensure adequate coverage is to apply
the classification system developed by Bloom and his colleagues. Three domains of Bloom’s
taxonomy are: The cognitive domain, objectives linked to knowledge, the affective domain,
objectives concerned with interest attitudes and values, the psychomotor domain, objectives
linked to practical skills and Subsequently, Bloom and his associates, devised a classification
system or taxonomy of objectives, based on the three domains. Within each “domain” five or six
main categories were established and arranged in rank order from the simplest to more complex.
This domain relates to objectives connected with knowledge and intellectual skills. The
six levels from the easiest to most complex are as follow: Knowledge: Recalling specific and
information about methods and also general items of information, processes and patterns,
Comprehension: recognizing items of information in settings to but different from those in
which they were first encountered, Application: explaining previously unseen data or events by
applying knowledge from other sensations, Analysis: Breaking down blocks of information
into elements for the purpose of clarification, Synthesis: Building information from previously
separate units of knowledge and Evaluation: Making judgments about the value of information,
materials or methods for given purposes.
The domain relates to objectives concerned with interest, attitudes, and values. The five
levels of the affective domain from simplest to the most complex are as follows: Receiving:
Sensitivity to certain stimuli and willingness to receive or attend to them, Responding:
Involvement in a subject or actively or event to the extent of seeking it out, working with it or
engaging in it, Valuing: Commitment to a conviction in certain goals, ideas or beliefs,
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Organization: Organization of values into a system, awareness or relevance of relation,
organization between appropriate values and the establishment of dominant personal values and
Characterization by a value complex: Integration of beliefs, ideas and attitudes into a total
philosophy or worldview.
This domain is concerned with manipulative skills involving muscular or motor
responses requiring neuromuscular coordination. The five levels of the psychomotor domain
from the simplest to most complex are as follows: Imitation: Copy of an observed act but lacking
neuromuscular coordination, Manipulation: Copy of an observed act usually following
instruction, displaying some neuromuscular coordination, Precision: Performance of a physical
act with accuracy, proportion and exactness, Articulation: Competent performance of a physical
act involving coordination of a series of other acts and Naturalization: Reutilization of a physical
act to the extent that it becomes an automatic spontaneous and ultimately subconscious response
according to Bloom cited Silkwood (2000).
Bloom continued by saying that the posttest must be designed to check on mastery of the
specific objectives providing evidence that the general objectives have been attained, each
objective must be tested by a corresponding item on the pastiest. As each specific objective is
written, it is strongly recommended that a draft of the relevant item on the posttest be prepared at
the same time. According to Block (1987), this has three advantages:
In the first place writing the relevant posttest items for a given objective helps in wording
the objective. If it is difficult to write a test question then the behavior implied by the objective
may not have been clearly and explicitly expressed. This suggests that further revision of the
statement of objective is needed. The second advantage is that writing an early draft of all
questions for the posttest provides a second check on overall educational outcomes. It may be
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that something of key importance has been left out and if so the list of objectives can be further
revised. Thirdly, an early draft of the posttest moves the planning of the module considerably
ahead. The following checklist may be used to evaluate draft of objectives. They also provide a
summary of some of the key ideas. They are as follows: Does the general objective indicate an
appropriate outcome for the instructional unit? Does the general objective include desired
outcomes as knowledge, skills, attitudes etc.? Are the overall objectives attainable taking into
account the ability of students, time constraints, facilities, etc.? Is the overall objective relevant
to the module’s aims? Does the overall objective begin with a verb? E.g. know, understand,
etc., is the overall objective clear, concise and well defined? Is the specific objective relevant
to the general objective? Does each specific objective begin with an action verb to denote the
desired terminal behavior of the students? Is the specific objectives stated in terms of student
performance rather than teacher performance? Does each specific objective communicate only
one learning outcome? Have the specific objectives been arranged in a logical sequence? And
does the list of objectives reflect what is intended by the corresponding general objective?
In conclusion, writing carefully prescribed objectives for a module is a critical step in
design. The objective must be stated at general and specific levels in performance term. Where
necessary, the conditions, under which the individual is expected to, perform and the standard of
acceptable performance should be indicated. Objectives, however, should be kept free of trivial.
They should not be broken down into minute details. This would result in unduly long learning
sequence in the module. Objectives should he carefully checked to see that they adequately they
present suitable levels of the three domains of Bloom’s taxonomy.
The following list provides practical hints on writing statements of general objectives.
They are: Carefully review the purpose and aims of the course in general and of this module in
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particular. Pay particular attention to the likely entry behavior of the students concerned,
Objectives should not be stated in terms of a teacher performance or requirement; Statements of
contents are not objectives. What should be emphasized in what the learner has to do? Objective
should not be stated in terms of the learning process, the product of instruction or the leaning
outcome should be stressed. Words like gains, acquire and develop generally indicate that focus
is on the leaning process rather than on the outcome of the learning and so should be avoided in
writing general objective. Such terms are satisfactory however, in statements of aims. Avoid
more than one type of learning outcome in each general objective. While general objectives are
concerned with learning outcomes they are the outcomes that cannot be discussed directly. These
outcomes must be defined more precisely by the specific objectives. Therefore, in writing
general objectives, use the words like, understand, know, appreciate, recognize, show concern
for, evaluate, and demonstrate. When the List of general objectives has been completed, check
that it is comprehensive. Make sure all relevant domains and levels of the Bloom taxonomy are
represented. Arrange the general objectives in a logical teaching sequence.
For each general objective identify all the specific behavior that would be necessary to
effectively demonstrate achievement of that general objective, List each set of specific behavior
in logical teaching sequence, Convert each behavior into a statement of a specific objective. It
helps if you preface each list with a phrase such as “After studying this unit section you should
be able to this is in the case of general objectives, it is not sufficient just to define the content
area. The expected talk behavior of the learner in relation to the content should also be described,
as in the case of the general objectives, each specific objective should focus on only one learning
outcome, Use words and phrase which indicate overt actions, which can be directly observed.
Avoid verbs which reflect, internal behavior or mental activities like know, understand,
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appreciate, learn. Try to think of the behavior not only in terms of the type of activity, which will
facilitate the behavior. That is provided for variety by using different action words to
differentiate between objectives within a given level of a particular domain and Make sure all
appropriate levels of such domains of Bloom’s taxonomy have been included.
Wes (2004) affirmed that writing objectives for complex instruction has a framework
known as short- term objectives. The short –term objectives has two functions, it breaks goals
into smaller units for instructions and it assesses students’ progress towards meeting goals.
Short-term objectives can also be used as benchmarks to measure progress towards goals against
a time frame. In using short-term objectives as benchmark, they are assigned times when it is
anticipated to achieve its goals at a specified period.
Content of Capacity Building Module
Content of instruction according to Oteh and Akuma (2010) is the subject matter or what
is taught and learned in school. The content of the module will serve as a vehicle for the
development of skills in refrigeration and air-conditioning.
Leak Detection on Refrigeration and Air-conditioning Plant
Tightness testing for leakage in Refrigeration and Air conditioners system is taken as one
of the code practice in refrigeration and air conditioning industry. The British refrigeration
association (2010) in its code of practice stress the need for those installing, designing,
commissioning, servicing and maintaining Refrigeration and Air-conditioning system to take all
reasonable steps to minimize leakage potential. Section 34 of Act (Duty of care) in the British
code of practice places a precise responsibility on personnel to have control over any
refrigeration system to ensure that anyone undertaking task on the system does not allow
refrigerant to escape. Article 3, emphasized that operators of stationary refrigeration, air
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conditioning equipment shall prevent leakage of refrigerant and as soon as possible repair any
detected leak. It went further t state that was a proper functioning leakage detection system is in
place; the frequency of the leakage inspections shall be halved.
The British refrigeration association further gave reasons for leak detection to be carried
out especially on hydro fluorocarbon and chlorofluorocarbon refrigerants to be; Environmental
impact – many refrigerants damage the ozone layer and also contribute to global warming.
Higher running cost: running cost will escalate refrigerant leakage reduces efficiency. This has
consequence on the environment in that the lost refrigerant has an impact, but the extra energy
consumption of the system leads to more carbon dioxide emission from power station, Increased
servicing cost – these may include call out charges, tiding and remedying the leak, replacement
refrigerant, possibly even the replacement of a burn out compressor and consequent system
cleaning and Heating and safety hazard – dependent on the refrigerant and the site of the leakage,
if it were in a confine space exposure level could potentially be surpassed leading to suffocation
if sufficient loss and displacement of air occurs.
The leak detection regulation by the British Regulation Association recommends that
with portable refrigerant detectors, different refrigerant detectors exist and suitability of the
utilization and type of refrigerant should be verified with the system manufacturer. Different
types of portable leak detector are available which includes Electronic refrigerant detector. These
detectors are sensitive to leakage rate as small as possible. The selection of those device must be
made to ensure that their suitability for the refrigerant within the system. Another type of
refrigerant leak detector is the ultraviolet indicator fluid.
The ultraviolet indicator fluid is a refrigerant detection system that have been developed
using a fluorescent or a colored dye which is added into the system and is distributed throughout
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the system with the lubricant and it indicates leak by emission of leaking refrigerant. When the
refrigerant evaporates, the dye remains at the site of the leak. With the aid of the ultraviolent
lamp, the leakage is made visible. The effectiveness of this method of leakage detection will
significantly reduce in system with sufficient oil separation devices. In order for this method to
be effective, it is important that any emitted fluid is thoroughly cleansed from the components
once the area of leakage has been identified and the leakage remedied. The proprietary bubble
solution also known as soap solution is another method of refrigerant leak detection.
The proprietary bubble or soap solution possibly the simplest and the most sensitive of
method of tightness testing for leakage using weak soap solution by applying it to the area being
tested. It is recommended that the use of this method be considered in conjunction with the use
of portable electronic refrigerant detection devices.
The British refrigeration’s association recommends that in order for a task of refrigerant
loss detection and system pressure testing to be carried out safely and effectively. It is important
that minimum level of individual competence and training are identified therefore the study is
meant to develop a retraining module on leak detection for refrigeration and air-conditioning
technologists.
VTECH (2010) affirmed that in the refrigeration industry, component and system must
be leak tested to ensure that refrigerant leakages are below specified limits and that the three
basic functions of leak testing are; To determine if there is leakage or not, To measure leak rate
and to identify leak location. Although there are many methods of leak detection, there is no
simple techniques that fit every situation. Each test method is suitable for s specific leak rate
forms and technologies. VTECH further define leak as an unintended cracks, hole, or porosity in
an enveloping wall or joint which must contain or exclude different fluids and allowing the
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escape of closed medium. VTECH identified critical leak sports in closed system are usually
gasket, connections, welding and brazed joints defects in material, it further confirm that a leak
test technique is usually a quality control step to guarantee devise integrity and should
preferably be a onetime non – destructive test (NDT), without effect on the environment and
operators. VTECH recommended the halogen electronic detector soap solution, immersion
method, tracer gas leak testing and sniffing method to be used for leak detection.
UNEP (2010) explains leak detection to be the manual procedure carried out by a quality
technician for checking refrigeration system to identify possible leaks in tubes, joint or
connection. UNEP further identify use of soap solution as the most popular minimal cost and is
one of the most effective methods among serving technicians and that electronic refrigerant
detectors condition an element sensitive to a particular chemical component in a refrigerant.
Leak detected can be detected using nose by smelling, ear by listening, finger by touching oil and
eyes by visualization but the best method includes use of electronic method, bubble method.
Evacuations of Contaminants from Refrigerators and Air-conditioner Plant
Moisture is seen as contaminant in the Refrigeration and Air- conditioning system.
Ridwan (2010) affirmed that moisture as contaminant causes several operating problem in
Refrigeration and Air- conditioning system and that the most effective way to eliminate moisture
from a system is through the use a high vacuum pump to create vacuum deep enough to
evaporate ad remove this moisture. This view was supported by UNEP (2010) that also identified
gases that do not liquefy in the condenser are contaminants. It further recommended that all
unwanted vapours, gases, and fluid must be removed. The removal process is known as
evacuation. The process of evacuation usually involve attaching the system to a vacuum pump
and keep the pump running for some time while a deep vacuum is drawn on the system can best
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remove the contaminant. The evacuation equipment includes; Vacuum pump and Manifold
gauges. Vacuum gauge and the condition that will need the system to be Vacuum include:
Replacing circuit component, when the system has no refrigerant, if the refrigerant is
contaminated and after the lubricant is charged.
UNEP (2010) recommend that when the system is found to be free from leakage, allow it
to stand for a minimum of 24 hours under pressure. If no pressure drops occur the system is
ready for evacuation and the evacuation should be carried out by the specialist assigned by the
equipment manufacturers.
The Environmental Safe Refrigerant Service Tip and techniques (Certified Refrigerant
Services, 2013) endorse two stave vacuum pump is necessary to pull the deep vacuum below 500
microns, which are necessary for the proper evacuation and removal of water from the system.
It further emphasized that failing to reach required evacuation level before opening or
disposing appliances and knowingly releases refrigerants while repairing appliances and in order
to avoid moisture in the system, evacuation must be carried out before recharging. It is necessary
according to safe refrigerant service to confirm leak before evacuation. So you do not drag in air
moisture and other contaminants’ into the system, making subsequent evacuation much more
difficult.
Proper method of evacuation after initial installation of after service where the system has
been opened to atmosphere is critical to proper operation of an air conditioning or refrigeration
system, According to Refrigeration; Air conditioning Technology (2005) recommended that
when evacuating a system pull a vacuum until a 1000 microns is reached evacuation of the line
set and evaporator coil will take less than 15 minutes for a least residential unit; send stage allow
the system to continue the evacuation process until the vacuum level 500 microns or less. Then
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repeat the ‘standing test’ to determine if there is a decrease in level. If the leak rate has not
decrease then the system is still contaminated with moisture or the system has a small leak that
was not detected by the initial test. If the system has leak the gauge will continue to rise until
atmospheric pressure has been read and if the system still indicate moisture, a multiple
evacuation with a nitrogen sweep is recommended.
Trouble-shooting Electrical Panel in Refrigeration and Air-conditioning
Troubleshooting according to Andrew, Carl and Alfred (2000) as the process of analysis
of problems on the unit. Troubleshooting refrigeration and air-conditioning unit usually involves
fault finding in refrigerator, air conditioner which includes electrical components (Refrigeration
and Air condition Advanced Training Institutes, 2008).
Warren (2013) defined Electrical Panel to been a metal electrical service box that accepts
the main power to the home and distributes electrical current to the various circuits within the
home. He continued by saying that to expertly troubleshoot electrical panel, problems must be
solved by swapping only defective equipment or components in the least amount of time. One of
the most important features in doing this is the method used. An expert troubleshooter uses a
system or approach that allows them to rationally and methodically analyze a circuit and
determine exactly what is wrong. Warren further to identify five steps in troubleshooting
approach, these includes: Before you begin to troubleshoot any piece of equipment, you must be
conversant with your organization’s safety rules and procedures for working on electrical
equipment. These rules and procedures govern the approaches you can use to troubleshoot
electrical equipment (including your lockout/tag out procedures, testing measures etc.) and must
be used while troubleshooting; you need to gather information concerning the equipment and the
problem. Be sure you know how the equipment is designed to operate. It is much easier to
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analyze faulty operation when you understand how it should operate. Operation or equipment
manuals and drawings are great sources of information and are helpful to have available. If there
is equipment history records, you should review them to check if there are any recurring
problems. You should also have on-hand any documentation describing the problem. (i.e.,
trouble report, a work order, or even your notes taken from a discussion with a customer.), Most
faults provide obvious clues as to their cause. Through cautious observation and a little bit of
reasoning, most faults can be identified as to the actual element with very little testing. When
observing faulty equipment, look for visual signs of mechanical fault such as indications of
chafed wires, impact, loose components or parts lying in the bottom of the cabinet. Search for
signs of overheating, especially on relay coils, wiring, and printed circuit boards; don’t forget to
use your other senses when carrying out equipment inspection. The odor of burnt insulation is
something you won't miss. Listening to the sound of the equipment operating will likely give you
a clue to where the problem is located. Checking the temperature of components can also assist
in finding problem but be careful while doing this, some components may be alive or hot enough
to burn you, Pay attention to areas that were identified either by past history or by the person that
reported the fault. A note of caution here! Do not let these deceive you, past problems are just
that – past problems, they are not unavoidably the problem you are looking for now. Also, avoid
taking reported problems as fact; do the check yourself if possible. The person reporting the
problem may not describe it properly or likely made their own incorrect assumptions.
Warren recommended that when confronted with an equipment which is not functioning
properly you should; ensure you know how the equipment is designed to operate. It is much
easier to analyze faulty operation when you know how it should operate; Note the state of the
equipment. You should check the state of the relays (energized or not), which lamps are lit,
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which auxiliary equipment is energized or running. This is the best time for the equipment to be
given a thorough inspection (using all your senses). Check for signs of overheating, mechanical
damage, unusual smells, sounds etc.; Test the operation of the equipment together with all of its
features. Take record of any feature that is not operating properly. Make sure you observe these
operations carefully. This can give valuable information regarding all parts of the equipment. At
this stage, you apply logic and reasoning to your observations to determine the problem area of
the malfunctioning equipment. Most times, when equipment malfunctions, some parts of the
equipment will work properly while others not.
The key is to use your observations to rule out parts of the equipment or circuitry that are
operating properly and not contributing to the cause of the malfunction. You should continue to
do this until you are left with the part(s) that if faulty; probably the cause of the symptoms that
the equipment is experiencing. To help you define the problem area, a schematic diagram of the
circuit should be made available in addition to your noted observations. Starting with the entire
circuit as the problem area, take note of observations and ask yourself what does this indicate
about the circuit operation? If an observation shows that a section of the circuit appears to be
operating appropriately, you can then remove it from the problem area. As you eliminate each
part of the circuit from the problem area, make sure to find them on your schematic. This will
assist in keeping track of all your information.
Once the problem area(s) have been defined, it is important to identify all the possible
causes of the malfunction. This typically involves every part in the problem area(s). It is
important to list (actually write down) every fault which could cause the problem no matter how
isolated the possibility of it occurring. Use your initial observations to help you do this. During
the next step you will remove those which are not likely to happen. Once the list of possible
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causes has been made, it is then necessary to highlight each item as to the probability of it being
the cause of the malfunction. The following are some rules of thumb when highlighting possible
causes. Although it could be possible for two components to fail simultaneously, it is not very
likely. Start by checking for one faulty component as the culprit. First, look for components
which have a tendency to wear out or already burn out, such as mechanical fuses, switches, relay
contacts, or light bulbs (Remember, fuses burn out for a reason. You replace them only after
finding out why before they burn out.); the next most possible cause of failure are motors, coils,
transformers and other devices with windings. These normally generate heat and, with time, can
malfunction; All connections should be your third choice, especially bolted type or screw type.
Over time these can cause a high resistance when loosen thereby causing overheating and
eventually will burn out. Connections on equipment subjected to vibration are especially prone to
coming loose and finally, look for defective wiring. Pay attention to areas where the wire
insulation could be damaged causing short circuits. Don't rule out incorrect wiring, especially on
a new piece of equipment.
Testing an electrical equipment can be hazardous. The electrical energy contained in
many circuits is enough to injure or kill. Ensure you follow all your companies’ safety
precautions, rules and procedures while troubleshooting. Once you have identified the most
probable cause, you must either prove it to be the problem or rule it out. This can sometimes be
done by careful examination however, in many cases the fault will be such that you cannot
identify the faulty component by observation and analysis alone. In these circumstances, test
instruments can be used to help narrow the problem area and identify the problem component.
There are many types of test instruments used for troubleshooting. Some are specialized
instruments designed to measure various behaviors of specific equipment, while others like the
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multimeters are more general in nature and can be used on most electrical equipment. A typical
multimeter can measure AC and DC Voltages, Resistance, and Current. A very important rule
when taking meter readings is to predict what the meter will read before taking the reading. Use
the circuit schematic to determine what the meter will read if the circuit is operating normally. If
the reading is anything other than your predicted value, you know that this part of the circuit is
being affected by the fault.
Depending on the circuit and type of fault, the problem area as defined by your
observations, can include a large area of the circuit creating a very large list of possible and
probable causes. Under such circumstances, use a divide and eliminate testing approach to
eliminate parts of the circuit from the problem area. The results of each test provide information
to help you reduce the size of the problem area until the defective part is identified. Once the
fault is determined, the faulty operation on the circuit can be fixed by replacing the defective
component. Make sure that the circuit is locked out and you follow all safety procedures before
disconnecting the part or wires. After replacing the part, you must test operate all features of the
circuit to be sure you have replaced the proper component and that there are no other faults in the
circuit. Specifically troubleshooting air -conditioning electrical components according to
Warren (2013) quoted earlier, described procedure taken when trouble shooting electrical panel
on Air-condition to take the following procedures:
When the unit refuses to start, check the breaker, check the disconnection and fuses, and
check to make sure you have right power supplied to the unit. If the breaker is tripped off /or fuse
is blown, check the unit for earthing. Disconnect the cable from the air- conditioning compressor
terminals and check for grounded, shorted, or open windings. Confirm the condenser and
evaporator fan motors for grounded or shorted windings. Check the control and power circuits
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for shorts or grounds. Check for power at the evaporator fan relay. If it gets power but the fan
does no start, it has failed. If it gets power and the contacts close, but the fan does not run. Check
for voltage on the load side of the relay, check the cable to the fan, check the fan windings and
the capacitor, and check to see if something is stuck in the blower and stopping it from turning.
Verify the cooling control signal from the thermostat. Check pressure if the refrigerant is
low, the safety device for low pressure will open and the unit will not run .Check the safeties. If
the oil safety switch has cut-off, confirm the oil level. It will also trip if the contactor closes but
the compressor does not run for other reason, then check for open compressor windings, confirm
that the compressor terminal connections and contactor connections are firmly fix, and confirm
that there is good voltage at the compressor when the contactor pulls in. If the high pressure
control is open, check the pressures. If head pressure has dropped below the cut in point of the
safety, and when it is an automatic reset type, the safety has failed. If the safety is a manual reset
type, push the button and see if it will reset.
Check the voltage monitor if there is one, If your voltage is within range of the setting,
the safety control contacts should be closed, When it is not, the monitor has failed, If there is a
delay timer fails, check across the control terminals, If the delay timer contacts never close, it has
failed, If the safety contacts control are closed, then control power at the contactor, If there is no
control power at the contactor coil, look for broken wires, If you have control power at the
contactor coil but the contactor doesn't pull in, then the contactor is bad, If you are on an
troubleshooting air conditioning on contactor pulls in but the compressor does not start, check
for open compressor windings, verify that the compressor terminal connections and contactor
connections are tight, and verify that there is actually good voltage at the compressor when the
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contactor refuse to energize and it is a single phase compressor, confirm the start relay and the
capacitors.
The best way to test the start capacitors and relay is to replace them with new parts, if
the condenser fan doesn't run, check the relay, motor windings, fan blade, and capacitor the same
way as with the evaporator fan. Be thorough as you trace down wiring and look for failed
components, and always follow safety precautions during your air conditioning troubleshooting
jobs. Warren further recommended steps in Air conditioning troubleshooting on a unit that runs
but doesn't seem to be cooling efficiently to include, Check the evaporator and condenser fans,
Verify the motors to be the correct horsepower, confirm that the motor rotates in the proper
direction and at the correct rpm, Verify that the fan and blower blades are clean, that they're the
correct size and pitch, and that they are turning in the right direction, Verify that the evaporator
and condenser coils are clean and air flow is not blocked. Verify that the air filter is clean,
Verify that the condenser is getting normal temperature outside air, and that another unit isn't
blowing hot air into it, Verify that the evaporator supply and return ducting is not leaking; losing
cold air or picking up warm outside air.
Air- conditioning troubleshooting takes the following steps: attach your gauges and
check your pressures and temperatures, with the unit off, and pressures equalized, verify that the
system contains the correct refrigerant. You can do this by taking the temperature of the
evaporator coil. The temperature obtained should match the pressure/temperature indication on
your low side gauge or pressure/temperature chart. Run the unit and check operating pressures.
When the space has cooled down and is about 5 degrees above design temperature, look for the
following pressures and temperatures. Suction pressure should be in the range of 35 to 40
degrees below return air. Discharge pressure should be in the range of 20 to 35 degrees above
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ambient air. Superheat should be 20 to 30 degrees at the compressor. Sub cooling should be 10 to
15 degrees at the outlet of the receiver or condenser. Air temperature rise through the condenser
should be 20 to 30 degrees. Air temperature drop through the evaporator should be 15 to 20
degrees. If all of your operating characteristics fall within these ranges, the unit is running well.
At this stage of air conditioning troubleshooting, if there is still a concern about the unit not
cooling properly, you will need to do a capacity check.
NADCA (2006) indicated that a clamp meter is a great tool for troubleshooting electrical
motor faults, especially meters designed to accurately measure both AC voltage and AC current.
These meters allow current to be determine without breaking into the electrical circuit. A
compressor failure is often caused by an electrical fault. In order to check the compressor for
electrical problems, remove the electrical terminal cover and check the following external
connections. Check line voltage at the load center with the compressor off. Low line voltage
causes the motor to consume more current than normal and may result in overheating and
premature failure. Line voltage that is too high will cause excessive current surge at motor start,
again leading to premature failure, check line voltage at the motor terminals with the compressor
on. The voltage should be run 10 percent of the motor rating, check running current. The
readings should not exceed manufacturer's predetermined load rated amps during heavy load
periods. Low amps are normal during poor load conditions. Excessive high current, a bad
capacitor, a faulty start relay, or an indication of excessive bearing fatigue. When performing
electrical measurements on compressors with internal thermal motor protection devices that have
been running extremely hot, be sure to allow the compressor time to cool down prior to the
electrical test. This will allow the device to reset to its normal position.
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Recovery / Recycling of Refrigerant
Certified Refrigerant Services, (2013) affirms that the major element in the utilization of
fluorocarbon refrigerants is the recovery, recycling and reclamation of used refrigerants so that
they can be recycled for further commercial use or destroyed. Hydro fluorocarbons can be
recycled, recovered and reclaimed from many applications, including mobile air conditioning,
stationary air conditioning and refrigeration.
There are many economic and environmental benefits derived from recovery, recycling
and reclamation efforts worldwide. The major benefits include: To expand market opportunity
for refrigerant; Reduced environmental compliance costs; Minimized atmospheric emissions and
reduced environmental impact; Reduced need for fresh refrigerant; and improve lifetime of
refrigeration equipment due to contaminant removal.
The association described Refrigerant Recovery involves the removal of a refrigerant
from a system and the placement of the refrigerant into a container. The recovery process
includes: Is conducted whenever technicians need to open or destroy of air conditioning or
refrigeration equipment, removal of refrigerant vapor (heels) to established evacuation levels to
maximize the amount of refrigerant recovered and minimize releases. Involves service
technicians, appliance disposal facilities, equipment operators, equipment and refrigerant
manufacturers.
Refrigerant Recycling involves processing used refrigerants to reduce contaminants, than
reusing the refrigerant in the same system or returning to the system. Recycling is allowed only
when recharging to the same owner’s equipment.
UNEP (1999) defined recovery to as the removal of refrigerant in any condition.
Recovery became necessary due to the effect of ozone depletion on the earth. Research has
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proved that the leading cause of ozone depletion is chlorofluoro-carbons (commonly called
hydrofluorocarbon’s) a family of manmade chemicals which are commonly used in most Air
conditioners and Refrigerators, according to Maskell and Johnson (2001), there is now a large
concentration of chlorofluoro-carbons and other ozone destroying chemicals in the atmosphere,
and some of them have life span of 25 to 400 year, and that almost all of the chlorofluoro-
carbons ever emitted are still in the atmosphere and will continue to destroy ozone for many
years.
Keatinge (2000) reported that ozone depletion was first hypothesized in 1974 by Doctor
Mario Molina and Sherwood Rowland F. two American Scientist who were concerned about the
impact of chlorofluoro-carbons on the ozone layer, their hypothesis about ozone depletion was
first met with a great deal of skepticism, but over time, however, scientific discovery has not
proved their hypothesis wrong, this prompted almost every country in the world to action. In
1995, their contribution to solving a global environmental pollution that could have catastrophic
consequences was acknowledged with the award of the Nobel Prize in chemistry to Rowland
Molina. Keatinge went further to report that the first real evidence of ozone depletion was
confirmed in 1985 by the British Antarctica Survey team, which had been measuring the ozone
layer over the south Pole for 18 years and found a dramatic thinning in the ozone layer which
develop every year from September to November, since then, ozone concentration in this area
have grown steadily thinner, with depletions of up to 60 percent occurring in recent years.
Ozone depletion has resulted to global warming. Global warming according to Hormer
(2007) has resulted to what is also known as Greenhouse effect. According to Hormer, the Green
house Earth” is surrounded by a shield of atmospheric gases, rather than glass or a plastic cover.
The air that makes up out atmosphere consists primarily of Nitrogen and Oxygen molecules.
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Nitrogen 78% and Oxygen at 21%. A large number of trace glass make up the remainder of air
composition. Many of these including carbon dioxide, chlorofluoro-carbons, and methane are the
so called “greenhouse” gases. Hormer continued to explain how the Greenhouse gases cause
global warming. According to his explanation, the sun, powered by ultra-voilet, nuclear fusion
reaction produces radiant energy in the visible and ultraviolet region with relatively short
wavelengths, the sunlight that strikes the earth, about 70% is absorbed by the planet and the
atmosphere, while the other 30% is immediately reflected, and if the earth did not re-radiate most
of this newly absorbed energy back into atmosphere, the world would continue to get hotter.
Further scientific observation according to Esptein & Manwelt (2001) has shown that the
concentration of ozone in the stratospheric is decreasing. This depletion of the ozone layer is
thought to be caused by the emission of volatile chemical containing chlorine and bromine,
particularly those which do not break down in the lower atmosphere. He noted that to prevent
further damage, the Montreal Protocol was signed by the nations of the world. As such, the
production of chlorofluorocarbon and Hydrofluorocarbon is being phased out and very shortly,
the only source of chlorofluorocarbons will be reclaimed refrigerants. This process of recovering
for reclaiming is known as management of ozone depleting refrigerant.
Among the management plan for ozone depleting refrigerant, research carried out in
Harvard University recommended that , leak detector should be installed where it is appropriate
and retrofitting plan for existing equipment in the future. Since the handling of many new
refrigerants and oil differs significantly from traditional techniques, the Harvard University
(2010) further recommended that staff, who works on the Refrigerating plants should be trained
with the new materials. This will reduce inefficiencies and plant failures that could have arisen
from incorrect procedures, followed particularly where refrigerant replacement known as
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retrofitting is being carried out. The Harvard went further to recommend that facilities with Air-
conditioning and Refrigerating equipment are required under Environmental Protection Agency
(EPA) regulations to plan for refrigerant recovering to capture any of the harmful refrigerant gas
that might be emmitted into the air. This arrangement is necessary because refrigerant gases
contain hydrochlorofluorocarbons (HCFCS), which causes severe damage to the ozone layer and
promotes global warming. Basically refrigerant recovery is to recycle, reclaim or properly
destroy hydro chlorofluorocarbons. These efforts will reduce harmful greenhouse gas (GHG) and
ozone depleting emissions from reaching the atmosphere, eliminate the need for new refrigerants
and provide a market for used refrigerant after they are cleaned and recycled.
The Harvard University further describes the need and process of recovering to involve
removing the refrigerant gas from Air-conditioning equipment or refrigeration system such as
grocery store cooling racks and placing it safely into a pressurized container. This process takes
place when equipment is being discarded for a service event or when refrigerant gas needs to be
adjusted due to a seasonal adjustment. The recovering process maximized any release of the
harmful gas into the atmosphere and that refrigerant recovering can be done during a retrofit and
then recycled to service other equipment. When the refrigerant is safely removed from the
system, it is brought to an approved facility and tested for purity. It is then shipped to recycling
facilities. The report by Harvard University further recommended refrigerant recovery at large
commercial or industrial facilities may require specialized equipment and techniques to enable a
high volume of recovering.
The Clean Air Act of 1994 Section 608 as quoted by Harvard University (2010)
stipulated that Evacuation requirement on Service Practice Requirement indicated that
technicians are required to evacuate Air-conditioning and Refrigeration equipment to established
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vacuum levels when opening the equipment for service, maintenance and repair or disposal.
UNEP (1999) observed that poor servicing procedures and lack of refrigerant recovery and
recycling often lead to the emission of a significant proportion of the refrigerants directly into the
atmosphere. As a measure of Refrigerant Management Plan (RMP), the consumption of
chlorofluoro carbons are no longer used in developed countries by the beginning of 1996, except
the 10,000 tons required for vital uses. Developing countries are given a grace period and from
July 1999, their first control measure – the freeze on the production and consumption of
chlorofluoro carbon from 1995-1997 levels has been effective. Total phase-of chlorofluoro-
carbon in developing countries is in the refrigeration sector in developing countries is best
achieved through an integrated nationwide strategy that addresses the key technical and policy
issues – a Refrigerant Management Plan. Such a plan includes priorities–activities such as public
awareness, campaigns, training and certification of service technicians, conversion projects,
establishment of refrigerant recovering and recycling system and suitable policy and regulatory
support frameworks, monitoring of chlorofluorocarbon consumption and improvement of data
collection systems control.
Among the steps that were laid out for proper Refrigerant Management programme was
to identify and approach service workshops and wholesalers when all the workshops have been
identified, they should be informed of the planned Recovering and recycling systems; that is
their full commitment to participation is important. Secondly, training and supervision of
individuals work on refrigerating and air-conditioning equipment should be scheduled and when
they are many, train-the-trainer workshop should be considered. This training should be
coordinated or combined other training programmes. The training courses should provide
training and practical hand-on session on the following subjects: Phase-out schedules for ozone
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depleting substances under the Montreal protocol; The National Refrigerant Management Plan;
The effect of ozone layer destruction; Main principles of Refrigerant and Air-conditioning; Good
servicing practices, including recovering, recycling; Use of Recovering and Recycling devices;
Preventive maintenance programmes and record keeping; Retrofitting to alternative refrigerants
and General trade safety; Refrigeration association and certification scheme.
UNEP (2006) recommended that the local refrigeration service companies planned to
participate in the Recovery and Recycling system and received Recovery and Recycling
equipment should be closely involved in project preparation. The service technicians should
receive training on the explicit features of specialize tools that are involved. UNEP continued by
saying that Recovering and Recycling systems will function more effectively if the managers of
refrigeration and air-conditioning units and technicians of refrigeration service company are fully
equipped and trained and that in order to adopt quality procedures for recycled refrigerant, the
following procedures must be adopted: Using only certified Recovering and Recycling
equipment; Employing only skilled personnel and provide appropriate training; Testing acidity
with paper strips; Performing preventive and visual inspections of the oil or the lubricant through
the sight glasses; Applying good practices and proper procedures; Avoid mixing refrigerants;
Using refrigerant identifiers to recognize the type of the refrigerant or refrigerant mixtures;
Never using refrigerants after a compressor burns-out and using evaporation processes during
recycling.
James (2008) noted that prior to the action of the EPA regulations, it is a common
practice to vent refrigerants from systems to the atmosphere during service or replacement, but
today, technicians must use certified recovery and recycling equipment to remove refrigerant
charge from a system, rather than venting it. James further said that any technician working with
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refrigerants must have undergone proper training and certification, but basic training is not
enough. James also stressed that the management training of ozone depleting refrigerants must
focus on safety since hydrochlorofluorocarbons and chlorofluorocarbons are heavier than air, in
which in a confined space, a sudden and sufficient refrigerant discharge can result in the
displacement of air and asphyxiation which causes starvation that leads to death in accidents
involving refrigerant.
Bouma (2011) under the International Energy (IEA) Heat Pump centre in a report of a
study carried out on refrigerant recovery, recycling, reclamation, and disposal procedures and
practices pursued in major markets located in Europe, Asia and North America confirmed that in
the Netherlands, the industry decided to launch compliance on regulations for the prevention of
refrigerant release by including certification for companies working on such Refrigeration and
Air-conditioning installation establishment of technical requirements necessary to lessen leakage,
and training and education of field engineering staff.
The Environmental Protection Agency (2008) reported that the stratospheric ozone layer
safeguards the earth from penetration of destructive ultraviolet (UV-B) radiation based on the
basis of substantial scientific evidence, that the ozone is depleted, the national and international
consensus exist that some artificial halocarbons, including chlorofluorocarbons (CFCs)
halocarbon, tetrachloride, and methyl chloroform must be controlled because of the risk of
depletion of the stratospheric ozone layer through the discharge of chlorine and bromine. The
depletion causes penetration of UV-B radiation increase resulting in potential health and
environmental impairment including increased rate of certain skin cancers and cataracts,
suppression of the immune system, damage to plants including crops and aquatic organism,
increased formation of group-level ozone and increased weathering of out-door plastics.
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Retrofitting Alternative Refrigerants
Retrofitting according to ASHRAE (2010) earlier quoted defines retrofitting as the
replacement of corresponding alternative. Refrigerant with an existing ozone friendly
refrigerant which involves changing parts that are compactable with new refrigerants. United
Nation Environmental Protection (UNEP) (2006) defines retrofitting as the procedure of
replacing ozone depleting substances (ODS), hydro fluorocarbon (HFC) refrigerants in existing
plants with zero ozone depleting potential (ODP) or zero global warming potential (GWP)
refrigerants. Retrofitting usually requires modifications such as a change of lubricant,
replacement of compressor or expansion device. If conversion does not require such major
modifications, the alternate refrigerant is called a chop-in replacement or retro-fill process.
Retrofitting from ozone depleting substance system to an ozone friendly system usually
requires a thorough investigation of the system and such investigation includes trouble
shooting the electrical panel or parts of the system.
National Refrigerants, (2013), recommended that while retrofitting, the following guidelines
should be followed; R-22 and mineral oil interact with many elastomers causing swelling,
which helps to complete the intended seal. There is also a measurable rise in hardness over time.
One concern of this process, however, during a retrofit away from R-22, the new refrigerant/oil
combination may lead the seal to shrink and allow leakage. Any process that disturbs the seating
of the gasket, such as operating ball valves or depressing Schrader valves, may also cause leaks
to occur. Therefore, for any retrofit job it is recommended to replace o-rings on caps, Schrader
valve cores, elastomeric seals, and any seals found to be leaking before the retrofit takes place,
some refrigerants will have very similar run-time capacity and pressure drop across a
Thermostatic Expansion Valve while others may be different enough from R-22 that the valve
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will become undersized. Thermostatic Expansion Valve capacity is determined by: (1) three
system conditions: evaporator refrigerant saturation temperature, liquid refrigerant temperature
entering the Thermostatic Expansion Valve and the pressure drop across the Thermostatic
Expansion Valve port, and (2) thermodynamic properties of the refrigerant. It cannot be
assumed that the Thermostatic Expansion Valve capacity will remain the same after converting
R-22 system to alternative refrigerant because in some cases the Thermostatic Expansion Valve
capacity will be reduced when used with the alternative refrigerant. Since each refrigerant has
its own pressure/temperature characteristics, some R-22 alternative refrigerants might require
the use of a Thermostatic Expansion Valve with R-404A thermostatic element. Regardless of
whether the Thermostatic Expansion Valve is replaced, for maximum evaporator efficiency, the
superheat should be inspected and regulated to the equipment manufacturer’s specification;
smaller systems with capillary tubes may not perform the same during retrofitted. Until the
length of the tube is adjusted to match the performance of the blend, the only other way to alter
the operation of a cap tube system is to alter the refrigerant charge size, Filter driers and/or
cores should be swapped during the retrofit process. The filter drier should be changed with the
same type currently in use in the system; most retrofit blends have some degree of temperature
glide. System operation gets affected (superheat adjustment, other controls) and fractionation
needs to be considered for systems that may discharge while not running for long periods, Some
refrigerant blends can run at different pressures than R-22 to achieve the same temperatures.
Any pressure-related control should be adjusted to compensate for the different pressure; In
general, HFC blends will require the use of polyester lubricant. Traditional retrofit procedures
requires the mineral oil level to be below 5%. This is typically realised by draining oil from
compressors and the oil management system and replacement with POE up to 3 times. Follow
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compressor manufacturer guidelines for recommended levels and techniques, It is highly
recommended that after the system must have been retrofitted to the fresh refrigerant, that
required time is taken during the start-up process to tune the system correctly. While some
substitute refrigerants might be essentially less efficient than R-22, the actual efficiency of the
former R-22 system can increase after the retrofit if the following steps are taken: conduct a
thorough leak check and repair all leaks, replace existing filter driers and suction filters,
properly charge the system, optimize the compressor staging, set all pressure regulating valves
to design specifications and most important- set all Thermostatic Expansion Valves to the
correct superheat.
National Refrigerants, (2013), further recommended the general retrofitting procedure for
larger refrigeration systems as follows; Collect baseline data for operation of the system with
existing R-22 charge. Take note of any cases or system components that do not appear to be
running properly and not any required repairs, Check the system for leaks while still charged
with R-22 to identify and repairs needed during the retrofit process, Disconnect electrical
connection to system and properly recover the R-22 charge. Record the amount of R-22
recovered and perform any necessary maintenance or repair operations previously identified,
they including: replacement of seals and gaskets, filter drier replacement, leak repairs,
compressor oil change and replace Thermostatic Expansion Valves element and refrigerant
distributor nozzle as required.
If preferred, pressurize and leak check the system by ideal method. Evacuate the system
down to 250 microns and check that it holds. Charge the system with the retrofit blend to around
90% to 95% of the recovered R-22 charge size. Ensure the refrigerant is evacuated from the
cylinder as a liquid. Restart the system and allow it to stabilize. Compare the current operation
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data to that of R-22 run time data. Adjust procedure as needed. Check superheat on the
Thermostatic Expansion Valve and adjust as necessary. Label the system with identification
stickers displaying the new refrigerant and oil charge.
It is also recommended that retrofitting for smaller Refrigerator and Air-conditioners
should be as follows: Collect baseline data for the operation of the system with existing R-22
charge. Take record of any noticeable performance problems with the system. Leak check the
system while still charged with R-22 to identify any repairs required during the retrofit process.
Disconnect electrical power to system and carefully recover the R-22 charge. Record the amount
of R-22 recovered. Perform any required repair or maintenance operations previously identified,
including: replacement of Schrader cores, drier replacement, filter change oil or add small
amount of POE if required (follow equipment manufacturer’s guidelines).
When retrofitting an air conditioning system, material compatibility and the condition of
the existing seals and gaskets must be taken into account. The retrofitting checklist also needs to
be considered which have to do with the following: Record baseline data on original system
performance, Recover refrigerant charge using appropriate recovery equipment, choose
compressor lubricant, Record the amount of refrigerant recovered. Consult the compressor
manufacturer’s data to confirm that the synthetic grade and weight is right for use with R-407C /
R-422D, R-422D: Use of POE (polyol ester lubricant) will enhance oil return if required, R-
407C requires minimum of 15% POE oil, if required, remove the existing lubricant from the
compressor’s separators and oil reservoirs, Measure amount (volume) of lubricant removed,
Recharge the system with polyol ester lubricant, Change lubricant filters if present, use the same
amount (volume) that was removed, Evaluate the expansion devices: consult the valve
manufacturers for necessary recommendations. No alterations are necessary in most cases,
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Evaluate and replace all elastomer seals including Replace filter driers Schrader valves, and
suction filters, evacuate the system, Leak check the system, and Charge the system with the new
refrigerant. In the case of R-407C / R-422D discharge only liquid from the charging cylinder,
Initial charge should be approximately 85% of the R-22 charge by weight record the amount of
refrigerant charged, Adjust refrigerant charge if necessary in increments of 5 percent of original
charge weight and Label components and the system with the type of refrigerant and lubricant.
Honywell Genetron (2012) suggested that while retrofitting an existing air conditioning
system, material compatibility and the state of the existing gaskets and seals must be considered.
It is recommended to replace any O-rings, seals and other elastomers used in the system, (as
expected in any retrofit to HFC). In most air conditioning and heat pump systems this applies to
the cap seal material and Schrader valve seal.
Record baseline date
Before making any hardware replacement, compare current system operating data with
normal operating data. Fix any deficiencies and take record of the final data as a performance
baseline. Data should include pressure measurements and temperature throughout the system
including the compressor suction and discharge, evaporator, condenser and expansion device.
These measurements will be use when carrying out adjustment the system with an alternative
Genetron refrigerant.
Isolate R-22 refrigerant charge
The HCFC refrigerant charge should be removed from the system using an approval
recovery machine capable of meeting or exceeding the required levels of evacuation. The charge
must be collected in a recovery cylinder.
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Do not vent the refrigerant
Knowing the recommended R-22 refrigerant charge size for the system is helpful. If it is
not known, weigh the entire amount of refrigerant removed. This quantity can be used as a guide
for the initial quantity of alternative Genetron Refrigerant to be charged to the system.
Choose compressor lubricant
In most instances, the lubricant in use with R-22 is a mineral oil or alkyl benzene. Polyol
ester lubricants are recommended for use with Genetron 407C by the equipment manufacturers.
Genetron 422D retrofitting of a system with short connecting lines will not require an oil change
or alteration. Honeywell recommends the use of a miscible lubricant approved by the compressor
manufacturer. In this case, POE oil is recommended for R-422D. Difference among lubricants
makes it difficult to assume that they are interchangeable. Check with the compressor
manufacturer for the correct system being retrofitted. If the lubricant is contaminated, changing
the lubricant is warranted.
Field trials have indicated that adequate oil return can occur in HFC retrofit systems
when 15% -20% of the lubricant operating charge is synthetic oil. Systems with receivers or low-
side accumulators (heat pumps) will require a higher ratio of POE to mineral oil.
Evaluate the expansion device
Honeywell recommends the equipment manufacturer is consulted before retrofitting.
Most HCFC-22 A/C systems with either expansion valves or capillary tubes operates
satisfactorily with Genetron 407C or 422D.
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Replace the filter drier
Following system maintenance, recommended service practice is to replace the filter
drier. The two types of filter driers commonly used in refrigeration equipment includes: loose-fill
and solid-core.
Check with your wholesaler to make sure the replacement filter drier is compatible with
the Genetron refrigerant being used. When changing to an HFC-miscible lubricant, particularly
to a more polar lubricant such as polyol ester, it may be beneficial to add a suction line filter.
Reconnect the system and evacuate
Use normal service practices in reconnecting and evacuating the system. To remove air
and other non-condensable, Honeywell recommends evacuating the system to a full vacuum of
1,000 microns or less form both side of the system. However, attempting to evacuate a system
with the pump connected only to the low-side of the system will not adequate remove moisture
and non-condensable such as air. Use suitable electronic gauge to measure the vacuum. An
accurate reading cannot be read using a refrigeration gauge.
Check the system for leaks
Check the system for leads using normal service practices.
Charge system with HFC refrigerant
When replacing HCFc-22 with Genetron 407C or 422D, use the same charging
techniques that you would use for the refrigerant being changed. When working with
Genetron407C or 422D always remember that these are blend refrigerants. It is necessary that
blend refrigerants be charged by removing only liquid from the cylinder.
A throttling valve should be used to control the flow of refrigerant to the suction side to
confirm that the liquid is converted to vapor prior to entering the system.
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Note: to prevent compressor damage, do not charge liquid into the suction line of the unit.
Systems being charged with Genetron 407C or 422D needs slightly smaller charge size than
HCFC-22. For optimized capillary tube systems or expansion valves, the typical charge size
relative to the HCFC-22 being replaced appears below. As part of general practice, Honeywell
recommends that the system should be charged initially with 85 percent by weight of the original
system charged and then adding refrigerant necessary in 5% increments to obtain equal baseline
performance.
Check system operation
Start the system and allow conditions to stabilize. Should the system be undercharged.
Add more refrigerant in increments of 5 percent by weight of the original charge. Continue until
desire operation conditions are achieved. It may be required to reset the pressure cutouts to
compensate for the change in pressures of the replacement refrigerant. This process should be
done carefully to avoid exceeding the approved operating limits of the compressor and other
system components. The use of an enhanced capillary tube makes the system more sensitive to
charge and /or operating conditions. Accordingly, system performance will change swiftly
whenever the system is overcharged (or undercharged). To prevent overcharging, it is best to
charge the system by first taking reading of the operating conditions (including discharge and
suction pressures, compressor amps, suction line temperature, superheat) rather than using the
liquid line sight glass as a guide.
For blend refrigerants, pressure-temperature data will include bubble pressure and dew
pressure data will include bubble pressure and dew pressure data. To decide superheat, use the
dew pressure column. To decide sub cooling, use the bubble pressure column. To find average
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evaporating or condensing temperature, find the pressure in both the bubble and dew columns
and take the average of the two corresponding temperatures.
Label components and system
After retrofitting the system with Genetron 407C or 422D, label the system components
to recognize the specific refrigerant and indicate the type of lubricant (by brand name) in the
system. This will help to ensure that, the proper refrigerant and lubricant will be used to service
the equipment in the future. Summarized the procedure for retrofitting as follows:
Recommended retrofit checklist
Record bade line data on original system performance; Recover refrigerant charge using
appropriate recovery equipment, Record the amount of refrigerant recovered, Choose compressor
lubricant. Consult the compressor manufacturer’s data to verify that the same synthetic grade and
weight suitable for use with R-407C/R-422D, R-422D: Use of POE will enhance oil return if
required, R-407C requires minimum of 15% POE oil, if required, drain the existing lubricant
from the compressor’s separators and oil reservoirs; Measure amount (volume) of lubricant
removed; Change lubricant filters if present, Recharge the system with polyester lubricant, use
the same amount (volume) that was removed, Evaluate the expansion devices: consult the valve
manufacturer for recommendations. No change is necessary in most case, Evaluate and replaces
all elastomeric seals including Schrader valves, Replace filter driers and suction filters, Leak
checks the system, and evacuate the system. Charge the system with the fresh refrigerant. In the
Cade of R-407C/R-422D remove only liquid from the charging cylinder, Initial charge should be
approximately 85% of the R-22 charge by weight record the quantity of refrigerant charged. And
adjust refrigerant charge if necessary in increments of 5 percent of original charge weight.
Label components and the system with the type of refrigerant and lubricant.
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Commissioning of Refrigeration and Air-conditioning plants
Commissioning is usually carried out for newly completed installations and existing ones
after major alteration. Commissioning according to Architectural Service department (2007) the
main aim of commissioning refrigeration and air conditioning equipment is to verity proper
functioning of the equipment/ system after installation, to verify that the performance of the
installed equipment/ systems meet with the specified design intent through a series of tests and
adjustment and to capture and record performance data of the entire installations as the baseline
for future operation and maintenance. It further emphasized that the purpose of these test is to
ensure that all components and system are in a safe and satisfactory condition before start up.
Acquiring mastering skills in these specific areas in repair and installation of refrigeration and air
condition require that technologist who do not acquire the needed skills need to be retrained.
Paul (2005) said that a comprehensive commissioning program identifies and corrects
costly performance deficiencies. It’s not a stretch to imagine the lifetimes cost of 10 percent duct
leakage versus 5 percent or less, which will lead to additional operating expenses. Similarly, it is
not difficult to envision an HVAC system failing to perform to specification.
Paul further said that in a study of the effect of commissioning on the performance of two
buildings of different dimensions, the Oregon Department of Energy discovered direct energy
savings of 5 to 10 percent. In a 22,000 – square-foot office building, annual energy savings of
$7,600 ($0.35 per square foot) were achieved. While in a 110,000-square-foot building, annual
energy savings of $12,276 ($0.12 per square foot) was realized following commissioning.
Likewise, a Lawrence Berkeley National Laboratory study on commissioning discovered that
commissioning is also one of the most cost-effective means of improving energy efficiency in
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commercial buildings. Actually, the authors resolved that commissioning potentially can save as
much as $18 billion a year in commercial buildings.
Additionally, the Berkeley study projected a median savings of $1.24 per square foot (in
a range of $0.23 to $6.95) in non-energy impacts, this means items identified in the
commissioning process has no effect on energy consumption-such as reduced change orders and
increased equipment life. Additionally these benefits the intangible savings associated with
avoiding complaints, system displaced tenants and downtime. Added together, the savings
associated with non-energy impacts and intangibles far offset direct energy savings. Actually, in
new construction, the savings from non-energy impacts will ordinarily pay for the
commissioning fee, or more.
Besides, the shortages found and corrected during the commissioning process makes the
facility to become significant more functional upon delivery to the owner. A good example of a
non-energy impact comes from a recent project, where a commissioning team found a violation
of the plumbing segment of the project specification. Unrelated metals were wrongly used and
would have resulted in speeded corrosion of the chilled water piping. Fixing this problem will
save the owner more than the payment for commissioning.
Correcting design errors
Commissioning has the ultimate impact when the commissioning consultant is involved
during at the design phase of project. The design-phase observations and planning along with
construction-phase corrections prevents delayed facility opening and business stoppage. These
corrections also creates front-end savings. This is the importance of hiring a commissioning
engineer at the design development phase instead of waiting until the late stages of construction.
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A commissioning agent partaking in the project soon enough to make meaningful contributions
to the design as well as the project construction.
Commissioning engineers are involve in the design process by: Developing a draft
commissioning plan outlining the project responsibilities and roles, developing commissioning
specifications for the construction reviewing designs and documents, maintainability, operations
and bid documents. During the design stage, the commissioning engineer will comment on the
ability of the systems, as been designed, to be tested and offer concrete suggestions to make the
systems more testable. The agent will simplify the basis of design with respect to the
performance goals that need to be confirmed and may suggest minor design modifications to
mechanical rooms to improve layout, maintainability and serviceability. By gaining a thorough
understanding of the design, the consultant will be able to develop relevant and accurate test
scripts to be performed in the construction phase. This will decrease the amount of time
necessary for commissioning, focus the commissioning effort on critical systems and decrease
the total amount of time spent commissioning the facility.
Training Facilities in Capacity Building in Refrigeration and Air-Conditioning
An important characteristic of modules is the method in which knowledge is structured.
As in programmed training, the learning hierarchies are presented in small steps. Compare to
formal size as they must be in the “frames” of a formal programme. In modules students can, at
least to a degree, decide the size of each learning step simply by changing the degree of
interaction with the material, or by neglecting familiar work while focusing on less familiar
areas.
It is well established that students differ in their responsiveness to different media of
instruction. Some learn best through reading; others learn more from still pictures and films; and
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still others must hear in order to learn. Some students need to touch the objects to be studied. All
students learn from one another and from dialogue with friends, colleagues and teachers. In
modules utilizing a variety of media can cater for all these aspects. Students can study the
material in a variety of ways and individuals can find learning sequences involving the media
that work best for them Silkwood (2000).
Practical training activities are usually carried out in the workshop. This training cannot
be effective without adequate facilities. Davis (2011) confirmed that adequate training facilities
enhances skill development of students in a technical institution and sufficient workshop area
with lavatories, lockers or shelving for student personal items and books , adequate provision of
electrical facilities are necessary in the workshop and that these should be confirmed before the
commissioning of a school workshop. In stressing the importance of successfulness of
installation of workshop facilities, basic tools/equipment must be adequate for practical to be
meaningful. Davis continued that no vocational or technical training can take place without tools
and equipments. Davis attested that inadequacy of vocational equipment in skill related trades
makes It impossible for technical teacher to impact necessary practical skills which makes the
learning process simpler and motivating to the learner and that the inadequateness of tools and
machines has made graduates of technical institutions handicapped of practical skills. The
physical plant facilities available for learning experience in any technical institution explains the
index of evaluating the quality of practical skills acquired by its graduates.
Adaradege (2003) buttressed this fact by saying that the overall emphasis of development
plans in education more often than not, addresses itself to quantitatively issues. How many
classrooms should be built and how many teachers are needed to teach the students within a
projected period and from a limited specified sum of money? Yet the quality of education that
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our students receive bears direct relevance to the variability or the lack thereof of facilities and
the overall atmosphere in which this learning takes place
Okedara (2005) echoed the same conviction, when he said that the acceptability and
accreditation of any remedial education centre would have to be precipitated on the quality of its
staff, courses and facilities available at the centres, adding that it might be too tempting for many
proprietor to establish centres without all essential facilities just to glorify their names, then to
provide centre with all essential materials that could contribute to the academic success of the
learners. Adeola (2004) observed that a discernible trend in Nigeria today is the drive toward
modernity and for social, technological, cultural and economic development. Such a trend is
anchored generally to the belief the poverty and political weakness are intolerable liabilities , and
that through conscious efforts, we can realize fully more than ever before, our potentials. It will
then be disastrous if these aspirant and expectations cannot be realized fully, owning to lack of
inadequate provision of physical plant facilities in our educational institution.
Adeola further explained physical plant facilities as involving much more than just the
school buildings, although it is its central element. The physical plant facilities has been used to
include the centre site, its landscaping, playgrounds, and other land, classroom, corridors,
lighting, sanitary facilities, recreational facilities, furniture equipment as well as other
consumable and non-consumable supplies required for use in other to achieve instructional and
educational objectives. The acquisition of landed property, the instruction of appropriate
buildings and the provision of essential equipment and supplies enable us to create the congenial
environment and class atmosphere where learning can be made easy and significant. It is also to
enable meaningful teaching-learning situation to exist in our educational institutions. Miller
(2003) opined that there is a close relationship between school curriculum and facilities.
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Workshops were regarded as facilitating service to the process of instruction. Therefore, its
design, size, structure, adaptability and upkeep have impact upon the objectives and methods of
education. Miller further indicated that an inefficiently used building, a poorly kept building, a
building with unpleasant colourless rooms, on poorly maintained site, all inhibit the development
of a good educational programme, as well as reduce staff and student moral. Apart for
facilitating the implementation of educational programs, school physical plant facilities are also
required to cater for the social and psychological wellbeing of the users. This view appeared to
be echoed by Fabulu (2000) when he said that sense of belonging may be strengthened in the
child, if the schools physical plant is sound, functional and pleasing to the eye. School physical
facilities also have influence on the institution and the community. Perhaps it is worth
mentioning that in most continuing education centers, there is no room for library facilities as
well as laboratory facilities. Yet, continuing education center is supposed to be kind of remedial
centre, where students are expected to make up for what had been missed during the formal
education.
While agreeing with Olutola (2002) who observed that the principal has a significant role
to play in ensuring a purposeful utilization of the school site, it must be emphasized that there is
need to encourage and ensure that the institutions personnel use the buildings, as well as other
physical plant facilities in a most desirable way. To this effect, the teaching and non-teaching
staff should be motivated to be vigilant give immediate reports concerning deterioration in
plants, such as damages to window panes, leaks in roofs and cracks in wall as the teacher
constructed blast retraining module used in teaching-learning process to enhance performance
can be only succeed with decent physical plant in place. In addition, students have a major role
to play in ensuring proper use and upkeep of plants. They should be made to appreciate that the
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institution and its property belong to them. It is therefore, incumbent upon them to see that the
plants are properly used and maintained. Students should be brought up to always ensure that
they keep buildings toilets, chalkboards, and furniture free from defacements and obscene
writings. So also, they should be trained to always give prompt reports of deterioration plants.
Good maintenance practice on facilities have the desired effect on the performance of
trainee appropriate tools and equipment such as recovery machine, manifold gauge, vaccum
pump must not only be available, but must also be properly managed. Management according to
Balogun (2003) means to handle or arrange a number of people, things or situation to bring about
what one desire. It is the act or process of tactfully controlling o bringing various elements to
work together for some particular purpose. In vocational education, management is o crucial
task. This is why each teacher and other members of staff must manage students’ resources and
environment of the institution, to the institutional specific purpose. To manage all these things
effectively, one need to have a clear view what the nature of each is, and of their weakness as
well as their strength. Management is the carrying out of operations designed to accomplish aims
and effectuate the policies. This definition is in line with Bajah (2005) definition which
described management as social process entailing responsibility for the effective, economical,
planning and regulation of the operations of an enterprise, in fulfillment of a particular purpose
or task. Such responsibility involves decision and judgment in determining plans, and the
development of data procedures to assist control for performance and progress against plans.
Balogun (2003) recommended that in vocational education resource, manager should be
conversant with various skills needed to be developed in students through the use of teacher
constructed re-training module to improve performance. Strategies for acquiring the skill must be
developed, making available tools needed to imparting the skill ready. This involves high level
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of planning, coordinating, controlling budgeting, recovering and evaluation of the physical
resources.
Management of technical education includes planning, organizing, directing,
coordinating activities of human resources material, equipment, fund and maintenance of
facilities ties for effective transmission Psychomotive, cognitive and effective domain. Light
(2004) viewed management as the body of knowledge about managing. To him managing are the
planning, organizing, directing, coordinating and controlling men, materials money, so as to
ensure the optimum achievement of objectives. Management plays a tremendous role in
enhancing the quality and efficiency in vocational education. It adds an extra dimension to the
instructional programs when properly managed. Momoh (2005) classified equipments as one of
the non-human resources that should be managed in the workshop.
Schools workshops in most cases are constructed to serve many students for so many
years. Balogun (2003) reported that the large number of learners in the workshop and the
repetitive type of training experiences cause workshop equipment to become worm out or
damage much faster than the same equipment would be in the hands of competent trade men.
Since vocational technical education lays much emphasis on skill acquisition, school workshop
should therefore be adequately planned and managed in order to keep them in good working
conditions. Facilities can limit educational program if not well planned, but well planned
facilities will not only enhance the day-to-day learning but also pave way for lunching new
educational programs in any school. He further observed that facilities in vocational education
workshops are often intended to last for half a century or more and to serve both the present and
the future needs. Vocational technical education workshops contain the facilities and equipment
necessary for work and study. Because of this diversity of skills which students are expected to
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acquire in the workshop. It is therefore necessary that the workshop be properly organized and
managed. Several factors are involved in the workshop management and organization. Rebort
(2005) indicated some of the factors involved to include: The planning of facilities to provide
space for study and work, the organization of the work personnel to provide efficiently in the
care of the facilities and equipment and the evaluation of projects as means of maintaining
performance amongst others.
Reborto noted that the usefulness of the school workshop depends on what the teacher
makes out of it. Therefore skillful and intelligent use of workshop is necessary in technical
education. Onwuka (2003) states that, one of the reasons why some teachers do not use the
workshop in their instruction is that they lack the necessary skills to organize and operate the
workshop facilities and equipment. The effectiveness of teaching therefore depends on how well
the teachers can organize and manage their workshops. The same idea was shared by Storm
(2004) when he stated that the quality of technical instruction depends to a large extent on
effective teaching strategies
Teaching Strategies for Capacity Building in Refrigeration and Air-Conditioning
Teaching Strategy may be defined as plan and specific ways decided and employed for
the realization if a goal. Teaching is defined as a purposeful activity performed the teacher for
guiding directing and showing the right path to the learner in their pursuit for the realization of
the set teaching-learning objectives. Therefore teaching strategies according to Mangal &
Mangal (2012) is the plans, means and specific ways especially devised and employed by the
teachers for guiding directing and showing path to be learners for the realization of the set
instructional or teaching-learning objectives. Similarity Stone and Moris cited in Mangal &
Mangal (2012) wrote that teaching strategy is a generalized plan for a lesson which includes an
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outline of planned tactics required to implement the strategy and structure desired learner
behaviours in terms of objectives of instruction. Teaching strategy is more comprehensive in
scope than teaching method.
Mangal and Mangal continued by identifying types of teaching strategies to include
lecture strategies, tutorial strategies, demonstration strategies, description strategy, supervised
study strategy, narration strategy, exposition strategy explanation strategy illustration strategy,
programmed instruction strategy, role-playing strategy, recapitulation strategy group discussion
strategy, question-answer strategy discovery or heuristic strategy, problem solving strategy
project strategy, dramatic strategy, independent study strategy, role-playing strategy, assignment
strategy, excursion strategy, drill or practices work strategy, strategy of employment A.V. aid,
brainstorming strategy and computer-assisted instruction strategy.
Mangal & Mangal further provided factor that determine choice of teaching strategies to
include: Nature of the learners, Nature of the objective to be realized, Nature of the learning
experience to be provided to the learners, Nature of the available teaching-learning environment
or situation and the teachers own ability and proficiency
The choice of the teaching strategies to be employed in the module of capacity building
of refrigeration and air-conditioning technologist will depend on the above criteria’s. Since
refrigerator and air-conditioning technology is a skills Managal & Managal acknowledged that
teaching of skill requires the followings strategies as described below.
Demonstration strategy
Demonstration as a teaching approach refers to the visual presentation of practical work
related to the evidences or the action and activities and principles of a delivered lesson by the
teacher in the classroom, aiming to facilitate the task of teaching and learning.
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Discovery or heuristic strategy
Heuristic strategy of teaching is that strategy which involves our placing students as far
as possible in the attitude if discover or problem solver, the strategy which involves their finding
out instead of being merely told about things.
Project strategy
Project strategy is the outcome of the practical ideas propagated by Sir John Dewey.
“Whatever is to be taught should have a direct link with the actual happenings in life”_ this
central idea forms the origin of project method. The principles of correlation has been given in a
very practical shape through this strategy as it tries to impart education in all the subjects in an
integrated way by correlating then with the real life activities.
Problem solving strategy
Problem solving strategy, as a teaching strategy, may be defined as a strategy which
provides opportunity to the students for analyzing and getting solution to a problem in the basis
of the pervious stock of their knowledge enriched with the present means available to them, quite
indecently by the following some systematic steps and arriving at some basic conclusion or
results to be used in future for the solution of similar problems in identical situations.
Illustration strategy
Illustration as a teaching strategy stands for the use of the means and materials-verbal or
concrete-for helping the students to acquire correct knowledge of the presented material by
making it quite clear, interesting, intelligible or comprehensible. In this device, the teacher has to
elucidate, explain or exemplify represented facts and phenomenon by means of certain aid
material in a verbal or concrete form or both.
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Description strategy
Description as a teaching strategy refers to an act of representing an object, person or
event through words, oral or written in full form or shape for providing the learner its total
definite, mental picture. It is similar to narration in many ways. Both are the verbal
representation of person, object or event.
Independent study strategy
Independent study means the study to be done by an individual himself with his
independent efforts. As a teaching strategy independent study may be defined as an attempt on
the part of a teacher to persuade his students to pick up the path of independent learning resulting
in the development of the habit of acquiring knowledge or skills through his own independent
efforts.
Supervised study as a teaching strategy
Supervised study means the study performed under supervision. In actual practice, when
the students engage themselves in some learning activities under the properly organized
supervision of their teacher, the phenomenon is labeled as supervised study. It may take either of
the two forms-individual or collective. This means self- study or groups study when performed
under the proper supervision of a teacher or a group of teachers make the shape of supervised
study.
Drill work strategy
Drill work, as teaching strategy is said to be one of the most significant and indispensable
devices employed by the teacher in his teaching-learning process of replacing into the minds of
the students the materials already learnt by them. Thus, in the delivery of a lesson it comes after
the presentation of the whole material or a part or unit of it in form of practice or revision of the
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learned materials. In all aspects, drill work is a teacher-initiated and teacher-directed classroom
practice or exercise work performed by the students which aims for the perfection of a skill or
performance of the material to be retained in the memory of the students.
Assignment strategy
The meaning of the work assignment is allotment. In this sense, the terms assignment
strategy of teaching stands for the strategy of which students are assigned or allotted some
special duties for carrying out theoretical study or practical activities on individual or small
groups basis aimed at the realization of the stipulated teaching-learning objective.
Tutorial strategy
Tutorial strategy is a strategy of teaching in which one or a small group if students
(tutees) are provided personalized an individualized education from a tutor. As a teaching
strategy, it may be used to teach all the subjects of the school curriculum as well as providing
training and experiences for the development of many aspects of one’s personality. It is
application to the learners of all ages and all levels of ability and potential.
Brainstorming strategy
This strategy can be used with a group to explore a number of concepts related to a
solution or situation of a problem without passing any judgment or censure. This approach is
especially useful for the development of higher cognitive abilities like creative imagination,
reflective thinking and problem solving. It is helpful in the attainment of the learning objectives
associated with the affective domain.
An instructional strategy that perhaps requires special comment is the teacher and fellow
class mates as a medium of human resource that is all too frequently overlooked in self-
instructional systems. Self-instruction need not be dehumanized by solitude. Although students
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may be free to proceed at their own pace they should be encouraged to interact with fellow
students and with their teacher. This personal contact can clarify the subject matter; develop
positive attitudes and values; answer questions raised by material in the module and enrich the
student’s interests. Modules have the further characteristic of providing opportunities for a wide
variety of methods of instruction, varying say, from straight out reading, through problem
solving and discussion sessions, to practical work and the exploration of media. In this way
unlike formal programmed learning, they avoid monotony and maintain interest and motivation
(Silkwood 2000, John 2005).
Trainers or teachers of practical skills adopt several models to train individuals for the
mastering of skills. Training methods can also be classified under broader terms as cognitive or
behavioral. The adoption of the demonstration and project model is bound to make training
effective and improve the performance of trainees in their places of work. Emphasizing on the
importance of performance Osinem and Nwoji (2005) submitted that training may not be
completed until the trainees have used the skills being taught to benefit themselves or other
positively. Performance therefore is the result of a trainee’s action that is observable and
assessed to see whether the trainee has successfully completed a task or a job.
Joseph (2013) Emphasis that small grouping for instruction is the most efficient approach
to teaching and that this practice can be individualized through the provision of different
activities based upon individual student need. Joseph further stated that the approach have the
advantage of more efficient use of instructional time, effective student management, increased
instructional time, increased peer interaction and increased generation skills.
Awofula-Efebo cited in Vikoo (2003) described role-play as method of using games as a
teaching method; a problem is selected delineated by rules, acted out through competition and
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discussed by the teacher and students. The method involves five essential steps are: The
identification of a suitable problem situation, Assignment of roles to students who can act out the
roles of those involved in the problem situation; Making of rules by the teachers to guide the
role-playing, Actual role-playing; and Group discussion of the roles acted out by the teacher and
student.
According to Joyce and Weil (1980) cited in Vikoo (2003) this method gives
opportunities to explore together feelings, attitudes, values and problem-solving strategies. This
method is extensively used in religious studies as well as some other social science subjects, at
the end of the dramatization or computer simulation. There is group discussion about the lesson
by the students and teachers.
Role-playing is adapted to a variety of situations, social situations that requires
alternative courses of action to solve problems. According to Vikoo (2003) role-playing can also
be used to demonstrate concepts and attitudes required in courses that are content- centred; for
example studying novel, play, historical events.
Vikoo further identified teaching strategies that are recommended for psychomotor
development. Psychomotor development methods are activity-oriented methods which aim at
developing in students’ knowledge of procedures, their manual dexterity. The teaching strategies
recommended by Vikoo includes demonstration; laboratory/Experimentation method, project
method, inquiry/discovery method, process approach, mastery learning approach, programmed
learning approach, Dalton plan/ assignment and microteaching method.
Demonstration is seen by Vikoo as the process of presenting or establishing facts or
principles. It is a procedure of performing or doing something in the presence of others either as
a mean of demonstrating the performance of a skill so that the observers can perform the skill
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themselves. The characteristics student involvement is listening, watching and observing.
Vikoo further outlined the function of demonstration techniques to include illustrating a fact or
principle, visualizing a process, show materials or specimens, portraying methods or techniques,
creating a problem situation and evaluating students’ achievements.
Laboratory method according to Pella cited in Vikoo (2003) is an instructional method in
which cause and effect, nature or property of any object or phenomenon is decided by individual
experience generally under controlled conditions. Pella identified the function of laboratory
exercise as a means of securing information, a means of determining cause-effect relations, a
means of verifying certain factors or phenomena, a means of applying what is known, a means of
developing skills, a means of providing drill, and a means of helping pupils learns to use
scientific methods in solving a problems and means of carrying on individual investigation.
Vikoo (2003) describe project method to be a method that helps students to work together
from an initial stage of manning through stages of development, implementation and evaluation.
He further said that the method involves choosing a subject, problem or topic, deciding what is
needed to carry it out, carrying it out to the best of one’s ability.
Borich (2011) proposed that teachers who build their instruction around projects provide
learners with an environment ideally suited for self-directed inquiry and that teachers must do
this in ways that guarantees learners that their success relies on factors they control. He further
outlined aims of project based learning to be to communicate to learners the importance of the
learning process and not just the project, to help them set goals, and to use instructional grouping
to elicit the cooperation of others in completing the project.
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Evaluation Techniques in Capacity Building in Refrigeration and Air-Conditioning
Mangal & Mangal (2012) explains evaluation techniques as ways and means measures
and assess the extent to which the desired behavioral changes have taken place in the learner.
They identified the following to include evaluation techniques; Oral tests and examination,
Practical test and examination, written test and examination consisting of essay and objective and
start answer type question and Techniques and devices such as observation, discussion,
questionnaire, inventory, interview, checklist, attitude scale, rating scale, case study, project
techniques assignment, project work, and creative and production of the students.
Mangal & Mangal (2012) categorized evaluation task as criterion reference and norm-
referenced. They distinguished both by saying that criterion-reference has an accepted level of
performance called mastery level well fixed before the beginning of the actual teaching and at
the end of the instructional period an attempt is made to know the extent to which the predator
minded level of performance in mastery level has been achieved by the individual learner, the
researcher will adopt the criterion reference test because in developing module Dick and Carey
(1979) in theory of instructional design supported by Kemp (Kemp Instructional Design Model,
2012) stressed that in developing instructional assessment instrument, purpose of entry behavior
practical item/practical problem must be stated and the performance objective should consist the
condition or criteria of expected level of mastery.
In selection of the appropriate evaluation techniques, Mangal & Mangal cited earlier state
condition that guides decision about adopting particular evaluation techniques to depend on the
follows: Objective or objectives of teaching-learning, Contents or the learning experiences
provided to the learner, the methodology and strategies adopted, The behavioral domain in which
the behavioral changes are to be measured or assessed, The purposes such as diagnostic,
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formative or summative or providing information, feedback, grading etc., The level, memory,
understanding and reflective of the organization of teaching-learning, The nature if the
evaluation techniques or techniques for serving some particular or required purposes.
Mangal & Mangal in selecting evaluation techniques that is appropriate for measuring
and assessing the teaching-learning outcome that is related to the behavioral domain of
psychomotor, Mangal & Mangal recommended the observational techniques because it is proper,
reliable objective recording of the observed behavior and performance, the checklist rating scales
are helpful. Therefore the researcher will adopted the observation techniques because acquiring
mastery skill in refrigeration is a psycho motive skill since it has to do with reflex movement to
skill movement. The observation evaluation techniques uses instruments such as rating scales,
checklist and concluded by recommending that the performance level can be represented by out-
standing (0-80 above) performance above average (A-70-79) average (B-60-69) below average
(C-50-59) and inadequate (less than 50).
Evaluation is designed for enhancement of teaching and students learning. Bigs and
Tany cited in GIE (2013) attest that your evaluation and document how well, your teaching
enables your students to learn in your particular context and that in curriculum model design,
where aims and objectives, assessment, teaching and learning activities are usually align
constructively.
Wendy (2002) pointed out that appraisal methods or techniques should be based on the
objectives of the training procedure and should meet the demand of the stakeholders. The
evaluation for competency according to Wendy should be able to answer questions whether the
competencies have been learned and whether the learning has been realistic toward improved
performance.
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Criterion referenced test is applied to learn whether the criteria stated in an objective.
Evaluation according Akaninwor (2000) is system method that is used to determine level to
which educational objective are achieved through the performance of the learner. He further
stated that evaluation is carried out the reason of determining the suitability of the students for
the world of work, to seek placement for the students in industrial and commercial establishment
which require their services and to prepare recommendations for those wishing proceed for
further training. Akaninwor referred to test as the instrument that is utilized to determine
realization of educational objectives. Akaniwor further identified test to be of two types, namely
norm reference and criterion reference tests. Criterion-referenced assessments are composed of
items or performance responsibilities that directly, measure skills, described in one or more
behavioral ideas and identifies types of criterion-referenced test to be entry practice test,
behavior test and post-test.
An important characteristic of modules is that they provide continuous feedback to
students on their performance and especially on their progress towards achieving objectives.
They do this by building in at frequent intervals in-text questions, checklists and quizzes and by
immediately providing answers to these so that students can themselves; check up on their levels
of knowledge, understanding and skill. Immediacy is important; a delay in providing feedback to
a student on his/her performance reduces the level of learning. Modules generally require
students to make regular written responses and the correct or “model” answer is then provided
on the next page. Students who fail to answer correctly quickly see where they went wrong and
can return to appropriate learning characteristics of modules and go a long way to explain their
superiority over conventional teaching. In large conventional classes it is almost impossible for
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each student to receive instant feedback on the quality of his/her works from moment to moment
(Farooq cited in Silkwood 2000).
Closely related to the previous point is the question of reinforcement. By reinforcement
in this context is meant consolidation of learning through reward for success. Self-instructional
modules, like programmed learning, use reinforcement of correct responses to shape behavior.
They do so, however, without using the standard- sized small steps or frames of the traditional
formal programme. Students are more in control of the size of each learning step. What modules
have in common with programmed leaning, however, is that students can see instantly if they are
right or wrong. If they have been conscientious in studying the material they are usually correct,
satisfaction gained from success provides rewards, which are the basis of reinforcement. As in
the case of feedback, reinforcement is the most effective if it is immediate and module provides
this immediacy (Rasait 2005).Rasait continued by saying that clearly the type of reinforcement
gained from modular instruction lacks the human warmth and empathy gained from the special
recognition, which may be obtained in the conventional classroom. On the other hand, a student
using modules is more frequently and systematically rewarded than in a large class. In addition
the teacher is free from being the main source of information to become a counselor and learning
guide. He or she can interact with students more frequently on a one-to-one basis. In this way
modules allow more humanistic type of reinforcement to be significantly increased.
Torraiba in Silkwood (2000) said that the most effective modules utilize a system of
student assessment, which requires mastery of the objectives. By mastery is meant achievement
of a pre-set standard as judged by a prescribed criterion or level of performance. It is assumed
that students will master one module before proceeding to the next in a sequence. This system
ensures that students will succeed and it minimizes failure. It helps to ensure that all the key
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material has been understood or that necessary skills have been attained before students move on
to new work. Torraiba continued by saying that modules are sometimes units within modules,
usually conclude with a carefully structured mastery test with items corresponding one-to-one
with the objectives. Grades as such are not important. What is important is that students can
check off which objectives have been attained and which have not been attained. They can then
retrace their steps to bridge any obvious gaps in their preparation.
The concept of mastery learning has been developed in detail by the psychologist Bloom
cited in Silkwood. Bloom strongly contended that most students (perhaps 90 percent) can master
what they have to teacher them. Bloom claimed that it is the task of instruction to find the means
to enable students to master a particular subject. It is a matter of finding the most appropriate
methods and materials, which will enable the majority of our students to master the objectives.
Unfortunately, many teachers have been conditioned by the normal curve and to the 33
percent passing grade. This is called a normative or norm-referenced approach to assessment as
it compares each student with each other student .Grades is assesses according to class norms.
This method is designed to detect differences between students and often failures are simply
defined by rank order instead of failure to learn essential ideas. This approach is recommended
only if the best students have to be selected for scholarships or for competitive places in other
institutions. The method is, however, counterproductive to effective learning. In contrast,
modules by insisting on mastery, utilize a criterion-referenced approach to assessment. They
encourage each student to reach an agreed standard on a set of criteria. Each student is
challenged to achieve in his/her own right irrespective of what may or may not achieve
(Acelajado 2005).
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It is necessary to evaluate the performance of skill holders to ascertain whether the
desired training has occurred. Evaluation is therefore carried out to determine the extent to
which training objectives are achieved or to determine if the trainees have measured and
developed the ability to use skills and idea contained in the training.
Learning outcome is evaluated in diverse ways. Instructors, especially those of skill-
oriented courses generally employ observation more frequently to evaluate their subjects.
However, Osinem (2005) identified other techniques, namely: oral questions, discussion,
demonstration, project method and procedure testing. He remarked that each of the techniques
possess distinct characteristics that make it especially useful for measurement of a particular kind
of performance.
Evaluators use several performance evaluation tools to perform their job. The tools
according to Chalmers (2003) are checklist, rating scale and evaluation questionnaire. He
remarked that the tool used must closely represent an actual work situation the examinee is
expected to encounter at the end of the training experience. In this study, the rating scale was
used to evaluate the performance of youth (trainees) in refrigeration and air-conditioning
practice. The use of the rating scale either in natural or simulated setting is a very useful
technique for gathering data about trainees’ performance and about their affective behavior.
Based on this, the researcher used the rating scale because it is provided with attributes, the rater
will assess and the rate is merely to indicate the degree to which a particular attribute is
influenced by the trainee. In his own submission, he remarked that the use of rating scale
enables the user to indicate the quality of what is being rated. Notwithstanding the importance of
the rating scale, its use may likely be influenced by irrelevant factors in rating performance.
Such factors which could introduce elements of bias in scoring or rating performance were
outlined by Chalmers. They include: error of severity; the tendency to rate individuals too low on
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all characteristics, generosity error; the tendency to give high grades than necessary, among other
factors.
Evaluation of developed module is carried out because in spite of the care in the initial
design of a module no one can be certain of its true educational effectiveness. Kubiszyn and
Borich in John (2006) are of the opinion that in considering this issue two general aspects must
be clarified. The first involves the important distinction between formative evaluation and
summative evaluation and the second concerns the general factors that need to be assessed in
trailing the materials. Formative evaluation is undertaken during the development stage of the
module. The results of the developers alter the design of the materials to make them more
effective during the formative stages i.e. before the material is produced at larger for general use
while Summative evaluation occurs after the design has been completed and the materials been
produced and used. It is concerned with issues such as the comparative effectiveness of
comparing resources; to check on whether established resources are in used for revision; or to
make decision about the relative effectiveness of say, traditional or innovative approaches. The
results of summative evaluation are used to help in decision about whether or not a program or
particular ongoing resources should be deleted, modified, or adopted.
The essential purpose of evaluation is to validate the module. That is to establish, that it is
educationally effective with a representative group of students for whom it is intended. The
process of formative evaluation involves the collection of more and more data from tryout with
colleagues and students; the feeding back of that data to the designer and the continual
modification of the material so there is a closer and closer fit between the actual materials and
the ideal material needed for the designated group of students to achieve the specific objectives
of the module.
During the evaluation of module, data need to be collected on the following:
Appropriateness of the purpose, aims and objectives of the total program (curriculum grid) of
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which the specific module is a part, appropriateness of the purpose, aims and objectives of the
specific modules, the overall effectiveness of the module. In other words does it actually work?
The key issue of the course whether or not the learning activities lead to the achievements of the
objectives, the quality of technical aspects. Have the principles of design been applied
effectively? Is the learning not only effective but also efficient and interesting? Are the activities
in text questions, the layout, and the style and so on the most suitable for the students concerned?
Administrative and other issues relating to implementation.
Theoretical Framework
For instructors and trainee to achieve effective learning experience, instructional
developers consider some essential theories in order to understand both how learning occurs
(learning theory) and what action is needed to facilitate effective learning (Reiguluth, 2000). As
such, learning theories and curriculum theories are important to be considered in the process of
development of module. Ertmer and Newby (2011) outlined three important reasons for focusing
on learning theories as; Learning theories are a source of verified instructional tactics, strategies
and techniques. Learning theories provide the basis for intelligent and reasoned strategy
selection. Integration of the selected strategy within the instructional context is critically
important. Therefore, gaining a general background and basic understanding of appropriate
theories can help in the overall development of module. It is worthy to consider the theory of
Skinner on operant conditioning, Taba’s model on curriculum development, and Savickas career
development theory for development of capacity building module.
Taba’s Model of Curriculum Development
Taba (1962) model is a linear sequence that advocated an inductive approach to curriculum
developing study, that development should start with the specifics and build up to general design
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as opposed to the more traditional deductive approach of starting with general design and
working down to the specifics. It is based on a specific step by step plan, with specific goals and
objectives, with activities that coincides and are evaluated with the stated objectives. Taba
believed that the curriculum should be organized around genetized learning objectives which
enable students to discover principles that will enable them to be successful.
Taba’s model is made of seven steps namely; diagnosis of needs, formulation of
objectives, selection of content, organization of content, selection of learning experience,
organization of learning experience, and determination of what to evaluate and means to
evaluate. Taba’s model is relevant to this study in all the seven steps. Diagnosis of needs was
carried out through preliminary study to identify the gap in skills of technologists in refrigeration
and air-conditioning. The information obtained was used to formulate the objectives, content,
training facilities and teaching strategies. The model also guided the study to determine
evaluation techniques.
Figure 4. Taba’s Curriculum Model
Diagnosis of the needs
Formulation of objective
Selection of content
Evaluation
Organization of learning experience
Selection of learning experience
Organization of content
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Skinner’s Operant Conditioning
Skinner (1974) developed learning theory known as operant conditioning. Skinner
believed that in operant conditioning, most of the important concepts of behavioral control could
be revealed and examined. The following principles are deduced from operant conditioning
namely; principles of reinforcement, principle of active participation, principle of successive
approximation (shaping) and principle of knowledge of result or feedback.
The principle deduced is important in the integration of immediate feedback after
assessment, in order to motivate the trainees. Principle of active participation will be employed
in the teaching strategies by including activities, this will enable full participation of trainee. The
modules material will be sequenced in logical steps, strict time will be avoided to give way to
individual mastering of skill before escaping the module. Principle of shaping will be utilized in
the content to ensure that the learning task proceed from simple to complex in small steps.
Self-Concept Theory Career Development by Savickas.
Savickas (1999) stated that the process of career construction is essentially that of developing
and implementing vocational self-concepts in work roles. A relatively stable self-concept should
emerge in late adolescence to serve as a guide to career choices and adjustment self-concept
continue to evolve as person encounters new experience and progress through the developmental
stages.
Career development theory of Savickas (1999) identifies developmentally appropriate
tasks and interventions at different educational levels and focuses on decision making, self-
knowledge, occupational information, planning and problem solving through four intervention
methods. These four intervention methods are career orientation, teaching skills for planning and
exploring career possibilities, coaching of career management techniques, and role rehearsal of
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job problems. The major task according to this approach is increasing choice awareness by
seeking information, then planning to make the choice. This can be accomplished by inspiring
students to explore and participate in the widest possible range of activities.
Career developmental theory is appropriate for the study because using the capacity building
module to train graduates of polytechnics, or those that are still in the school, their skills in
planning and exploring career possibilities and development of appropriate task in solving
practical problems on refrigeration and air-condition plants will be enhanced.
Related Empirical Studies
Several scholarly papers have been reviewed and in addition, some empirical studies
related to the study were reviewed. One of such studies is that conducted by Selcux (2010)
investigated the effects of learning module on pre-service teachers’ achievement, approaches and
attitudes towards learning physics and adapted a quasi-experimental pretest-posttest design with
a total of 25 students measuring in mathematics. The results indicated that the learning module
method not only encouraged the students’ deep approach to learning, but also improved interest
towards the physics course. The study recommended teachers to review the potential benefits of
learning module instruction. There is a relationship between the work and the present because,
the importance of module is emphasized but there exist a gap because there was no module
development specifically for capacity building in refrigeration and air-conditioning.
Ibrahim, Evdal and Mustafa (2009) conducted study to investigate the effects of learning
module instruction on University Students performance of Quantitative and Conceptual problems
in Gas concepts. None equivalent pre-test- and post-test control group design was used. Two
groups comprising experimental group (40), and the other control group (38) took traditional
instruction. The analysis of the results showed that students in experimental group had better
performance on conceptual while there was a change in students performances of quantitative
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problems. The study recommended that learning module instruction should be adapted since it is
useful in laboratory teaching since it includes a range of activities such as comprehension,
collaboration and analysis of the events, collecting information, developing hypothesis and
analyzing it and making experiments. There is a relationship that exists in the study and the
present because of the teaching strategies that the module contains which serves a component of
the present module but there exist a gap because there was no module developed and test was not
carried out on refrigeration and air-conditioning technologists.
Mercede, (2009) Mercede carried out studies to develop and evaluate a recommended set
of modules in principles and method of teaching. The purpose of his study was to access the
characteristics of the components of the modules. The method utilized was descriptive survey
method, the respondents were faculty members currently teaching and have taught principles and
methods of teaching in the past two academy year and forty two students that have been exposed
to the use of module. The instrument used was check list developed by the researcher on the
characteristics of the modules. The findings revealed that the module components characteristics
met the requirement of the authorities on teacher education. There is a relationship between
Mercede’s, work and the present work because he developed and evaluated a set of module in
principle and method of teaching which is similar to the present work. There exists a gap to be
filled because the module developed was not used for development of capacity building in
refrigeration and air-conditioning. Secondly criterion measures were not use to ascertain the
validity of the module.
Blacksburg (2008) on Design, Development and Evaluation of a Learning module for
teaching Digital Technology skills. The study adopted developmental research approach. Where
the module was designed and developed and given to expert reviewers for criticism, after the
final criticism, the module was given to teachers, teachers were given time frame to utilize the
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module, evaluation form for teachers and students were developed and given to the teacher to
use. Linear formative evaluation was used to assess teacher’s utilization. The findings revealed
that the module was at initial time difficult to teachers to implement but the recommendation
suggested that teachers should be trained to use a learning module approach for professional
development in order to gain exposure to the process and get them accustomed to the
environment. But the study did not compare the effect of the learning module approach on
students’ performance. The work has relationship with the present work because a module was
developed, using developmental research method and it was validated through trial-test but there
exist a gap because the module was not developed for teaching refrigeration and air-
conditioning. Secondly, the method used for validating module was not trial-tested.
Martin, West and Bill (2008) carried out study on incorporating learning module
strategies to develop learner autonomy and employability skills in sports science undergraduates.
Three scales were used to ascertain motivation, self-esteem and locus of control. There was a
pre/post-test on participants of two groups. The result was analyzed using the Wilcoxon signed
rank test and a significance level of P<0.05 was set. The findings indicated that the short course
of learning module was successful in developing learner independence and other key
employability skills alongside the application of content knowledge. The study concluded that
learning module appears to be an effective learning and teaching strategy. There exist a
relationship between the study and the present study because, the study was carried out to
investigate strategies to develop learner autonomy and employability skills through the use of
module, and the present study is aimed at building the capacity of refrigeration and air-
conditioning technologists through the use of module, but there is a gap because, the module was
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not use to find out strategies to develop capacity of refrigeration and air-conditioning
technologists.
Onuka (2008) developed skills training modules for enhancing youth participation in
regulated cassava processing occupations in South East Nigeria. Research and Development was
used for the study. The instruments were face validated and the rating scales were also validated
using Kendall’s coefficient of concordance. Trail test was used to test the hypotheses of no
significance difference at 0.05 level of significance. The result confirmed some skills and
facilities to be relevant for the module development and it was also confirmed that the module
was appropriate for training because those trained with module performed to NAFDAC
regulatory standard. The work of Onuka is similar to the present work because research and
development approach was used, the instruments were validated and the module will be trial-
tested. But there is a gap because, the training facilities and skills identified and used are not
relevant to development of refrigeration and air-conditioning capacity building module.
Orthan and Ruhan (2007) conducted a study to determine the effects of learning module
in science education on students’ academic achievement and concept learning. In the study, both
qualitative and quantitative research methods were utilized. Quantitative data were obtained
through the pre/post-test, treatment-control groups test model. Qualitative data were obtained via
document analysis. The research study was conducted on 50, students 7th grade students. The
treatment process took 30 class hours in total, three measurements instrument were used, open-
ended questions, an achievement test, and an attitude scale for science education. The subject
matters were taught on the basis of learning module in the treatment group, traditional teaching
methods were employed in the control group. The findings revealed that learning module
positively affected students’ achievement and their approach towards the science courses. The
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study is similar with the present study in that validity of use of module was carried out by
checking students’ performance. But there exist a gap in that there was no systematic approach
for the module development.
Anuaja (2005) carried out a study to; Develop Work Skill modules for effective
management of school farms by Agricultural Science teachers in secondary schools in Abia state.
The questionnaire was the instrument used for collecting data from 160 respondents made up of
male and female agricultural science teachers in Abia state. The data collected were examined
using the mean and standard deviation to answer the research questions, and t-test statistics for
testing the null hypothesis. The findings from the study revealed that 32 work skills were
required for affective management of the school farm. The work skills were 9 in planning, 8 in
organizing, 7 in the directing of school farm activities while 8 were required in controlling
school farm activities. The result of the null hypothesis tested showed that there was no
significant difference in the mean rating of the responses of male and female agricultural science
teachers on 29 work skill items required for effective management of school farm in Abia state.
The information provided by the respondents was used to develop work-skill modules for
effective management of school farm. However, the modules were not trial-tested. It was
recommended that the work skill modules developed by the study could be produced in manuals
for training secondary school teachers on short course basis for better performance on the school
farm operations. There is similarity between the work of Anuaja and the present because skills
needed were identified which was used for the development of work skill modules for
management of school farm. Similarly, the needed skills in refrigeration were also identified
through research F that will be used to develop refrigeration and air-conditioning capacity
building module. There exists a gap because the module was not try-out for validity and the
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skills identified cannot be used for development of module for training refrigeration and air-
conditioning technologists.
Bouma (2002) under the International Energy Agency (IEA) Heat Pump Centres
conducted a study to gather and analyze information on refrigerant recovery, reclamation
recycling, and disposal guidelines and practices being pursued in major market located in Asia,
Europe and North America. The study aimed at comparing and contrasting the effectiveness of
different methods and where possible, to quantify subsequent reduction in emissions and
environmental benefits. The findings revealed that most countries surveyed have national
programs and policies in place with respect to prohibition of the release of ozone depleting
substances, and similar certification requirements exist for the recovery, reclamation and
recycling of certain refrigerants. The study of Bouma is similar to the present study because both
studies are geared toward solving the problem of emission of ozone depleting refrigerant but
there is gap because the study of Bouma did not provide any practical ways of improving the
skills of refrigeration and air-conditioning technologists of which the present study intend to
provide by developing a capacity building modules for refrigeration and air-conditioning
technologists.
Summary of Review ofRelated Literature
The related literature reviewed covered conceptual framework which includes
refrigeration and air-condition technology, polytechnic education in Nigeria, development of
modules, capacity building. The conceptual framework reviewed helped the researcher to
identify the problems in refrigeration and air-conditioning technology, skills needed for capacity
building, roles of polytechnics in providing the needed skills to technologists for reduction of
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venting ozone depleting refrigeration into the atmosphere. Capacity building to be given to
technologists will equip them for employability and environmental protection.
Literature reviewed on development of module helped the researcher to identified the deficiency
needs, task analysis, planning procedures, and how to articulated all the components of the
module. Literatures reviewed on the objectives content, training facilities, teaching strategies,
evaluation techniques helped in identifying the appropriate objectives, content, teaching
strategies, training facilities, and the necessary evaluation techniques to be incorporated in the
module.
The following theories were reviewed, Skinner operant conditioning theory, Taba’s
model of curriculum development and self-concept theory career development by Savicks.
Theory of Skinner revealed that lesson for effective mastering skill need to be broken down to
small steps. The objectives be stated in clear terms. Selection of teaching strategies and
evaluation should be carried out at the end of the lesson for the purpose of reinforcement. Taba’s
curriculum development revealed that seven steps are involved in curriculum development
processes. The steps includes diagnosis of needs, formulation of objective, selection of content,
organization of content, selection of learning experiences, organization of learning experiences,
and evaluation. The self-concept career development by savicks revealed that career
development involves, identification of appropriate task, self-knowledge, occupational
information and problem solving through intervention. The study adopted all the principles
derived from the reviewed theories because of the relevance to the study. None of the related
empirical studies reviewed revealed that there has been any work done on development of
capacity building modules for refrigeration and air-conditioning technologists. That was the gap
filled by the study.
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CHAPTER THREE
METHODOLOGY
The chapter presents the method to be used in carrying out the study. The method
includes the design of the study, population of the study, area of the study, sample and sampling
technique, reliability of the study, validity of the instrument, instrument for data collection, data
analysis, and development of module and validation of the module.
Design of the study
The study adopted Research and Development (R&D).Borg & Gall (2007) attest that
when the use of research findings is utilized in designing and developing new programmes,
materials, that will provide knowledge and skills, research and development is appropriate.
System Approach Model in research and development by Dick and Carey cited Borg and Gall
(2007) outlined eight steps that are usually involved in system approach model research and
development to include:
1-Identification of goal of instructional program
2- Identification of specific skills
3- Identification of learning tasks and procedures
4- Translating goals into specific objectives
5- Development of assessment instrument
6- Development of instructional strategy
7-Development of instructional materials
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8-Evaluation. In this study of development of capacity building module for refrigeration and air-
conditioning technologists, the eight steps of Dick and Carey was modified into five steps, which
includes:
1-Determination of goal for capacity building for refrigeration and air-conditioning technologists
2-Development of instrument
3-Validation of instrument
4- Need Assessment
5- Development of module
Therefore, Research and Development (R&D) was appropriate for the study because, the
study developed a new programme and material that is effective for building capacity of
refrigeration and air-conditioning technologists
Area of the Study
The study was carried out in south-south geopolitical zone, Nigeria. South-South comprises of
Rives State, Akwa Ibom state, Edo state, Delta state, and Bayelsa state. There are many
industries, such as Petro-chemical, Liquefied Natural Gas Industry, Fertilizer Industry, Hospitals,
Oil Production Industry, Refineries, Agricultural Farms that their activities solely depend on
refrigeration and air-conditioning. Most of these refrigerators and air-conditioners contain ozone
depleting refrigerants that requires expert technologists for installation, trouble-shooting,
repairing and commissioning without emission of ozone depleting refrigerants into the
atmosphere. Secondly there are graduates from Polytechnics who doo not acquire the needed
skills by the industries for refrigeration and air-conditioning technologists that might want
capacity building for upgrade of skills needed by industries.
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Population for the Study
Phase 1: The population for the study at phase (1) was 93 practicing technologists,
technician and teachers of refrigeration and air-conditioning. These include 34 technologists, and
45 technician of refrigeration and air-conditioning working in industries, also 14 teachers of
refrigeration and air-conditioning teaching in technical college, craft development centre,
polytechnic in south-south. The number of technicians, technologists and teachers were obtained
from records of National Association of Refrigeration and Air-conditioning practitioners
(NARAP) and Ozone Programme Implementation and Management Unit (OPIAMU) see pg…..
Phase II: The phase (II) of the study was the validation of the capacity building module.
The population was 25 final year Higher National Diploma students of Federal Polytechnic, Offa
that was used for the try-out at the validation stage of the developed module. The polytechnic
was chosen because there is trained refrigeration and air-conditioning lecturer and facilities for
try-out of developed module.
Sample and Sampling Technique
The entire population was studied. All the 93 population on phase( I ) and (11) was
studied because of the manageable of the population and its unique characteristics. The choice
by the researcher was supported by Gall et al, (2003) and Uzoagulu (2011) both accepts that
entire population can be studied when the characteristic is unique and the distance is convenient
to the researcher.
Step I: Identification of Goal for Capacity Building Module for Refrigeration and
Air-conditioning Technology.
Preliminary study was carried out to determine skills by refrigeration and air-
conditioning structure 4 – point scale questionnaire, were administered to technologists,
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technicians and workshop supervisors of refrigeration and air-conditioning, working in the
industries. Decision for the research question was based on cut-off point of 2.5. In other words
any item with 2.5 and above was considered as agreed and was accepted while mean below 2.5
was taken as disagreed. Result revealed that refrigeration and air-conditioning technologists need
skills in leak detection, evacuation of contaminants, trouble-shooting electrical panel, recovery,
recycling, retrofitting alternative refrigerants and commissioning, hence the goal for this study
was identified to be development of capacity building modules for refrigeration and air-
conditioning technologist (Ogbuanya and Kpabep, 2013).
Step II: Development of Instrument
Phase(1) -Relevant literatures relating to the study were reviewed and used for development of
instrument for the study at Phase (I). One set of questionnaire titled, Questionnaire for
Development of Capacity Building Module for Refrigeration and Air-conditioning
Technologists, was developed and used to obtain data at the phase 1 of the study. Questionnaire
items were developed in-line with each of the research question. Literatures were reviewed so as
to obtain relevant items on each research question. The questionnaire was divided into section A
– F. Section A, sort for personal data of the respondents, section B, sort for respondent opinion
on the objectives of the module with 10 items, section C contains 96 items on contents. Section
D contain 40 items on training facilities, section E, contains 23 items on teaching strategies and
section F, contains 13 items on evaluation techniques. The instrument was structured on 5 point
likert scale with the following response options;
Strongly Agreed (SA) – 5
Agreed (A) – 4
Undecided (U) – 3
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Disagreed (D) – 2
Strongly Disagreed – 1
Respondents were requested to check response option that is acceptable for inclusion in
the development of capacity building module for refrigeration and air-conditioning technologists.
Phase( II)- instrument used for data collection was instrument title, Refrigeration and
Air-conditioning Psychomotive Rating Scale (RAPRS). The instrument contains 57 mastery skill
specifications and another known as self-check test for self-training. The (RAPRS) contains 57
mastery skills along with sequential observable tasks to be assessed. The tasks were produced
using the content of each skill specification and specific objective broken into sequential step.
The following were the components of the rating scale.
Skills to be evaluated followed with evaluation criteria as:
Low performance (4) – 1
Moderate performance (MP) – 2
High performance (HP) – 3
Very High Performance – 4
Raters were requested to use the outlined skills after training as observable criteria for
evaluation for competency in refrigeration and air-conditioning technology.
Step (111) - Validation of the instrument
Questionnaire for Development of Capacity Building Module for Refrigeration and Air-
conditioning Technologist (QDCMRAT) was validated by three experts comprising, three
lecturers of University of Nigeria, Nsukka, comprising two lecturers, in the department of
Industrial Technical Education and one in the department of Mechanical Engineering. The
lecturers were requested to ascertain the suitability of the objectives, content, training facilities,
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teaching strategies and evaluation techniques. Secondly ,two refrigeration and air-conditioning
experts working with SAIPEN CONTRACTOR in Port Harcourt were requested to ascertain the
suitability of the module content, validates were requested to delete, add items as appropriate,
ascertain adequacy and make general comment for improvement of the instrument to which the
final draft of the instrument was produced.
Phase (11) The developed module for capacity building of refrigeration and air-conditioning
draft was validated by 3 experts. The experts are lecturers of refrigeration and air-conditioning in
the department of Mechanical Engineering, Ken Saro-Wiwa Polytechnic, Bori.The validates
were requested to assess the whole draft and delete, add appropriate words and make general
comments for the improvement of the module.
Phase (III) Reliability of the Instrument
The internal consistency of the instrument was determined using cronbach alpha method.
The questionnaire was distributed to 20 respondents, comprising 18 technologists and
technicians involved with installation, repairing and commissioning refrigerators and air-
conditioners. Also 2 lecturers teaching refrigeration and air-conditioning, at Federal Polytechnic
Nekede, both at Imo state. Imo state is outside the area of the study. The responses obtained were
analyzed using statistical package for the social sciences (SPSS) version 20. cronbach alpha
coefficient values of 0.91 was obtained for objectives, under content, 0.88 coefficient for cluster
B (Leak detection), 0.93 for cluster C (evacuation of contaminant), 0.86 for cluster D (trouble-
shooting electrical panel), 0.85 for cluster, E (recovery/recycling), 0.89 for cluster F (retrofitting
alternative refrigerant), 0.90 for cluster G (commissioning), 0.93 for cluster H (training
facilities), 0.92 for cluster I (teaching strategies), 0.89 for cluster J (evaluation techniques) the
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overall reliability of 178 items was 0.89 coefficient were obtained. The overall reliability of 178
items was 0.89 coefficient.
The inter-rater reliability was used to establish the reliability of( RAPRS) using three
raters. The raters were given rating guide to use for rating 10 technologists in a pilot testing class
on skills in leak detection, evacuation of contaminants, trouble-shooting electrical panel,
recovery/recycling, retrofitting, and commissioning in refrigeration and air-conditioning . The
inter-rater reliability was determined using Kendall’s coefficient of concordance 0.710,
indicating that there was internal consistency among the rater’s measurement of trainee’s
performance. (See Appendix IX, Pg. 226)
Step (IV) - Need Assessment
Method of Data Collection
Phase 1- Ninety-three copies of the questionnaire were administered on respondents in South-
South with the help of two Research Assistants (RAs). The Research Assistant were instructed
on proper administration, good handling and retrieval process of the questionnaire. The
researcher personally administered questionnaire to teachers of refrigeration and air-
conditioning. Copies of questionnaire were retrieved for analysis after two weeks. Out of the 93
copies administered, 87 copies were successfully retrieved.
Phase (11)-Administration of Refrigeration and Air-conditioning Psychomotive Rating
Scale (RAPRS), was used to obtain data on technologists performance before and after
interaction with the developed module.
Phase (11) Method of Data Analysis
1- Determination of goal for capacity building for refrigeration and air-conditioning
technologists was done through preliminary study. Data was analyzed using mean to answer
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research questions 1-5. Decision for the research questions were based on cut-off point of 2.5. In
other words, any item with mean 2.5 and above was considered as agreed and was accepted.
While any mean below 2.5. was taken as disagreed and was not be accepted (Ogbuanya &
Kpabep,2013).
2- (phase 1) -Need Assessment data was analyzed using mean to answer research questions 1 –
5. Decisions for the research questions were based on cut-off point of 3.0. In other words any
item with mean 3.0 was considered as Agreed and was accepted, while any mean below 3.0 was
taken as Disagreed and was not accepted. (See Appendix VIII, Pg. 217).
3- Data collected from try-out of developed module was analyzed using ANCOVA to test the
significance difference of the mean performance before and after training of the technologists at
0.05 significant level (See Appendix VII, Pg. 216).
Step- 5 Development of Module
Phase(1) The capacity building module was developed by the researcher after carrying need
assessment through the administration of questionnaires to experts in the field of refrigeration
and air-conditioning. The result obtained after data analysis was used to determine the
objectives, training facilities, teaching strategies, evaluation techniques and content. The module
had sub-headings that formed clusters of module standing on its own .The task in the clusters
was used to form specific objectives .Each specific objective was broken down into sequential
procedures/task, this agrees with Farooq (1997) who affirmed that selection and sequencing
modular topics of each module is made, stand out and dividing the content of total course into
sequence of topic or skill when developing module. Each section of module had accompanying
observable rating scale and training self-check list test. The sequential steps, self –check test,
module guide and introduction to module developed by the researcher, makes the developed
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module self–contained and self-sufficient instructional unit that will enable trainee to study on
their own pace (Silkwood, 2000).
Try-out was conducted after permission from the Head of Department of Mechanical
Engineering Department of Federal Polytechnic, Offa. The lecturer involved is a specialist in
refrigeration and air-conditioning, who has been involved in teaching and accrediting
refrigeration and air-conditioning courses in Polytechnics. Secondly the Polytechnic was
qualified to be used for try-out because refrigeration and air-conditioning courses are offered and
the necessary training facilities needed for try-out were available .The try-out was carried out
during normal school periods. The total number of 25 final year Higher National Diploma,
power/plant option were tried out on module utilization. The trainer was given one week to
understudy the module .The training was carried in three weeks. The rating scale was used to rate
before and after training without the trainee knowledge in order to assess the students exhibition
of natural behavior. A total of four weeks was planned to be used for the try-out. The rating scale
was based on the content, specific objectives and sequential step of each module. The scores of
students obtained from first and second rating were analyzed and used to test the hypothesis.
Based on hypothesis result obtained the final package was adopted (Appendix VII, Pg. 216).
114
CHAPTER FOUR
PRESENTATION AND ANALYSIS OF DATA
The collected data for the study were analyzed in order to provide answer to the research
questions and it is presented in this chapter. Discussion of the findings are also presented.
Research Question 1
What are the objectives of the capacity building modules for refrigeration and air-
conditioning technologists?
Data for answering the research question are presented in Table 1.
Table 1 Mean Response of Teachers, Technologists and Technicians on the objectives of capacity building modules for technologists in refrigeration and air-conditioning. N = 87 S/N Objectives of Capacity Building Module for Refrigeration
and Air Conditioning Technologists X SD Remark
1 Provide knowledge of effects of refrigerants on the environment. 4.91 .291 Agree 2 Provide skills that reduce emission of ozone depleting
refrigerants into the atmosphere 4.77 .423 Agree
3 Enhance the skill of technologists in trouble shooting electrical panels
4.79 .407 Agree
4 Enhance the skill of technologists in leak detection. 4.79 .407 Agree 5 Enhance the skill of technologists in evacuation of
contaminations 4.77 .450 Agree
6 Enhance the skill of technologist in recovering/ recycling 4.76 .430 Agree 7 Enhance the skill of technologists in retrofitting 4.74 .465 Agree 8 Enhance the skill of technologists in commissioning refrigeration
and air conditioning plants 4.78 .416 Agree
9 Develop safety and maintenance skill while installing, repairing and commissioning of refrigeration and air-conditioning plants
4.75 .437 Agree
10 Provide employability skill of technologists into refrigeration and air-conditioning service oriented industry.
4.75 .437 Agree
Key: X = Mean of Respondents, SD=Standard Deviation, N= Number of Respondents.
114
115
Data presented in Table 1 revealed 10 objectives of capacity building modules for refrigeration
and air-conditioning technologists. The mean for the objectives ranges 4.91 to 4.74. Each mean
is above the cut-off point of 3.0. Indicating that all the objectives are relevant to the development
of capacity building module for refrigeration and air-conditioning technologists. The standard
deviation values for the 10 general objectives ranges from .465 to .291 which indicated that the
respondent responses were not far from each other and the mean responses were close.
Research Question 2
What are the contents of the module for capacity building of refrigeration and air-
conditioning?
Data for answering research question 2 are presented under the following headings: Leak
Detection content, Evacuation of contaminant content, Trouble-shooting Electrical Panel content,
Recovery/Recycling content Retrofitting content and Content.
Data for answering research question 2 on content are presented in Table 2 -8.
Table 2 Mean Responses of Teachers, Technologists and Technicians on Leak Detection content N =87
S/N Leak Detection Content X SD Remark 1 Causes of leakage 4.79 .407 Agree 2 Types of leakage 4.82 .390 Agree 3 Mixing of soap solution 4.74 .465 Agree 4 Soap swap at piping’s joints 4.75 .437 Agree 5 Mirror view of swap joints 4.72 .450 Agree 6 Starting electronic leak detector 4.76 .430 Agree 7 Probing of joints with detector 4.76 .430 Agree 8 Symptoms of leak identification through light and sound 4.79 .407 Agree 9 Dye injection for leak detection 4.76 .430 Agree 10 Ultra violet light for leak detection 4.61 .491 Agree 11 Symptoms for leak through light glow 4.75 .437 Agree 12 Halide leak detector for detection . 4.71 .455 Agree 13 Lighting of halide torch 4.71 .455 Agree 14 Operate halide torch to identify leakage 4.71 .455 Agree 15 Symptoms of leakage with colour of flame 4.75 .437 Agree 16 Nitrogen charge for leak detection 4.74 .444 Agree Key: X =Mean of Respondents, SD = Standard Deviation N = Number of Respondents
116
The data presented Table 2 revealed 16 task of leak detection content for capacity
building module for technologists in refrigeration and air-conditioning. The mean for the content
ranges from 4.71 to 4.79. Each Mean is above the cut-off point of 3.5. This shows that all the
items on leak detection content were required for the development of capacity building module
for refrigeration and air-conditioning technologists. The standard deviation ranges from .407-
444 this revealed that the responses of the respondents were close.
117
Research Question 2
What are the contents of the modules for capacity building of refrigeration and air-
conditioning technologists?
Data for answering research question 2 on Evacuation of Contaminants content are
presented in Table 3.
Table 3 Mean Responses of Teachers, Technologists and Technicians on Evacuation of Contaminants content. N =87 S/N Evacuation Of Contaminants Content X S.D REMARK 1 Causes of contaminant in the system 4.77 .423 Agree 2 Reason for evacuation of contaminant 4.76 .430 Agree 3 Method of evacuation 4.76 .430 Agree 4 Equipment for evacuation 4.72 .450 Agree 5 Connection of manifold Gauge to vacuum pumps 4.68 .470 Agree 6 Connection of service hose to the system 4.71 .455 Agree
7 Run vacuum pump to satisfaction 4.71 .455 Agree 8 Reading of gauge for moisture pressure(100 microns or -
29.98mmhg) 4.67 .474 Agree
9 Pressurize the system with refrigerant 4.64 .482 Agree 10 Leak test system 4.79 .407 Agree 11 Use of heat to dissolve moisture from system 4.72 .450 Agree 12 Repair of leakage when found 4.75 .437 Agree 13 Repetition of vacuum process after leakage repair 4.85 .359 Agree 14 Performance test 4.75 .437 Agree Key: X = Mean of Respondents, SD = Standard Deviation , N = Number of Respondents The data presented in Table 3 showed the 14 items on content of evacuation of
contaminant for developing capacity building module for refrigeration and air–conditioning
technologists. The mean evacuation of contaminant ranges from 4.64 to 4.85. All the mean is
above the cut-off point of 3.0. This indicated that all the items on the content is relevant to the
development of capacity building module for refrigeration and air-conditioning technologists.
The standard deviation ranges between .359 and .482 which indicated that the opinion of the
respondents were close.
118
Research Question 2
What are the contents of the modules for capacity building of refrigeration and air-
conditioning technologists?
Data for answering research question 2 on Trouble-shooting Electrical Panel content are
presented in Table 4.
Table 4 Mean Responses of Teachers, Technologists and Technicians on Trouble-shooting Electrical Panel content N =87 S/N Trouble-Shooting Electrical Panel Content X S.D Remark 15 Identification of needed tools 4.75 .437 Agree
16 Isolate the panel from power source 4.78 .416 Agree
17 Removal of electrical panel cover 4.82 .390 Agree
18 Reading of wiring diagram on panel 4.74 .444 Agree
19 Colour code/number of cable for identification 4.80 .399 Agree
20 Use of Amp probe and Multimeter for continuity check on; 4.74 .444 Agree
21 Capacitor winding, loose contact, burnt contactor 4.55 .500 Agree
22 Relay winding and replacement of over load and replacement 4.78 .416 Agree
23 High and low pressure control windings 4.77 .423 Agree
24 Blown Fuse 4.76 .430 Agree
25 Motor winding (compressor) 4.70 .460 Agree
26 Replacement of burnt-out compressor 4.79 .407 Agree
Key X: Mean of Respondents, SD Standard Deviation, N=Numbers of Respondents. The data presented on table 4 revealed the 12 items on the content of trouble-shooting
electrical panel of the development of capacity building module for refrigeration and air-
conditioning technologists. The mean value for trouble-shooting electrical panel ranges from
4.55 to 4.82 The mean of all the items are above 3.0 the cut-off point ,this indicated that all the
items on the content is relevant to the development of capacity building module for refrigeration
and air-air-conditioning technologists. The standard deviation ranged from .437 to .407. This
indicated that the opinion of the respondents were not for apart.
119
Research Question 2
What are the contents of the modules for capacity building of refrigeration and air-
conditioning technologists?
Data for answering research question 2 on Recovery/Recycling content are presented in Table 5.
Table 5 Mean Responses of Teachers, Technologists and Technicians on Recovery/Recycling content N =87 S/N Recovery/Recycling Content X SD Remark 27 Concept of recovering/ recycling 4.72 450 Agree
28 Precaution to be taken when recovering 4.83 380 Agree
29 Identification of system refrigerant 4.80 399 Agree
30 Identification methods recovering 4.78 416 Agree
31 Identification of equipment required for recovering 4.72 450 Agree
32 Connection of recovering/recycling machine to system and recovery bottle
4.72 450 Agree
33 Connection of weighing scale to cylinder 4.66 478 Agree
34 Connection of piercing valve to domestic unit 4.72 450 Agree
35 Operation of recovering/recycling machine 4.71 455 Agree
36 Recording weight of recovered refrigerant 4.74 444 Agree
37 Recording of system pressure 4.77 423 Agree
38 Storage of recovered refrigerant in appropriate cylinder 4.77 423 Agree
Key: X=mean of the respondent, SD= standard deviation, N=Numbers of Respondents. The date presented in Table 5 showed the 13 items on recovery/recycling content for
developing capacity building module for refrigeration and air-conditioning technologists. The
mean for recovery recycling ranged from 4.71 to 4.83. The mean is above the cut-off point of
3.0. This indicated that all the items are relevant to the development of capacity building module
for refrigeration and air-conditioning technologists. The standard deviation ranged from .380 to
.478 which indicated that the respondents opinion were close and was not far from each other.
120
Research Question 2
What are the contents of the modules for capacity building of refrigeration and air-
conditioning technologists?
Data for answering research question 2 on Retrofitting content are presented in Table 6.
Table 6 Mean Responses of Teachers, Technologists and Technicians on Retrofitting content N =87 S/N Retrofitting Content X SD Remark
39 Re-appraisal of factors to be considered before retrofitting 4.79 .407 Agree
40 Re-appraisal of preliminary work to be done on unit before retrofitting
4.83 .380 Agree
41 Recovery of existing CFC/HCFC refrigerants 4.82 .390 Agree
42 Drain existing mineral oil in the crankcase 4.78 .416 Agree
43 Drier change 4.86 .347 Agree
44 Thermostat change (where applicable, industrial) 4.69 .465 Agree
45 Connection of weighing scale to cylinder 4.68 .470 Agree
46 Evacuation of system 4.76 .430 Agree
47 Replacement of mineral oil with polyester oil 4.75 .437 Agree
48 Change system with HFC refrigerant 4.76 .430 Agree
49 Monitor evaporator superheat with system on evacuation 4.72 .450 Agree
50 Charge alternative refrigerants 4.71 .455 Agree
51 Leak check 4.77 .423 Agree
52 Test run 4.76 .430 Agree
53 Prepare and fix retrofit label 4.76 .430 Agree
Key: Mean of Respondents, SD= Standard deviation N=Number of Respondents. The data presented in Table 6 revealed 15 items on retrofitting content for development
of capacity building module for refrigeration and air-conditioning technologists. The mean
ranged from 4.68 to 4.83. All the mean is above 3.0 the cut-off point. This revealed that all the
items are useful for the development of capacity building module for refrigeration and air-
conditioning technologists. The standard deviation ranged from .347 to. 470 showing that the
respondents’ opinion were not far from each other.
121
Research Question 2
What are the contents of the modules for capacity building of refrigeration and air-
conditioning technologists?
Data for answering research question 2 on commissioning content are presented in Table 7.
Table 7 Mean Responses of Teachers, Technologists and Technicians on Trouble-shooting Electrical Panel content, N =87
S/N Commissioning Content X SD Remark Visual check on: 54 Pipe work tightness and security 4.78 .416 Agree 55 Appropriate valve fitting 4.77 .423 Agree
56 Safety device and calibration 4.74 .444 Agree
57 Sight glass, drier standard exchange 4.86 .347 Agree
58 Pressure gauge fitting 4.78 .416 Agree
59 Provision of liquid receiver 4.76 .430 Agree
60 Provision of water system 4.77 .423 Agree
61 Components and bolt security 4.76 .430 Agree
62 Compressor mounting and oil level 4.75 .437 Agree
63 Pulley and coupling alignment 4.79 .407 Agree
64 Belt tension 4.80 .401 Agree
65 Motor and control circuit 4.71 .455 Agree
66 Enshrouded live components within panel 4.82 .390 Agree
67 Panel and switchgear cleanness 4.68 .470 Agree
68 Dryness and cleanliness of motor surrounding 4.76 .430 Agree
69 Correctness on internal links on starter 4.75 .437 Agree
70 Connection of all power control wiring 4.79 .407 Agree
71 Fuse/circuit breaker rating correctness 4.77 .423 Agree
72 Correctness of declared voltage rating in all supply phase 4.79 .407 Agree
73 Pressure test on installed system: 4.79 .409 Agree
74 Apply pressure to the compressor for oil test leakage 4.77 .423 Agree
75 Repair leaks if found 4.77 .423 Agree
76 Release pressure from system recovery 4.78 .416 Agree
77 Evacuation 4.75 .437 Agree
78 Charge refrigerant 4.72 .450 Agree
79 Leak test 4.75 .437 Agree
80 Efficiency test run 4.90 .306 Agree
Key: X= Mean of Respondent, SD= Standard Deviation, N= Number of Respondents.
122
The data presented in Table 7 revealed the 28 items on commissioning content for
developing capacity building module for refrigeration and air-conditioning technologists. The
mean for commissioning ranged from 4.71 to 4.90. The mean is above the cut-off point of 3.0.
This indicated that all the items are relevant for the development of capacity building modules.
The standard deviation ranged from .306 to .470. This indicated that the opinion of the
respondents were not far apart.
123
Research Question 3
What are the facilities required for the capacity building of refrigeration and air-
conditioning?
Data for answering research question 3 on facilities are presented in Table 8.
Table 8 Mean Responses of Teachers, Technologists and Technicians on Facilities. N =87 S/N Training Facility X SD Remark 1 Instructional guide 4.93 .255 Agree 2 Soap 4.68 .470 Agree 3 Clean water 4.75 .437 Agree 4 Container 4.70 .460 Agree 5 Mirror 4.60 .493 Agree 6 Electronic leak detector 4.80 .399 Agree 7 Ultra violet lamp 4.52 .503 Agree 8 Dye 4.32 .470 Agree 9 Halide torch 4.85 .359 Agree 10 Workman glove 4.63 .485 Agree 11 Refrigerators 4.56 .499 Agree 12 Air-conditioners 4.85 .359 Agree 13 Nitrogen set 4.77 .423 Agree 14 Manifold gauge 4.90 .306 Agree 15 Vacuum pump 4.71 .455 Agree 16 Service hose 4.86 .347 Agree 17 Flaring tool 4.62 .488 Agree 18 Swaging tool 4.75 .437 Agree 19 Protective clothing 4.69 .465 Agree 20 Piercing valve 4.62 .488 Agree 21 Amprobe meter 4.55 .500 Agree 22 Avometer 4.64 .482 Agree 23 Screw driver sets 4.61 .491 Agree 24 Workman Thermometer 4.55 .500 Agree 25 Pliers combination insulated sets 4.56 .499 Agree 26 Split air conditioner 4.64 .482 Agree 27 Scaffold 4.53 .502 Agree 28 Fire extinguisher 4.66 .478 Agree 29 Recovery/Recycling machine 4.39 .491 Agree 30 Electronic refrigerant weighing scale 4.78 .416 Agree 31 Recovery cylinder 4.76 .430 Agree 32 Service hose 4.91 .291 Agree 33 Oxygen/Acetylene Brazing set 4.66 .478 Agree 34 Oil Can 4.89 .321 Agree 35 Synthetic Esther oil 4.68 .470 Agree 36 Refrigerant identifier 4.83 .380 Agree 37 Installed central air-conditioner 4.75 .437 Agree 38 Spanner sets 4.78 .416 Agree 39 Copper bending sets 4.71 .455 Agree 40 Refrigerants(ozone friendly) 4.64 .482 Agree 41 Baizing rods 4.62 .488 Agree Key: X= Mean of Respondents, SD= Standard deviation. N= Number of Respondents
124
The data presented in Table 8 revealed 41 training facilities that are required for
development of capacity building module for refrigeration and air-conditioning technologists.
The mean for the training facilities ranges from 4.32 to 4.90. All the mean are above 3.0. The
cut-off point, hence all the items relevant to the development of the module. The standard
deviation ranged from .255 to 502 which indicated that the opinion of the respondents were not
too far apart but not too close.
125
Research Question 4
What are the teaching strategies that could be employed for implementing capacity
building module?
Data for answering research question 3 on facilities are presented in Table 9.
Table 9 Mean Responses of Teachers on teaching strategies. N =87.
S/N Teaching strategies X SD Remark 1. Demonstrate skills through depicting procedural task outlined in the particular module on
the expected skills then allow trainee to practice 5.00 .000 Agree
2. Create experimental conditions relating to the expected skills and allow trainee to analyze the result and relate it to real situation
4.83 .389 Agree
3. Use guided discussion with active participation of trainee to narrate specific skill on the module to allow trainee to practice
4.67 .492 Agree
4. Create small groups, give project on problems relating to stated skills on module and supervise trainee on steps to achieve result
4.50 .522 Agree
5. Describe the procedures on each expected skill on module, allow individual trainee to carry out the procedures and observe for correction
4.83 .389 Agree
6. Take trainee to industries practicing refrigeration and air-conditioning, instruct trainee to participate by asking questions and taking notes
4.58 .515 Agree
7. Give trainee expected task with check-lists and drill until expected skills are attained 4.75 .452 Agree 8. Create problem that will require trainee to carry out evacuation, recovery, retrofitting,
trouble-shooting electrical panel, observe training steps, check and correct procedures. 4.58 .515 Agree
9. Allow individual to carry out task, guided by module, check-list and self assessment that will direct trainee to escape module or repeat
4.67 .492 Agree
10. Use programmed instruction with the aid of the module, trainee is assessed after each step. 4.67 .492 Agree 11. Trainer gives assignment to trainee, assessed and corrected 4.67 .492 Agree 12. Trainer makes use of video, television, power point to train on refrigeration and air-
conditioning technology 5.00 .000 Agree
13. Trainer encourages training on workshop practical by giving them enough time to diagnose problems and rectifier
4.67 .492 Agree
14. Give opportunity to trainee to ask problem questions that will lead to practical solution 4.67 .492 Agree 15. Identify individual problems and group them accordingly for mastery 4.67 .492 Agree 16. Display facilities on each skills and make trainee identify and explain its use before
training 4.83 .389 Agree
17. Carry-out pre-test to ascertain trainee level before commencing training 4.92 .289 Agree 18. Use guided discussion to encourage participants on concepts of safety 4.67 .492 Agree 19. Use instructional guide. on module to emphasize effects of ozone depleting refrigerants on
the environment. 4.83 .389 Agree
20. Simulate learning through replication or mimic a real event or model a real situation 4.58 .515 Agree 21. Brainstorming using small group for generation of vast ideas for effective problem-
solving 4.67 .492 Agree
22. Case study, present a realistic situation that requires trainee to respond and explore possible solutions
4.50 .522 Agree
Key: Mean of Respondents, SD=standard deviation, N=Number of Respondents.
126
The data presented in Table 9 revealed 22 teaching strategies required for development of
capacity building modules for refrigeration and air-conditioning technologists. The mean for the
teaching strategies ranges from 4.50 to 5.00. The mean values are above 3.0. The cut-off point.
Hence, all the items are relevant to the development of capacity building modules. The standard
deviation ranged from .000 to .289. Showing that the opinion of the respondents were not far
apart.
127
Research Question 5
What are the Evaluation Techniques and activities that could be employed for the
implementing capacity building module?
Data for answering research question 5 on Evaluation techniques are presented in Table 10.
Table 10 Mean Responses of Teachers on Evaluation Techniques. N =87. S/N Evaluation Techniques X SD Remark 1 Prepare and conduct pre-test on each objective using objective
questions to determine trainee level before training 4.92 .289 Agree
2 Use check-list to evaluate performance with observation 4.83 .389 Agree
3 Set criteria for acceptance of mastering level, for example 80% 4.83 .389 Agree
4 Use self-check list for personal evaluation to encourage individualize learning as attached
4.83 .389 Agree
5 Use matching item that will indicate correct procedures of task 4.42 .515 Agree
6 Prepare specification of mastery skills and allow trainee to know expectation
4.67 .492 Agree
7 Allow trainee to repeat practicing until 80% of mastery skill is attained
4.83 .389 Agree
8 Criteria of mastery skills should be based on of the following specifications as attached on the next page
4.75 .452 Agree
9 Use rating scale to rate performance 4.50 .522 Agree
10 Use of easy questions to assess participants on cognitive domain 4.58 .515 Agree
11 Use of percentage for level of grading for certification 4.50 .522 Agree
Key: X= Mean of Respondents SD=standard deviation, N= Number of Respondents. The data presented on table 10 revealed 11 evaluation techniques required for
development of capacity building modules for refrigeration and air-conditioning technologists.
The mean for the evaluation techniques ranged from 4.42 to 4.83 above 3.5 the cut-off point.
That indicated that all the evaluation techniques are relevant to the development of capacity
building modules for refrigeration and air-conditioning technologists. The standard deviation
ranged from .289 to .522 showing that the respondents’ opinion were far apart.
128
Hypothesis Testing
There is no significant difference in the mean performance of technologists before and
after training with the developed module.
Table 11
Summary of Analysis of covariance (ANCOVA) for test of significance on mean
performance of technologists before and after training with the developed module.
Source Sum of Squares Df Mean Square F Sig Corrected model .028a 1 .028 1.208 .023 Intercept 30.499 1 30.499 1315.720 .000 Initial rating .028 1 .028 1.208 .023 Error .533 23 .023 Total 375.185 25 Corrected Total .561 24
R square = .050
Table 11 shows that the mean of technologists after training with the developed capacity
building module on refrigeration and air-conditioning was significant at .023 level of significant.
Hence the hypothesis which stated that there is no significant difference in the mean performance
of technologists before and after training with the developed module is rejected. The R square =
.050 shows that there is significant difference in the mean performance of technologists after
training with developed module.
129
Major Findings of the Study
The following findings emerged from the study based on the answered research
questions. The research questions were presented under the following sub-headings.
A. Objectives of Capacity Building Module for Refrigeration and Air Conditioning Technologists
1. Provide knowledge of effects of refrigerants on the environment.
2. Provide skills that reduce emission of ozone depleting refrigerants into the atmosphere
3. Enhance the skill of technologists in trouble shooting electrical panels
4. Enhance the skill of technologists in leak detection.
5. Enhance the skill of technologists in evacuation of contaminations
6. Enhance the skill of technologist in recovering/ recycling
7. Enhance the skill of technologists in retrofitting
8. Enhance the skill of technologists in commissioning refrigeration and air conditioning
plants
9. Develop safety and maintenance skill while installing, repairing and commissioning of
refrigeration and air-conditioning plants
10. Provide employability skill of technologists into refrigeration and air-conditioning service
oriented industry.
B. Content of Leak Detection
1. Causes of leakage
2. Types of leakage
3. Mixing of soap solution
4. Soap swap at piping’s joints
5. Mirror view of swap joints
130
6. Starting electronic leak detector
7. Probing of joints with detector
8. Symptoms of leak identification through light and sound
9. Dye injection for leak detection
10. Ultra violet light for leak detection
11. Symptoms for leak through light glow
12. Halide leak detector for detection
13. Lighting of halide torch
14. Operate halide torch to identify leakage
15. Symptoms of leakage with colour of flame
16. Nitrogen charge for leak detection
C. Content of Evacuation of Contaminant
1. Causes of contaminant in the system
2. Reason for evacuation of contaminant
3. Method of evacuation
4. Equipment for evacuation
5. Connection of manifold Gauge to vacuum pumps
6. Connection of service hose to the system
7. Run vacuum pump to satisfaction
8. Reading of gauge for moisture pressure(400 microns or -29.98mmhg)
9. Pressurize the system with refrigerant
10. Leak test system
131
D. Content of Trouble-Shooting Electrical Panel
1. Isolate panel from power
2. Remove electrical panel cover
3. Read wiring diagram on panel
4. Identify colour code/number of cables
5. Use Amp probe and Multimeter to check continuity on:
6. Capacitor winding, loose contact, burnt contactor
7. Relay winding,
8. High and low pressure control windings
9. Blown Fuse
10. Motor winding (compressor)
11. Replace bulk overload
12. Replace high and low pressure control
13. Replace blown fuse
14. Replace burnt compressor
E. Content of Recovery/Recycling
1. Concept of recovering/ recycling
2. Precaution to be taken when recovering
3. Identification of system refrigerant
4. Identification methods recovering
5. Identification of equipment required for recovering
6. Connection of recovering/recycling machine to system and recovery bottle
132
7. Connection of weighing scale to cylinder
8. Connection of piercing valve to domestic unit
9. Operation of recovering/recycling machine
10. Recording weight of recovered refrigerant
11. Recording of system pressure
12. Storage of recovered refrigerant in appropriate cylinder
F. Content of Retrofitting
55 Re-appraisal of factors to be considered before retrofitting
56 Re-appraisal of preliminary work to be done on unit before retrofitting
57 Recovery of existing CFC/HCFC refrigerants
58 Drain existing mineral oil in the crankcase
59 Drier change
60 Thermostat change (where applicable, industrial)
61 Connection of weighing scale to cylinder
62 Evacuation of system
63 Replacement of mineral oil with polyester oil
64 Change system with HFC refrigerant
64 Monitor evaporator superheat with system on evacuation
66 Charge alternative refrigerants
67 Leak check
68 Test run
69 Prepare and fix retrofit label
133
G. Content of Commissioning
Visual check on:
1. Pipe work tightness and security
2. Appropriate valve fitting
3. Safety device and calibration
4. Sight glass, drier standard exchange
5. Pressure gauge fitting
6. Provision of liquid receiver
7. Provision of water system
8. Components and bolt security
9. Compressor mounting and oil level
10. Pulley and coupling alignment
11. Belt tension
12. Motor and control circuit
13. Enshrouded live components within panel
14. Panel and switchgear cleanness
15. Dryness and cleanliness of motor surrounding
16. Correctness on internal links on starter
17. Connection of all power control wiring
18. Fuse/circuit breaker rating correctness
19. Correctness of declared voltage rating in all supply phase
20. Pressure test on installed system:
21. Apply pressure to the compressor for oil test leakage
134
22. Repair leaks if found
23. Release pressure from system recovery
24. Evacuation
25. Charge refrigerant
26. Leak test
27. Efficiency test run
H. Training Facilities
1. Instructional guide
2. Soap
3. Clean water
4. Container
5. Mirror
6. Electronic leak detector
7. Ultra violet lamp
8. Dye
9. Halide torch
10. Workman glove
11. Refrigerators
12. Air-conditioners
13. Nitrogen set
14. Manifold gauge
15. Vacuum pump
16. Service hose
135
17. Flaring tool
18. Swaging tool
19. Protective clothing
20. Piercing valve
21. Amprobe meter
22. Avometer
23. Screw driver sets
24. Workman Thermometer
25. Pliers combination insulated sets
26. Split air conditioner
27. Scatfold
28. Fire extinguisher
29. Recovery/Recycling machine
30. Electronic refrigerant weighing scale
31. Recovery cylinder
32. Service hose
33. Oxygen/Acetylene Brazing set
34. Oil Can
35. Synthetic Esther oil
36. Refrigerant identifier
37. Installed central air-conditioner
38. Spanner sets
39. Copper bending sets
136
40. Refrigerants (ozone friendly)
41. Braizing rods
I. Teaching Strategies
1. Demonstrate skills through depicting procedural task outlined in the particular module on
the expected skills then allow trainee to practice.
2. Create experimental conditions relating to the expected skills and allow trainee to analyze
the result and relate it to real situation.
3. Use guided discussion with active participation of trainee to narrate specific skill on the
module to allow trainee to practice.
4. Create small groups, give project on problems relating to stated skills on module and
supervise trainee on steps to achieve result.
5. Describe the procedures on each expected skill on module, allow individual trainee to
carry out the procedures and observe for correction.
6. Take trainee to industries practicing refrigeration and air-conditioning, instruct trainee to
participate by asking questions and taking notes.
7. Give trainee expected task with check-lists and drill until expected skills are attained.
Create problem that will require trainee to carry out evacuation, recovery, retrofitting,
trouble-shooting electrical panel, observe training steps, check and correct procedures.
Allow individual to carry out task, guided by module, check-list and self-assessment that
will direct trainee to escape module or repeat.
8. Use programmed instruction with the aid of the module, trainee is assessed after each
step
9. Trainer gives assignment to trainee, assessed and corrected.
137
10. Trainer makes use of video, television, power point to train on refrigeration and air-
conditioning technology
11. Trainer encourages training on workshop practical by giving them enough time to
diagnose problems and rectifier
12. Give opportunity to trainee to ask problem questions that will lead to practical solution
13. Identify individual problems and group them accordingly for mastery
14. Display facilities on each skills and make trainee identify and explain its use before
training
15. Carry-out pre-test to ascertain trainee level before commencing training
16. Use guided discussion to encourage participants on concepts of safety
17. Use instructional guide on module to emphasize effects of ozone depleting refrigerants on
the environment.
18. Simulate learning through replication or mimic a real event or model a real situation
19. Brainstorming using small group for generation of vast ideas for effective problem-
solving
20. Case study, present a realistic situation that requires trainee to respond and explore
possible solutions
J. Evaluation Techniques
1. Prepare and conduct pre-test on each objective using objective questions to determine
trainee level before training
2. Use check-list to evaluate performance with observation
3. Set criteria for acceptance of mastering level, for example 80%.
1. Use self-check list for personal evaluation to encourage individualize learning as
attached
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2. Use matching item that will indicate correct procedures of task
6. Prepare specification of mastery skills and allow trainee to know expectation
7. Allow trainee to repeat practicing until 80% of mastery skill is attained
8. Criteria of mastery skills should be based on of the following specifications as attached
on the next page
9. Use rating scale to rate performance
10. Use of easy questions to assess participants on cognitive domain
11. Use of percentage for level of grading for certification
K. There was significance difference in the mean performance of technologists before and after
training with the developed module.
Discussion of Findings
The major findings of the study are discussed as follows;
Objectives of Capacity Building Modules for Technologist in Refrigeration and Air-
conditioning
The findings revealed that the 10 objectives of capacity building modules for technologist
in refrigeration and air-conditioning includes; provides knowledge skills that reduce emission of
ozone depleting refrigerants into the atmosphere, enhance the skill of technologist in trouble-
shooting electrical panels, enhance the skill of technologist in evacuation, enhance the skill of
technologist in recovery/recycling, enhance skill of technologist in retrofitting, enhance skill of
technologist in commissioning refrigeration and air-conditioning plants, develop safety and
maintenance skill while installing, repairing and commissioning refrigeration and air-
conditioning plants and provide employability skill of technologist in refrigeration and air-
conditioning service oriented industry.
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The findings on objectives is in agreement with Mercede (2009) who identified
objectives as component of module also Bloom cited in silk wood (2000) that confirmed that in
writing general objectives, each objective should be stated in terms that indicates an overall
terminal learning outcome of the student. Ketaki, Odesma and Srividya (2012) also affirmed that
objectives can have these characteristics, what the learner should be able to do, conditions under
which the learner should be able to do and how well must it be done.
Major Findings of Content of Capacity Building Modules for Technologist in Refrigeration
and Air-conditioning
The findings under content of modules were analyzed under the following headings: leak
detection, evacuation of contaminants, trouble-shooting electrical panel, recovery/recycling,
retrofitting and commissioning.
Content of Leak Detection
The findings under leak detection revealed that the 16 items on the content includes,
causes of leakage, mixing of soap solution, types of leakage, soap swap at piping’s joints, mirror
view of swap joints, starting electronic leak detection, probing of joints with defector, symptoms
of leak identification through light and sound, dye injection for leak detection, ultra-violet light
for leak detection, symptoms for leak through light glow, Halide leak detection, lighting halide
torch, operate halide torch to identify leakage, symptoms of leakage with colour of flame and
Nitrogen charge for leak defection.
The findings agree with VTECH (2010) that confirmed methods of leak testing to be
electronic detector, soap solution tracer gas leak testing. UNEP (2010) confirmed use of
electronic method, bubble method. British Refrigeration Association (2010) recommended
electronic leak detector, ultraviolet indicator fluid and use of soap solution.
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Content of Evacuation of Contaminants
Findings under evacuation of contaminants revealed that the 14 items in the content
includes; causes of contaminants in the system, reason for evacuation of contaminants, method
of evacuation, equipments for evacuation connection of manifold gauge to vacuum pumps,
connection of services hose to the system, run vacuum to satisfaction, ready of gauge for
moisture pressure (400 microns or -29.98 mmhg) pressurize the system with refrigerant, leak test
system, use of heat to dissolve moisture form system, repair of leakage when found, repetition of
vacuum process after leakage repair and performance test.
The findings on evacuation is in agreement with Ridwan (2010) that confirmed effective
way of eliminating contaminant from the system is through the use of high vacuum pump, the
process usually involve connecting the system to a vacuum pump and allowing the pump to run
continuously for some time, while a deep vacuum is drawn to remove the contaminant.
Environmental safe refrigerant service tip and techniques (2013) confirmed that vacuum is drawn
below 500 microns for proper evacuation and removal of contaminant from refrigerating plants.
Content of Trouble-Shooting
Findings under trouble-shooting electrical panel revealed that the 12 items in the content
includes; identification of needed tools, isolate the panel form power sources, removal of
electrical panel cover, reading of wiring diagram on panel, colour code/number of cables for
identification, use of Amp- probe and multi-meter for continuity checks on capacity winding and
replacement of high and low pressure control winding, blown fuse, motor windings (compressor)
and replacement of burnt out compressor.
The findings were in support with Andrew, Carl and Alfred (2000) that trouble-shooting
of refrigeration and air-conditioning includes electrical components Warren (2013) confirmed
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components to be trouble-shooting to electrical panel. NADCA (2006) supported that check
should be carried out on electrical components such as overload relay, grounded windings in the
compression and electrical terminals.
Content of Recovery/ Recycling
Findings on recovery/recycling revealed that the 12 items in the content includes; concept
of recovery/recycling precaution to be taken when recovery, identification of system refrigerant,
identification of method of recovery, identification of equipment required for recovery,
connection of recovery/recycling machine to system and recovery bottle, connection of weighing
scale to cylinder connection of perching valve to domestic unit, operation of
recovering/recycling machine, recording weight of recovered refrigerant, recording of system
pressure, and storage of recovered refrigerant in appropriate cylinder. The findings on
recovery/recycling supported the recommended procedures for recommended procedures for
recovery/recycling by Williams and Williams (1995), Rajput (2012), Arora (2012). UNEP
(1995) recommended that training on recovery/recycling be made compulsory for those who
install, repair refrigeration and air-conditioning plants containing ozone depleting refrigerants for
preservation of refrigerants and prevention of emission.
Content of Retrofitting
Findings under retrofitting content revealed that 15 items in the content includes re-
appraisal of factors to be considered before retrofitting, retrofitting, re-appraisal of preliminary
work to be done on unit before retrofitting, recovery of existing CFC/HCFC refrigerants, drain
existing mineral oil in the crankcase, drier change, thermostat change (where applicable,
industrial), connection of weighing scale of cylinder, evacuation of system with HFC
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refrigerant, monitor evaporator superheat with system on evacuation, charge alternative
refrigerants leak checks, test run and prepare and fix retrofit label.
The findings were in agreement with ASHRAE (2010), recommended procedures for
retrofit. National Refrigerants (www.refrigerant.com) recommend that retrofitting procedure to
include preliminary check, record of recovered refrigerant, replacement of seals and gasket, leak
check and repair, filter drier, compressor oil and thermostatic expansion replacement. This view
is also supported by Honey Genetron (www.genetron.com).
Content of Commissioning
The findings on commissioning revealed 27 items in the commissioning content to
include carrying out visual check and correction on pipe work tightness and security, appropriate
valve fitting, safety device and calibration, sight glass, drier standard exchange, pressure gauge
fitting, provision of liquid receiver, provision of water system, components and bolt security,
compressor mounting and oil level pulley and coupling alignment, belt tension, motor and
control circuit, enshrouded live components within panel, panel and switch gear cleanness,
dryness and cleanliness of motor surrounding, correctness on interval links on starter, connection
of all power control wiring, fuse/circuit breaker rating correctness, correctness of declared
voltage rating in all supply phase, pressure text on installed system apply pressure to the
compressor for oil test leakage, repair leak if found and release pressure from system recovery.
The findings of the study were in agreement with Paul (2005) that confirmed that
comprehensive commissioning program identifies and correct costly performance deficiencies.
Architectural services department (2001) confirmed that visual check and correction with record
performance data of the whole installation as the base line for official operation and maintenance
is important and compulsory for safe condition before start-up.
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Training Facilities
The findings on training facilities revealed that 41 training facilities to include
instructional guide, soap, clean water, container, mirror, electronic leak detector, ultra violet
lamp, dye, halide tourch, workman glove, refrigerator, Air-conditioners, Nitrogen set, manifold
gauge, vacuum pump, service hose, flaring tool, savaging tool, protective clothing, piercing
valve, Amprobe-meter, Avometer, screw driver sets, split air-conditioner, scaffold, fire
extinguisher, recovery/recycling machine, electronic refrigerant weighing scale, recovery
cylinder, service hose oxygen/acetylene brazing set, oil can and synthetic esther oil. Refrigerant
identifier, installed central air-conditioner spanner sets, copper bending sets, Refrigerants (Ozone
friendly) and brazing rods.
The findings is in agreement with NBTE (2001) that stipulated specific equipment and
tools such as swaging tools, flaring tools, oxygen/acetylene brazing equipments among others for
teaching refrigeration and air-conditioning. ASHREA (2001), UNEP (2006) that confirmed
recovery machine, vacuum pump, electronic refrigerant weighing scale, recycling machine for
good practical in refrigeration and air-conditioning.
Teaching Strategies
The findings revealed 21 teaching strategies to include create experimental conditions
relating to the expected skills and allow trainee to analyze the result and relate it to real situation,
use guided discussion with active participation of trainee to narrate specific skill on the module
to allow trainee to practice, create small groups, give project on problems relating to slated skills
on module and supervise trainee on steps to achieve result, describe the procedures on each
expected skills on module, allow individual trainee to carry out the procedures and observe for
correction, take trainee to industries practicing refrigeration and air-conditioning, instruct trainee
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to participate by asking questions and taking notes, give trainee expected task with checklist and
drill until expected skills are attained, create problem that will require trainee to carryout
evacuation recovery, retrofitting, trouble-shooting electrical panel, observe trainee steps, check
and correct procedures allow individual to carryout task, guided by module check-list and self-
assessment that will direct trainee to escape module or repeat, use programmed instruction with
the aid of the module, trainee is assessed after each step, trainee gives assignment to trainee,
assed and corrected, trainer makes use of video, television, power point to train on refrigeration
and air-conditioning technology, trainer encourages training on workshop, practical by giving
them enough time to diagnose problems and rectifier, give opportunity to trainee to ask problem
questions that will lead to practical solution, identify individual problems and group them
accordingly for mastering, display facilities on each skills and make trainee identify and explain
its sure before training, carryout pre-test to ascertain trainee level before commencing training,
used guided discussion to encourage participation on concept of safety, use instructional guide
on module to emphasize effect of ozone depleting refrigerants on the environment, stimulate
learning through replication or mimic a real event or model a real situation, brainstorming using
small group for generation of vast ideas for effective problem-solving, case study, present a
realistic situation that requires trainee to respond and explore possible solutions.
The findings of the study is in agreement with Mangal and Margal (2012) that
ascertained that teaching strategies devised and employed by the teachers for guiding, directing
and showing path to the learner for the realization of the set instructional objectives. Mangal
further identified teaching strategies to include lecture strategies, demonstration strategies,
tutorial strategy, supervised study strategy, narration strategies, description strategy, exposition
strategy, explanation strategy, illustration strategy, programmed instruction strategy, role-play
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strategy, recapitulation strategy, group discussion strategy, question-answer strategy, discovery
or heuristic strategy, problem solving strategy, project strategy, independent study strategy,
dramatic strategy, assignment strategy, drill or practice work strategy, excursion strategy,
strategy of employment Audio Visual aid, brainstorming strategy and computer assisted
instructional strategy. The study of Alipour (2009) confirmed that teaching practical skills
involves practicing behavior in real or stimulated fashion.
Evaluation Techniques
The findings on evaluation techniques revealed 11 techniques that are required to be used
during utilization of capacity building module for technologist in refrigeration and air-
conditioning to include prepare and conduct pre-test on each objective using objective questions
to determine trainee level before training, used check-list to evaluate performance with
observation, set criteria for acceptant of mastering level, for example so go, use self-check list
for personal evaluation to encourage individuals learning as attached, use matching items that
will indicate correct procedures of task, prepare specification, of mastery skills and allow trainee
to know expectation, allow trainee to know repeat practicing until 80% of mastering skill is
attained, criteria of mastering skills should be based on the following specification of rating
scale, use rating scale to rate performance, use of essay question to asses participant on
congruities domain and use of percentage for level of grading for certification.
The findings supported Wendy (2002) who confirmed evaluation for competencies should be
based on goals of the training process. Dick and Carry (1979) and Kelly
(http://edutechwikk.Unge.Chlenlkemp-design-module) supports the view that in developing
instructional assessment, purpose of entering behavior practical item practical problem must be
stated and the performance objective should consist the condition or criteria of expected level of
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mastery. Mangal and Mangal (2012) and Osinem (2005) confirmed the use check-list, rating
scale, oral question, project and procedural testing evaluation techniques.
Try Out of Developed Module
Analysis of covariance was used to test the hypothesis which stated that there was no
significance difference in the mean performance of technologists before and after training with
the developed module. Inference shows that there was a significance difference at .023 level of
significant. There was significance in the mean performance of technologists before and after
training with developed module. The result showed that utilization of module affected the
improved performance of the technologists. The finding agrees with the findings of Onuka
(2008) that developed and validated trial-testing skills training modules for enhancing youths
participation in cassava processing. Onuka found out that those trained with the developed
modules performed to NAFDC regulating standard.
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CHAPTER FIVE
SUMMARY, CONCLUSION AND RECOMMENDATION
This chapter presents the summary of statement of the problem, procedures used and the
major findings. Also presented in this chapter includes conclusion based on the findings, the
implication of the findings, recommendations for implementation and suggestion for further
research.
Restatement of the Problem
One of the major causes of Ozone depletion is the emission of Ozone depleting
refrigerants into the atmosphere by the repairers of refrigerators and air- conditioners, especially
the technologists who work on big industrial plants containing large volume of refrigerants. The
emitted refrigerants contain Chlorine molecule which, when emitted, causes Ozone depletion.
Ozone depletion is the cause of global warming that is responsible for food scarcity, human
having short life span as a result of skin cancer, reduction of immune system, eye cataract and
disappearance of some animal species and ecosystem.
More so, majority of industrial air-conditioners, transportation and marine air-
conditioners/refrigerators, commercial refrigerators and air-conditioners, including the
refrigerators and air conditioners in some offices, homes, churches and restaurants all contain
Ozone depleting refrigerants. Therefore, Individuals and companies still having these systems
need to retain these equipment. Skills for leak detection, evacuation of contaminant trouble-
shooting electrical panel, recovery/recycling and commissioning are the vital skills that are
internationally recommended for technologists, to enable them repair, maintain and convert, if
possible, the ozone depleting refrigerant systems to ozone friendly systems without venting
ozone depleting refrigerants into the atmosphere.
147
148
Preliminary study carried out by the researcher revealed that technologists in the South-
South do not acquire these skills and the industries expect technologists to acquire these skills.
The possible reason why our technologists are not yet acquiring these skills is because these vital
skills are not included in the curriculum of the National Board for Technical Education that is
used for training the technologists in Polytechnics. The problem of this study therefore is that
there is no module in leak detection, evacuation of contaminants, trouble - shooting electrical
panel, recovering/recycling, retrofitting alternative refrigerants, and commissioning for the
capacity building of technologists in refrigeration and air- conditioning. Specifically, the study
will determine the following:
1. Objectives of the modules for the capacity building of refrigeration and air-condition
technologists.
2. Content of the modules for capacity building of refrigeration and air-condition technologists.
3. Teaching strategies for capacity building of refrigeration and air-condition technologists.
4. Training facilities for capacity building of refrigeration and air-condition technologists.
5. Evaluation techniques for capacity building of refrigeration and air-condition technologist.
6. Develop modules for capacity building of refrigeration and air-conditioning technologists.
7. Try out of developed module.
Summary of the Procedures Used for the Study
Research and development design (RSD) was used for the study. Population of the study
was 116 comprising 12 teachers of refrigeration and air-conditioning in south-south
polytechnics, technical college and craft center, 34 refrigeration and air-conditioning
technologist, 45 technicians and 25 final year students of Federal Polytechnic Offa five research
questions and one hypothesis were developed in agreement with the purpose of the study. One
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set of questionnaire having section A-E was developed to obtain information from respondents
based on the literature reviewed. Copies of the instrument were validated by two lecturers, one
from vocational teacher education, and mechanical engineering department, university of Nigeria
Nsukka and two experts of refrigeration and air-conditioning in the industries. Cronbach alpha
was used to determine the internal consistency of the instrument and reliability coefficient of
0.90 was obtained. The reliability of the (RAPRS) was determined by using inter-rater reliability
by pilot testing using three inter-raters. The result was calculated using Kendall’s coefficient of
concordance and 0.710 coefficient was obtained, indicating that there was internal consistency
among the rater’s measurement of trainee’s performance. Ninety-seven copies of questionnaire
for capacity building refrigeration and air-conditioning technologist, was administered on
refrigeration and air-conditioning technologist, technicians and teaching in south-south with the
help of five research assistants. Out of these, 87 copies were returned, adequately completed.
The data obtained was analyzed using mean and standard deviation to answer research question 1
to 5. The major finding were used to develop the refrigeration and air-conditioning capacity
building modules. The module draft was trial-tested on 25 final year, Higher National Diploma,
mechanical students of Federal Polytechnic, Offa in order to test the validity of modules in order
to for answering research question 6. The results obtained were used to package the final
module.
Major Findings of the Study
The following findings were made based on the data obtained and analyzed.
1. The 10 general objectives of refrigeration and air-conditioning capacity building modules
were found.
150
2. All the content of module on leak detection, evacuation of contaminants, trouble-shooting,
recovery/ recycling, retrofitting and coming were accepted by respondents.
3. The study found out that 41 training facilities were adequate for the module.
4. All the 22 teaching strategies were accepted for the module.
5. All the 11 evaluation techniques were found to be agreed upon.
6. Developed module was significant at .023.
Implication of the Study
The findings of the study have major implications to technologists, technicians,
craftsmen, artisans, skill training centers, technical skills instructional developers, instructors of
refrigeration and air-conditioning, National Board for Technical Education, National Association
of Refrigeration and Air-conditioning, examining bodies, Federal Ministry of Environment and
ozone program implementation and management unit.
Technologist, technician, craftsmen and artisan
When the capacity building modules developed by this study is made available to the
public, technologists, technicians, craftsmen and artisans that are already practicing but need to
improve their skills might register with any of the training centers having the modules for
upgrading of their skills for proper employable skills. Secondly, when those trained with the
module practice the newly acquired skills, reduction of emission of ozone depleting refrigerant
into the atmosphere will be realized.
Skills development centers
Skills development centers such as Polytechnics, technical colleges, industrial training
centers will use the modules for teaching practical in refrigeration and air-conditioning for high
practical skills competence when the module produced by the study is adopted.
151
National Board for Technical Education
National Board for Technical Education who is in charge of Polytechnics and technical
colleges might utilize the content of the module produce by the study for curriculum
modification.
Technical skills instructional developers
The methodology and content of modules produced by the study if made available, will
be a source of reference to technical skills instructional developers, when producing technical
training modules, both in refrigeration and other technical courses.
Instructors of refrigeration and air-conditioning
If the module produced by the study is made available to schools in south-south Nigeria,
the refrigeration and air-conditioning instructors who do not adequately acquire all the skills for
management of ozone depleting refrigerants will utilize the module for self-capacity building to
enable efficient training skills. And the youth trained will acquire the needed employable skills.
Ozone Programme Implementation and Management Unit in Collaboration with Federal
Ministry of Education
The Ozone programme implementation and Management unit in collaboration with
Federal Ministry of Education might utilize the modules produced by this study for capacity
building of teachers, practitioners of refrigeration and air-conditioning for management of Ozone
depletion.
National Association of Refrigeration and Air-conditioning Practitioners
The modules produced by this study might be utilize to train and test members already
registered and those to be registered as professional members who want to practice the
international standard of the professionalism.
152
Industries and the entire society
When those trained or re-trained with the modules produced by this study are employed
by the industries there will be less broken down of the systems and less emission of ozone
depleting refrigerants into the atmosphere, hence the environment will be protected and the entire
society will benefit from high productivity and safe environment.
Conclusion
Refrigeration and air-conditioning refrigerants that are in the categories of Hydro
chlorofluorocarbon and chlorofluorocarbon have been identified to be responsible for 50% ozone
depletion. These categories of refrigerants need to be managed through expert skills of
technologists, in order to reduce emission of ozone depleting refrigerant into the atmosphere.
Secondly the technology of retrofitting enables the conversion of systems with ozone depleting
refrigerants to ozone friendly refrigerant. The technology of recovery/ recycling brings about
economical management of both ozone depleting refrigerants and ozone friendly refrigerants.
Hence these skills that been developed into modules are capable to develop the capacity of
refrigeration and air-conditioning professionals. These new skills are internally needed for
employability and environmental protection. For these reasons the study was carried out.
To determine the gap for the study, preliminary study was carried out in order to find out
the needed skills in refrigeration and air-conditioning. Based on the findings, the researcher
carried out need assessment to determine the component and contents of the module. The result
obtained was used to develop capacity building module in refrigeration and air-conditioning for
technologists in South-South Nigeria. The developed module was tried out and the result reveals
that, the module was effective in improving the skill performance of technologists.
153
Utilization of the developed module in teaching, learning refrigeration and air-
conditioning in polytechnics will develop expertise skill that is internally needed from graduates
of polytechnics. Based on the findings from this study, it was recommended that practical
contents of all courses in polytechnics be taught with the aid of module.
Recommendation
Based on the findings of the study, the following recommendations are made:
1. National Board for Technical Education should set up curriculum review committee that will
use the module contents for modification of refrigeration and air-conditioning practical
content.
2. Federal Government should re-train polytechnic teachers and graduates of polytechnics for
capacity building in refrigeration and air-conditioning using the developed modules.
3. Federal Ministry of Environment and Ozone Programme Implementation and Management
Unit should create capacity building centres that will re-train refrigeration practitioners using
the developed module.
4. Technologists, technicians, artisans that install, repair and commission refrigeration and air-
conditioning need to develop their capacity in the new technology through retraining with the
developed module to enable them practice without emission of ozone depleting refrigerant
into the atmosphere.
5. Skill development centres and entrepreneurship centers for refrigeration and air-conditioning
should include the new skills in the curriculum, use of the developed module and acquisition
of needed equipment for effective transmission of skills.
6. Instructor of refrigeration and air-conditioning in polytechnics should be re-train on
development and utilization of module for effective delivery of all practical contents in
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refrigeration and air-conditioning at all levels for technological growth, employability and
environmental protection.
Suggestion for Further Studies
These suggestion were given for further studies
1. Development of modules should be carryout to cover all topics in refrigeration and air-
conditioning.
2. Visual and audio module development should be undertaken on refrigeration and air-
conditioning skills.
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166
Appendix I
Letter to Validate of Module
Department of Industrial Technical Education, University of Nigeria, Nsukka.
Dear Sir/Madam,
REQUEST FOR USE OF YOUR SCHOOL, DEPARTMENT AND STUDENTS
I am a Doctoral student of department of Industrial Technical Education, Mechanical
Technology option (Industrial Education), University of Nigeria, Nsukka.
My research involves development of Capacity building Modules for Technologists in
Refrigeration and Air-conditioning, South-South Nigeria. Your institution is nominated to join
in the validation of the developed modules, because of your professionalism and being one of the
retrained lecturers in good practices in refrigeration and air-conditioning in Nigeria. We are also
aware that your institution is well equipped for the training.
I hereby, request that you use the modules along with the attached psychomotive rating
scale, self-check lists and objective question to rain and evaluate your higher national Diploma
year II accordingly within two weeks and send the students’ performance back to me.
Thank you for your co-operation.
Yours faithfully,
Kpabep, Charity M. (Researcher)
167
Appendix II
Request for Respondent Participation
Department of Industrial Technical Education, University of Nigeria, Nsukka.
Dear Sir/Madam,
REQUEST FOR YOUR PARTICIPATION IN THE RESEARCH I am a Doctoral student in the department of Industrial Technical Education; Industrial
Education, University of Nigeria, Nsukka.
I am undertaking a research topic: Development of Capacity Building Modules for
Technologist in Refrigeration and Air-conditioning, South-South Nigeria. In recognition to your
professionalism in refrigeration and air-conditioning, I realize that your response to the
questionnaire will contribute to the development of valid modules.
I hereby, request you to respond to he attached questionnaire in order to elicit the
necessary information for the study. Kindly respond as objectively as possible and be assured
that the information will be treated with confidence.
Thank you for your co-operation.
Yours faithfully,
Kpabep, Charity M. (Researcher)
168
Appendix III
Questionnaire for the Development of Capacity Building Module for Refrigeration and Air Conditioning Technologists
This questionnaire is designed to elicit information that will lead to the development of capacity
building module for technologists who are graduates of polytechnics. You are please requested to
be as objective as possible.
SECTION A: Personal Data
Name of Establishment:
Instruction : Check (√) in the box as it applies to you.
Lecturer/Instructor/Teacher of Refrigeration and Air-Conditioning ( )
Refrigeration and Air-Conditioning Supervisor/Technologist/technician ( )
SECTION B: Objectives of Capacity Building Module for Refrigeration and Air-Conditioning
Technologists
Instruction : Please indicate your opinion on the extent to which the following items are suitable
as objectives by ticking (√) using the following response categorist (Strongly Agree “SA”, Agree
“A”, Undecided “U”, Disagree “D”, Strongly Disagree “SD”)
Objectives of Capacity Building Module for Refrigeration and Air Conditioning Technologists
SA A U D SD
1 Provide knowledge of effects of refrigerants on the environment. 2 Provide skills that reduce emission of ozone depleting refrigerants into the
atmosphere
3 Enhance the skill of technologists in trouble shooting electrical panels 4 Enhance the skill of technologists in leak detection. 5 Enhance the skill of technologists in evacuation of contaminations 6 Enhance the skill of technologist in recovering/ recycling 7 Enhance the skill of technologists in retrofitting 8 Enhance the skill of technologists in commissioning refrigeration and air
conditioning plants
9 Develop safety and maintenance skill while installing, repairing and commissioning of refrigeration and air-conditioning plants
10 Provide employability skill of technologists into refrigeration and air-conditioning service oriented industry.
Please kindly comment
169
SECTION C: Content of the Capacity Building Module on Refrigeration and Air- Conditioning SECTION C: (i) Leak Detection
Instruction: Please indicate your opinion on the following as regards the suitability of the
contents by ticking (√) using the following response categories (Strongly Agree “SA”, Agree
“A”, Undecided “U”, Disagree “D”, Strongly Disagree “SD”)
Leak Detection Content SA A U D SD
1 Causes of leakage
2 Types of leakage
3 Mixing of soap solution
4 Soap swap at piping’s joints
5 Mirror view of swap joints
6 Starting electronic leak detector
7 Probing of joints with detector
8 Symptoms of leak identification through light and sound
9 Dye injection for leak detection
10 Ultra violet light for leak detection
11 Symptoms for leak through light glow
12 Halide leak detector for detection
13 Lighting of halide torch
14 Operate halide torch to identify leakage
15 Symptoms of leakage with colour of flame
16 Nitrogen charge for leak detection
Please kindly comment
170
SECTION C (II): Content of Capacity Building Modul e for Evacuation of
Contaminants
Evacuation Of Contaminants Content SA A U D SD
17 Causes of contaminant in the system
18 Reason for evacuation of contaminant
19 Method of evacuation
20 Equipments for evacuation
21 Connection of manifold Gauge to vacuum pumps
22 Connection of service hose to the system
23 Run vacuum pump to satisfaction
24 Reading of gauge for moisture pressure(400microns or -
29.98mmhg)
25 Pressurize the system with refrigerant
26 Leak test system
27 Use of heat to dissolve moisture from system
28 Repair of leakage when found
29 Repetition of vacuum process after leakage repair
30 Performance test
Please kindly comment
171
SECTION C (III): Content of capacity building modul e for Trouble-Shooting Electrical
Panel
Instruction: Please indicate your opinion on the following items as regard the suitability of the contents by ticking (√) using the following response categories (Strongly Agree “SA”, Agree “A”, Undecided “U”, Disagree “D”, Strongly Disagree “SD”)
Trouble-Shooting Electrical Panel Content SA A U D SD
31 Identification of needed tools
32 Isolate the panel from power source
33 Removal of electrical panel cover
34 Reading of wiring diagram on panel
35 Colour code/number of cable for identification
36 Use of Amp probe and Multimeter for continuity check on;
37 Capacitor winding, loose contact, burnt contactor
38 Relay winding and replacement of over load and replacement
39 High and low pressure control windings
40 Blown Fuse
41 Motor winding (compressor)
42 Replacement of burnt-out compressor
Please kindly comment
172
SECTION C (IV) Content of capacity building module for Recovery/Recycling
Instruction : Place indicate your opinion on the following items as regards the suitability of the contents by ticking (√) using the following response categories (Strongly Agree “SA”, Agree “A”, Undecided “U”, Disagree “D”, Strongly Disagree “SD”)
Recovery/Recycling Content SA A U D SD
43 Concept of recovering/ recycling
44 Precaution to be taken when recovering
45 Identification of system refrigerant
46 Identification methods recovering
47 Identification of equipment required for recovering
48 Connection of recovering/recycling machine to system and recovery
bottle
49 Connection of weighing scale to cylinder
50 Connection of piercing valve to domestic unit
51 Operation of recovering/recycling machine
52 Recording weight of recovered refrigerant
53 Recording of system pressure
54 Storage of recovered refrigerant in appropriate cylinder
Please kindly comment
173
SECTION C (V): Content of capacity building module for Retrofitting
Instruction : Please indicate your opinion on the following items as regard the suitability of the contents by ticking (√) using the following response categories (Strongly Agree “SA”, Agree “A”, Undecided “U”, Disagree “D”, Strongly Disagree “SD”) Retrofitting Content SA A U D SD
55 Re-appraisal of factors to be considered before retrofitting
56 Re-appraisal of preliminary work to be done on unit before
retrofitting
57 Recovery of existing CFC/HCFC refrigerants
58 Drain existing mineral oil in the crankcase
59 Drier change
60 Thermostat change (where applicable, industrial)
61 Connection of weighing scale to cylinder
62 Evacuation of system
63 Replacement of mineral oil with polyester oil
64 Change system with HFC refrigerant
64 Monitor evaporator superheat with system on evacuation
66 Charge alternative refrigerants
67 Leak check
68 Test run
69 Prepare and fix retrofit label
Please kindly comment
174
SECTION C (V): Content of capacity building module for Commissioning
Instruction : Please indicate your opinion on the following items as regard the suitability of the contents by ticking (√) using the following response categories (Strongly Agree “SA”, Agree “A”, Undecided “U”, Disagree “D”, Strongly Disagree “SD”)
Commissioning Content SA A U D SD Visual check on: 70 Pipe work tightness and security 71 Appropriate valve fitting 72 Safety device and calibration 73 Sight glass, drier standard exchange 74 Pressure gauge fitting
75 Provision of liquid receiver 76 Provision of water system 77 Components and bolt security 78 Compressor mounting and oil level 79 Pulley and coupling alignment 80 Belt tension 81 Motor and control circuit 82 Enshrouded live components within panel 83 Panel and switchgear cleanness 84 Dryness and cleanliness of motor surrounding 85 Correctness on internal links on starter 86 Connection of all power control wiring 87 Fuse/circuit breaker rating correctness 88 Correctness of declared voltage rating in all supply phase 89 Pressure test on installed system: 90 Apply pressure to the compressor for oil test leakage 91 Repair leaks if found 92 Release pressure from system recovery 93 Evacuation 94 Charge refrigerant 95 Leak test 96 Efficiency test run
Please kindly comment
175
SECTION D: TRAINING FACILITIES
Section D: Training Facilities Instruction: please indicate your opinion as regards the suitability of the given training facilities
on the content by ticking () using the following response categories (Strongly Agree “SA”,
Agree “A”, Undecided “U”, Disagree “D”, Strongly Disagree “SD”)
Training Facility SA A U D SD 1. Instructional guide 2. Soap 3. Clean water 4. Container 5. Mirror 6. Electronic leak detector 7. Ultra violet lamp 8. Dye 9. Halide torch 10. Workman glove 11. Refrigerators 12. Air-conditioners 13. Nitrogen set 14. Manifold gauge 15. Vacuum pump 16. Service hose 17. Flaring tool 18. Swaging tool 19. Protective clothing 20. Piercing valve 21. Amprobe meter 22. Avometer 23. Screw driver sets 24. Workman Thermometer 25. Pliers combination insulated sets 26. Split air conditioner 27. Scatfold 28. Fire extinguisher 29. Recovery/Recycling machine 30. Electronic refrigerant weighing scale 31. Recovery cylinder 32. Service hose 33. Oxygen/Acetylene Brazing set 34. Oil Can 35. Synthetic Esther oil 36. Refrigerant identifier 37. Installed central air-conditioner 38. Spanner sets 39. Copper bending sets 40. Refrigerants(ozone friendly) 41. Braizing rods
Please comment
176
SECTION E: Teaching Strategies
Instruction: please indicate your opinion as regards the suitability of the given teaching
strategies on the content by ticking () using the following response categories (Strongly Agree
“SA”, Agree “A”, Undecided “U”, Disagree “D”, Strongly Disagree “SD”)
Teaching strategies SA A U D SD 1. Demonstrate skills through depicting procedural task outlined in the particular module on the
expected skills then allow trainee to practice
2. Create experimental conditions relating to the expected skills and allow trainee to analyze the result and relate it to real situation
3. Use guided discussion with active participation of trainee to narrate specific skill on the module to allow trainee to practice
4. Create small groups, give project on problems relating to stated skills on module and supervise trainee on steps to achieve result
5. Describe the procedures on each expected skill on module, allow individual trainee to carry out the procedures and observe for correction
6. Take trainee to industries practicing refrigeration and air-conditioning, instruct trainee to participate by asking questions and taking notes
7. Give trainee expected task with check-lists and drill until expected skills are attained 8. Create problem that will require trainee to carry out evacuation, recovery, retrofitting,
trouble-shooting electrical panel, observe training steps, check and correct procedures.
9. Allow individual to carry out task, guided by module, check-list and self assessment that will direct trainee to escape module or repeat
10. Use programmed instruction with the aid of the module, trainee is assessed after each step 11. Trainer gives assignment to trainee, assessed and corrected 12. Trainer makes use of video, television, power point to train on refrigeration and air-
conditioning technology
13. Trainer encourages training on workshop practical by giving them enough time to diagnose problems and rectifier
14. Give opportunity to trainee to ask problem questions that will lead to practical solution 15. Identify individual problems and group them accordingly for mastery 16. Display facilities on each skills and make trainee identify and explain its use before training 17. Carry-out pre-test to ascertain trainee level before commencing training 18. Use guided discussion to encourage participants on concepts of safety 20. Use instructional guide on module to emphasize effects of ozone depleting refrigerants on
the environment.
21. Simulate learning through replication or mimic a real event or model a real situation 22. Brainstorming using small group for generation of vast ideas for effective problem-solving 23. Case study, present a realistic situation that requires trainee to respond and explore possible
solutions
Please comment
177
SECTION F: Evaluation Techniques
Instruction: Please kindly indicate your degree of response as regards to the given evaluation
criteria appropriate for training of refrigeration and air-conditioning technologists by ticking ()
using the following response categories (Strongly Agree “SA”, Agree “A”, Undecided “U”,
Disagree “D”, Strongly Disagree “SD”)
Evaluation Techniques SA A U D SD 1. Prepare and conduct pre-test on each objective using
objective questions to determine trainee level before training
2. Use check-list to evaluate performance with observation 3.. Set criteria for acceptance of mastering level, for example
80%
4. Use self-check list for personal evaluation to encourage individualize learning as attached
5. Use matching item that will indicate correct procedures of task
6. Prepare specification of mastery skills and allow trainee to know expectation
7. Allow trainee to repeat practicing until 80% of mastery skill is attained
8. Criteria of mastery skills should be based on of the following specifications as attached on the next page
9. Use rating scale to rate performance 10. Use of easy questions to assess participants on cognitive
domain
11. Use of percentage for level of grading for certification
178
Appendix IV
CAPACITY BUILDING MODULE FOR REFRIGERATION AND AIR-CONDITIONING
TECHNOLOGISTS IN SOUTH-SOUTH NIGERIA
By
KPABEP, CHARITY MAELEERA
PG/Ph.D/08/49025
DEPARTMENT OF INDUSTRIAL TECHNICAL EDUCATION
UNIVERSITY OF NIGERIA, NSUKKA
EDITED BY: DR. T.C. OGBUANYA
179
Introduction to Module
Scientific research has proved that the chlorine content of common refrigerants used in
the Refrigerators and Air conditioners, when emitted into the atmosphere, strip an atom from the
Ozone molecule, yielding chloride oxide and normal oxygen. This process goes on to repeat
itself continuously and the replacement of chlorine molecule in oxygen is known as ozone
depletion. The depletion results to ultra-violet radiation of the sun on the Earth resulting to
Global warning of the Earth, thereby having destructive effect on Humans, Ecosystem, and plant
life.
Hence repairers of Refrigerators and Air conditioners such as technologists who carry out
leak detection, evacuation of contaminants from contaminated system, trouble-shoot electrical
panel, recover and recycle ozone depleting refrigerants, retrofit alternative refrigerants and
commission refrigeration and air-conditioning plants, containing these Refrigerants known as
chlorofluoro-carbon (CFC) and Hydrofluorochloro-carbon (HCFC) are expected to carry out
what is known as good practice. That is the ability to carry out the above mentioned tasks during
installation, repairs and commissioning in order to prevent venting of these Refrigerants into the
environment. Hence by the time the trainee go through the entire modules, the trainee will
acquire the needed skills. Acquisition of these vital skills will qualify the technologists as a good
Practitioner, needed for environmental protection and employability.
Instruction for Use of Module
These instruction serves as guidelines to the trainers and trainees who will utilize the
capacity building modules for enhancing the skills of technologists in refrigeration and air-
conditioning in leak detection, evacuation of contaminant ,trouble-shooting electrical panel,
recovery/recycling, retrofitting and commissioning refrigeration and air-conditioning plants
180
containing ozone depleting refrigerants. The modules are units of related skills required for
enhancing the skills of trainees.
Both trainers and trainees are expected to read the introduction to modules and modules
instructional guidelines carefully before commencing training.
General Objectives of Capacity Building Module for Refrigeration and Air-conditioning Technologists are to;
1. Provide knowledge of effects of refrigerants on the environment.
2. Provide skills that reduce emission of ozone depleting refrigerants into the atmosphere
3. Enhance the skill of technologists in trouble shooting electrical panels
4. Enhance the skill of technologists in leak detection.
5. Enhance the skill of technologists in evacuation of contaminations
6. Enhance the skill of technologist in recovering/ recycling
7. Enhance the skill of technologists in retrofitting
8. Enhance the skill of technologists in commissioning refrigeration and air conditioning
plants
9. Develop safety and maintenance skill while installing, repairing and commissioning of
refrigeration and air-conditioning plants
10. Provide employability skill of technologists into refrigeration and air-conditioning
service oriented industry.
The module have both general objectives and specific objective. The general objectives is
as stated above and the specific objectives are stated alongside the content at the
beginning of each module. This will guide the trainer and trainee to have a target at the
conclusion of each module.
181
Content of Module
The content of module is given in each module according to the expected skills, showing
the expected task broken down into small steps. The trainer is expected to follow the steps
sequentially.
Training Facilities
Training Facilities which could also be seen as instructional materials are the equipment,
instruments, and materials that are required for effective training in developing the skills of
technologists in refrigeration and air-conditioning. All the facilities will be displayed on each
module. Trainers are expected to select from the list, facilities that are appropriate for each
module.
Training Facility includes:
42. Instructional guide
43. Soap
44. Clean water
45. Container
46. Mirror
47. Electronic leak detector
48. Ultra violet lamp
49. Dye
50. Halide torch
51. Workman glove
52. Refrigerators
53. Air-conditioners
182
54. Nitrogen set
55. Manifold gauge
56. Vacuum pump
57. Service hose
58. Flaring tool
59. Swaging tool
60. Protective clothing
61. Piercing valve
62. Am probe meter
63. Avometer
64. Screw driver sets
65. Workman Thermometer
66. Pliers combination insulated sets
67. Split air conditioner
68. Scaffold
69. Fire extinguisher
70. Recovery/Recycling machine
71. Electronic refrigerant weighing scale
72. Recovery cylinder
73. Service hose
74. Oxygen/Acetylene Brazing set
75. Oil Can
76. Synthetic Esther oil
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77. Refrigerant identifier
78. Installed central air-conditioner
79. Spanner sets
80. Copper bending sets
81. Refrigerants(ozone friendly)
82. Brazing rods
Teaching Strategies
Teaching strategies are the various teaching techniques that could be employed by the
trainer for realization of the stated objectives. The trainer is expected to employ any among the
listed teaching strategies that is appropriate to expected task.
Teaching strategies includes:
1. Demonstrate skills through depicting procedural task outlined in the particular module on
the expected skills then allow trainee to practice.
2. Create experimental conditions relating to the expected skills and allow trainee to analyze
the result and relate it to real situation
3. Use guided discussion with active participation of trainee to narrate specific skill on the
module to allow trainee to practice.
4. Create small groups, give project on problems relating to stated skills on module and
supervise trainee on steps to achieve result.
5. Describe the procedures on each expected skill on module, allow individual trainee to
carry out the procedures and observe for correction.
6. Take trainee to industries practicing refrigeration and air-conditioning, instruct trainee to
participate by asking questions and taking notes.
184
7. Give trainee expected task with check-lists and drill until expected skills are attained.
8. Create problem that will require trainee to carry out evacuation, recovery, retrofitting,
trouble-shooting electrical panel, observe training steps, check and correct procedures.
9. Allow individual to carry out task, guided by module, check-list and self-assessment that
will direct trainee to escape module or repeat.
10. Use programmed instruction with the aid of the module, trainee is assessed after each
step.
11. Trainer gives assignment to trainee, assessed and corrected.
12. Trainer makes use of video, television, power point to train on refrigeration and air-
conditioning technology.
13. Trainer encourages training on workshop practical by giving them enough time to
diagnose problems and rectifier.
14. Give opportunity to trainee to ask problem questions that will lead to practical solution
15. Identify individual problems and group them accordingly for mastery.
16. Display facilities on each skills and make trainee identify and explain its use before
training.
17. Carry-out pre-test to ascertain trainee level before commencing training.
18. Use guided discussion to encourage participants on concepts of safety.
19. Use instructional guide on module to emphasize effects of ozone depleting refrigerants on
the environment.
20. Simulate learning through replication or mimic a real event or model a real situation.
21. Brainstorming using small group for generation of vast ideas for effective problem-
solving.
21. Case study, present a realistic situation that requires trainee to respond and explore
possible solutions.
185
MODULE A
NAME OF THE MODULE: Leak Detection
SPECIFIC OBJECTIVE: At the end of the training, trainee should be able to:
(1) Identify causes of leakage
(2) Identify types of leakage
(3) Select equipment for carrying out leak detection
(4) Carry out different methods of leak detection
Introduction:
Good maintenance of refrigeration and air-conditioning requires that minimization of emission
of refrigerants into the atmosphere is carried out through regular inspection of the pipings and
joints with the aid of leak detectors.
When a system is suspected to have leakage, the whole system should be checked. when the
leaking spot is found, the spot is marked for repair and recharged. It is not recommended by
good environmental practice to add refrigerant without first locating leaking spot and repairing
leakage.
Causes of Leakages:
(1) Vibration
(2) Accidental damage
(3) Poor quality material selection during installation
(4) Pressure change
(5) Temperature change
(6) Frictional wear
186
Selection of Equipment/Materials
(1) Soap
(2) Clean water
(3) Water container
(4) Mirror
(5) Electronic leak detector
(6) Ultra violet lamp
(7) Dye can
(8) Manifold gauge
(9) Refrigerator
(10) Air-Conditioner
(11) Halide torch
(12) Workman glove
(13) Nitrogen set
Practical Session
Leak detection method of leakage
Sequential steps/tasks
Step 1
1. Visually carryout check for oil residues round the system for sign of leakage.
2. Ensure that there is pressure in the system. The higher the pressure in the system, the
higher you obtain accurate result.
Step 2
1. Collect small quantity of soap either powered, tablet or liquid.
187
3. Pour small quantity of water into a container.
4. Mix soap solution
5. Swap soap solution at pipings joints with brush
6. Use mirror to view swap joints for symptom of leakage.
Observations:
Leaking refrigerants will form bubble .size of bubble formed will indicate level of leaks.
Fast or rapidly formed bubble indicates high leakage.
Step 3
Electronic leak detection method
Sequential steps/task
Start electronic leak detector by:
1. Turning on the start button.
2. Allow detector to warm for one minute away from the system
3. Probe joints with detector by slowly run sensing tip closely around suspected areas.
4. Identify symptom of leaks by adjusting sensitivity knob.
5. Symptom of leakage is given by increase tickling noise.
Step 4
Dye Injection leak detection method
Sequential steps/task
1. Connect dye can at the low side through manifold gauge.
2. Open dye can to release into the system and start system
3. Identify symptom of leakage by viewing dye color appearance at leaking spot after few
minutes of system operating.
188
Step 5
Halide Leak Detector Method
Sequential Steps/Task
Operation of Halide torch
1. Light torch and allow heat copper plate
2. Hold detector upright
3. Slowly pass the hose around all suspected areas
4. Identify symptom of leakage with small greenish trait flame indicate small leak.
5. A bright blue flame indicates large leak.
6. Close propane valve after check.
Step 6
Nitrogen Change Method
Sequential Steps/Task
1. Connect Nitrogen gauge
2. Connect Nitrogen to system through high pressure gauge
3. Gently open Nitrogen, allow (30 to 100 psi) pressure
4. Close valve and observe per one hour for pressure drop.
5. If no pressure drops, gently increase pressure to 170 psi.
Note: Do not release excess pressure to avoid explosion. It is used with only Halogenated
refrigerant.
189
MODULE B
NAME OF THE MODULE: Evacuation of Contaminants
SPECIFIC OBJECTIVE: At the end of the training, trainee should be able to:
1. Identify causes of contaminant
2. Identify reason for evacuation of contaminants
3. Select equipment for evacuation of contaminants
4. Identify method of evacuation
5. Carry out evacuation processes.
Introduction:
Evacuation of contaminants involves the use of vacuum pump that boils the existing
moisture in the system at room temperature to vapor. The vapor and air in the system is removed
by the vacuum pump. Basically the vacuum pump function to control the pressure in the system
under vacuum condition, the boiling point moisture (water) in the system is also lowered for easy
evaporation to occur. The vaporized moisture can then be easily drawn out by the vacuum
pump.
Causes of Contaminant
Anytime the system is opened to the atmosphere, the system is evacuated to ensure that
the system is free of air and moisture. Moisture and air mix with refrigerant raises the
compressor pressure, causing damage and it also reduces the performance of the system.
Reason for Evacuation
Evacuation is carried out when the following conditions arise;
1. Replacing compressor
2. Replacing condenser
3. Replacing evaporator
190
4. Replacing refrigerant control
5. After repairs of leakage
6. After change of system lubricating oil
Selection of Equipment
1. Manifold gauge
2. Vacuum pump
3. Service hose
4. Piercing valve
5. Refrigerator
6. Air-Conditioner
7. Workman Thermometer
Identification of Vacuum Method
1. Deep vacuum
2. Triple vacuum
For the purpose of demonstration and masters. Use Deep Vacuum, reason triple vacuum will not
remove all moisture. Only Deep Vacuum than can vaporize and remove moisture, air perfectly.
Practical Session
Step 1
Evacuation of contaminant
Sequential steps/Task
1. Connect the manifold gauge with the hose the high side of the system.
2. Connect the charging hose to the refrigerant bottle via the service valve (if it is industrial
unit).
191
3. Connect the centre hose on manifold to vacuum pump.
4. Connect vacuum pump to electric power socket.
5. Open valve of the service manifold from the high side of the compressor.
6. Close the service valve to the charging refrigerant bottle.
7. Start the vacuum pump and allow to run until the manifold gauge indicate 500 microns
(29.98").
8. Stop drawing vacuum and for 5 minutes to ensure that all the moisture is totally
evaporated.
9. Check for the stable gauge:-rise pressure indicates leakage in the system, stable pressure
indicates no leakage
10. Pressurize system with refrigerant by opening refrigerant bottle and valve on gauge
connecting refrigerant bottle
11. Leak test using either soap or electronic leak detector
12. Repair leakage if found by brazing or sealing, depending on location
13. Carry out performance test, if gauge indicate steady pressure, change accurate quantity of
refrigerant, test for efficient performance through condensing and evaporator temperature
192
MODULE C
NAME OF THE MODULE: Trouble Shooting Electrical Panel
SPECIFIC OBJECTIVE: At the end of the training, trainee should be able to:
1. Select equipment/tools for trouble shooting
2. Isolate panel and read wiring diagram through identification wiring color code/number
3. Use meter to test components and interpret meter reading
4. Test burnt compressor
5. Replace burnt compressor
Introduction
Trouble-shooting electrical panel of Refrigeration and Air-conditioning involves use of
Avo-meter or am- probe meter to test electrical components such as relay, capacitor, fuses, and
compressor.
Successful operation of trouble-shooting electrical requires that you familiarize yourself
to the electrical panel to be able to identify the wring code and terminals.
Practical Session
Selection of Equipment/Tools
Am-probe meter
Avo-meter
Screw driver
Workman Thermometer
Plier combination (insulated set)
Scaffold
Fire extinguisher
Split air-conditioner
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Refrigerator
Practical Session
Trouble-shooting electrical panel
Step 1: Sequential steps/task
1. Isolate the panel power source by opening panel and remove fuse from ,main box
2. Read wiring diagram on panel cover plate or manual
3. Locate and identify wiring color/number and record
4. Use meter leads to test terminals of:-
Capacity
Relay
High and low pressure control
Fuse ends
5. Read resistance as indicated on the meter, reflection of meter to the right and resting on a
definite resistance value indicates okey, while reflection to the left or no reflection
indicates not okay.
Step 2: Test and confirm burnt compressor
1. Remove terminal wires from compressor terminal expose the common, starting and
running terminal.
2. Use meter lead to touch two terminals
3. Leave meter lead on one terminal and move one to the next terminal
4. Observe meter reading
5. If meter reading indicate normal reading, leave one lead on terminal and move the other to
touch a bare part of the compressor
194
6. Observe meter reading, if meter reads positive , it is an indication that the compressor is
burnt and is reading to earth
7. Replace burnt compressor by:-
i. Recover refrigerant
ii. Heat up compressor joints with oxygen/acetylene flame
iii. Install new compressor
iv. Braze joints
v. Evacuate system
vi. Charge refrigerant
vii. Carry out performance test by reading evaporator temperature using work man
thermometer
195
MODULE D
NAME OF THE MODULE: Recovery/Recycling
SPECIFIC OBJECTIVE: By the end of the training, trainee should be able to:
1. Explain the concept of recovery and recycling
2. Observe precautions needed for recovery/recycling
3. Identify system refrigerant
4. Select equipment for recovery/recycling
5. Connect system for recovery/recycling operation
6. Record weight of cylinder(empty) after recovery
7. Recovery/recycling refrigerant
8. Store recovered refrigerant
Introduction
Recovery/recycling is carried out when the system is to under servicing and repair. The
system refrigerant especially chlorofluorocarbon(R-11, R-12) and hydrochlorofluorocarbon
refrigerant in order to avoid emission that will result depletion of the ozone layer. Secondly, to
manage refrigerant in order to avoid wastage.
Recovery involves removal of refrigerant in any condition from the system and storing it
in an external container without necessary testing or processing if in any way, while recycling is
filtration of the recovered refrigerant by passing it many times through a filter drier in the
machine before stage
Concept of Recovery/Recycling
Recovery/Recycling is carried out in order to prevent emission due to:
1. Accidental leak
2. Replacing burnt compressor
196
3. Intrinsic leak
Precaution Needed for Recovery/Recycling
1. Do not overfill cylinder used for recovery
2. Do not mix different types refrigerant
3. Label content of cylinder on the cylinder
4. Use non contaminated cylinder by oil the, acid and moisture
5. Regularly pressure test cylinder and carry out visual check on it.
6. Liquid and gas valves should be separated by color.
7. Wear protective glove/cloth
8. Use quality hose.
9. Do not roll cylinder.
10. If reclaiming is required, contact reclaiming agency.
Practical Session
Step 1: Identify System Refrigerant
Identify system refrigerant through
1. Using refrigerant identifier.
2. Refrigerant stamp on unit data plate.
3. Thermostatic expansion valve indicator for specific refrigerant by design.
4. Standing pressure meant for specific refrigerant on system manual.
Step 2: Selection of Equipment
1. Recovery/Recycling machine.
2. Electronic refrigerant weighing scalp.
3. Recovery valve.
197
4. Service hose.
Step 3: Connection of system for Recovery/Recycling
1. Connect one service those to discharge service port of compressor.
2. Connect another Host to recovery machine outlet port.
3. Connect another Host to liquid valve of the recovery cylinder.
4. Connect center Host from manifold gauge to inlet part of recovery/recycling machine.
5. Connect piercing valve (if domestic unit)
Step 4: Record weight of Recovery cylinder
1. Use an accurate dial or electronic refrigerant scale.
2. Put the recovery cylinder on the scale before recovery.
3. Record weight of cylinder before recovery.
4. Record weight of cylinder after recovery.
5. Subtract weight after from weight before to have accurate value of recovered
refrigerant.
Step 5: Operate Recovery/Recycle machine,
1. Turn off refrigerating system.
2. Close discharge valve.
3. Open recovery cylinder valve.
4. Put on recovery/recycling machine.
5. Allow to run until gauge reads 15 mg of vacuum.
198
MODULE E
NAME OF THE MODULE: Retrofitting Alternative Refrigerant
SPECIFIC OBJECTIVE: By the end of the training, trainee should be able to;
1. Re-appraise factors before retrofit
2. Re-appraise preliminary work to be done before retrofitting
3. Connect recovery/recycling machine.
4. Recover existing chlorofluorocarbon (CFC) and Hydro fluorocarbon (HCFC) refrigerant.
5. Drain existing mineral oil in the system.
6. Replace mineral oil with polyester oil.
7. Change non compatible component.
8. Evacuate and charge system with alternative refrigerant.
9. Test run.
10. Prepare and fix retrofit cable.
Introduction
Retrofitting technology is the art of replacing corresponding ozone friendly refrigerant
with ozone depleting refrigerant in a system that still have long life expectancy. Retrofitting
involves changing some component that are not compatible with the drop-in refrigerant.
Re-appraisal of factors to be considered before retrofitting
1. Alternative refrigerant cost.
2. Availability of alternative.
3. Expect life of exiting system.
4. History of refrigerant leakage of the system.
199
Re-appraisal of preliminary work before retrofitting.
1. Examine existing system on pumping rate, piping condition.
2. Determine history of refrigerant leaks on the system.
3. Record information on system components.
4. Establish existing system operating condition (pressure, temperature, amperage) to determine
baseline operation.
5. Confirm all existing component for compatibility with alternative refrigerant.
6. Check for leakage and repair.
Practical Session
Step 1: Connection of recovery/recycling machine
Identify system refrigerant through
1. Using refrigerant identifier.
2. Refrigerant stamp on unit data plate.
3. Thermostatic expansion valve indicator for specific refrigerant by design.
4. Standing pressure meant for specific refrigerant on system manual.
5. Record weight of recovery bottle
6. Drain existing mineral oil
7. Measure quantity of oil drained and compare with recommended quantity charged to
determine quantity remaining.
8. Replace mineral oil with recommended quantity of polyester oil to be changed.
9. Charge CFC-12 and polyester oil (for about 48 hours).
10. Drain the polyester oil and recover refrigerant, note quantity of oil removed.
200
11. Repeat charge of CFC-12 and polyester oil three times to ensure that 99 to 95% of the
mineral oil is removed and drained
12. Change non compatible components
Thermostatic Expansion Valve (Industrial)
Drier, use either molecular sieve, xi+-9 or xi+-7 as recommended
Evacuate system by:
11. Connect the manifold gauge with the hose the high side of the system.
12. Connect the charging hose to the refrigerant bottle via the service valve (if it is industrial
unit).
13. Connect the centre hose on manifold to vacuum pump.
14. Connect vacuum pump to electric power socket.
15. Open valve of the service manifold from the high side of the compressor.
16. Close the service valve to the charging refrigerant bottle.
17. Start the vacuum pump and allow to run until the manifold gauge indicate 500 microns
(29.98").
18. Stop drawing vacuum and for 5 minutes to ensure that all the moisture is totally evaporated.
19. Check for the stable gauge:-rise pressure indicates leakage in the system, stable pressure
indicates no leakage
20. Pressurize system with refrigerant by opening refrigerant bottle and valve on gauge
connecting refrigerant bottle
21. Leak test using either soap or electronic leak detector
22. Repair leakage if found by brazing or sealing, depending on location
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23. Carry out performance test, if gauge indicate steady pressure, change accurate quantity of
refrigerant, test for efficient performance through condensing and evaporator temperature
24. Charge with alternative refrigerant
Note: do not over charge 90% by weight of CFC as recommended.
25. Check for leakage using soap or electronic leak detector.
26. Test run- startup system and monitor the evaporator super heat for proper evaporation.
27. Prepare retrofit label
Name of Oil Manufacturer…………………………………………………..
PIN Oil Part Number by Manufacturer……………………………………..
Name of Refrigerant Charge………………………………………..………
Quantity Charge…………….. Retrofiller…………………………………..
Name of Establishment……………………………………………………..
Date of Retrofitting…………………………………………………………
Address of Client…………………………………………………………….
City……………………………………………Invoice No…………………
DO NOT REMOVE!
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MODULE F
NAME OF THE MODULE: Commissioning
SPECIFIC OBJECTIVE: By the end of the training, trainee should be able to;
1. Carry out visual check on the following to confirm standard of operation and fault on fittings
and component.
2. Adjust poorly installed components and fittings
3. Check and correct electrical wiring on panel
4. Check and adjust refrigerant charge
5. Read interpret and adjust safety devices such as temperature, pressure control
6. Record operating condition
Introduction
Commissioning is an essential procedure that is usually undertaken to verity proper functioning
of the plant after installation in order to ensure safety and system standard performance of
operation. This is done through series of tests and adjustment with record performance. Sate of
the entire plant as guide for official operation and maintenance.
Practical Session
Trainee taken to excursion to industrial plant or use of split air-condition.
Sequential steps/ Task:
Carry out visual check on the following to confirm standard and fault
1. Pipe work tightness and appropriate valve fitting.
2. Safety device and calibration
3. Sight glass, drier standard and heat exchanger
4. Pressure gauge fitting
5. Provision of liquid receiver
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6. Provision of water system
7. Component such as compressor security bolt, oil level, pulley coupling alignment
8. Belt tension
9. Motor and control
Step 2: Adjust all under standard installation as found
Step 3: Check and correct electrical wiring such as;
1. Motor control circuit
2. Enshrouded live component within panel
3. Switchgear cleanness
4. Dryness cleanness of surrounding
5. Correctness on internal links on starter
Step 4: Check refrigerant charge
1. Check leakage
2. Adjust refrigerant charge to standard
Step 5: Check and adjust safety devices such as
1. High pressure gauge
2. Low pressure gauge
3. Thermometer temperature control
Step 6: Record operating conditions
1. Evaporator temperature
2. Condensing temperature
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Appendix V
UNIVERSITY OF NIGERIA, NSUKKA
DEPARTMENT OF INDUSTRIAL TECHNICAL EDUCATION
REFRIGERATION AND AIR -CONDITIONING \PSYCHOMOTIVE R ATINGS
SCALE (RAPRS)
Part one
Please complete the information below as appropriate
Name of Trainer: ……………………………………
Location of Training: ……………………………….
Skill Evaluated: …………………………………….
Date: ………………………………………………..
Time: ……………………………………………….
Purpose of Rating Scale
The purpose of rating is to help the trainer and trainee determine the level at which the
trainee have learnt the expected skills in Refrigeration and Air-conditioning by the industry.
Instruction for Raters
There are 4 columns of level of competency of each skill to be rated.
Please rate each trainee accordingly, by direct observation during trainee practical session. The
response options on the scale are a follows:
4 Very High Performance (VHP)
3 High Performance (HP)
2 Moderate Performance (MP)
1 Low Performance (LP)
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RATING SCALE ON LEAK DETECTION MODULE
S/N
Skills to be
Evaluated
Evaluation Criteria
Low
Performance
(LP)
1
Moderate
Performance
(MP)
2
High
Performance
(HP)
3
Very High
Performance
(VHP)
4
1. Ability to select equipment and material for leak detection
Not able to select equipment as per task
Few equipment selected as per task
Most equipment selected as per task
All equipment selected as per task
2. Ability to use soap solution to test leakage
Not able to determine quantity of soap and water as per task
Quantity of soap correctly measured but water wrong as per task
Quantity of both water and soap correct but slow as per task
Quantity of soap and water correct and appropriate to set time as per task
3. Ability to swap soap at piping’s joints
Not able to identify joints with soap as per task
Able to identify few joints to swap as per task
Able to identify all joints but not fast as per task
Fast and accurate to swap joints as per task
4. Ability to use mirror to view symptoms of leakage
Not able to use mirror to interpret symptoms of leakage as per task
Able to view joints to bubble but could not interpret as per task
Able to view but could not interpret fast bubble as per task
Able to view and interpret all size and forms of bubble fast as per task
5. Ability to use electronic leak detector to leak test leakage by: Ability to start electronic leak detector by turning the knob on and allow to warm for one minute away from refrigerating system
Not able to turn on the knob as per task as per task
Able to turn on the knob but could not wait for one minute as per task as per task
Able to turn on the knob waited for one minute but could take it away from the system as per task as per task
Able to turn on the knob, waited for one minute and take it away from the system as per task as per task
6. Ability to probe joints with detector by slowly run sensing tip closely around suspected areas
Could not probe joint as per task
Able to probe joints but not all suspected joints as per task
Able to probe all suspected joints but not slowly as per task
Abel to probe all suspected joints and slowly as per task
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7. Ability to identify symptoms of leakage by adjusting of sensitivity knob, increase in tickling noise indicate level of leakage
Could not adjust sensitivity knob to identify leak level as per task
Able to adjust sensitivity knob but could not interpret leak level as per task
Able to adjust sensitivity knob and interpret leak level but not fast as per task
Able to adjust sensitivity knob and interpret leak level fast as per task
8. Ability to connect dye can at the low side through manifold gauge
Not able to connect dye can to low side of the system as per task
Able to connect dye can to low side of the system and release dye into the system bud take long time as per task
Able to connect dye can to low side of the system and released dye into the system but taken a shorter time as per task
Able to connect dye can to the system and release dye into the system perfectly and fast as per task
9. Ability to connect ultra violet light for leak detection
Not able to identify service port for connection of ultra-violet light as per task
Able to identify service part connect ultra-violet light, start system but with several attempt as per task
Able to identify service part connect ultra-violet light, start system but with few attempt as per task
Able to identify service part, connect ultra-violet light and start system perfectly on time as per task
10.
Ability to locate leaking spot with system of leak with light glow
Able to locate few leaking spot with light glow as per task
Able to locate most leaking spot with light glow but slowly as per task
Able to locate almost all leaking spot with light glow but not to time as per task
Perfect location of leaking spot with light glow ad appropriate to time as per task
11. Ability to light halide touch, operate for identification of leak
Not able to light touch and operate according task as per task
Able to light touch and operate according to few task as per task
Able to light touch and operate according to most task as per task
Ability to light to light touch and operate according to all the task as per task
12. Ability to identify symptoms of leak with halide touch
Not able to identify symptom of leakage with halide touch as per task
Able to identify only symptoms of small leakage as per task
Able to identify both symptom small and large leakage but with longer time as per task
Able to identify both symptoms small and large leakage but with shorter time as per task
13. Ability to connect nitrogen and charge for leak detection
Not able to perform task to connect and charge nitrogen for leak detection as per task
Able to perform few task to connect and charge nitrogen for leak detection as per task
Able to perform most tasks to connect and charge nitrogen for leak detection as per task
Able to perform all task to connect and charge nitrogen for leak detection as per task
207
RATING SCALE ON EVACUATION OF CONTAMINANT MODULE
S/N
Skills to be
Evaluated
Evaluation Criteria
Low
Performance
(LP)
1
Moderate
Performance
(MP)
2
High
Performance
(HP)
3
Very High
Performance
(VHP)
4
1. Ability to select equipment for evacuation of contaminants
Not able to select equipment as per task
Some equipment selected correctly as per task
Most equipment selected correctly as per task
All equipment selected correctly as per task
2. Ability to connect vacuum pump/ manifold gauge to the system
Not able to connect vacuum pump/ manifold gauge as per task
Able to connect only manifold gauge to high side of the system as per task
Able to connect manifold gauge and one service hose only as per task
Able to connect both manifold gauge and vaccum pump to the system as per task
3. Ability to run vacuum pump to satisfaction
Not able to run vacuum pump to satisfaction as per task
Able to perform few task to run vacuum pump to satisfaction as per task
Able to perform most task to run vacuum pump to satisfaction as per task
Able to perform all task to run vacuum pump to satisfaction as per task
4. Ability to read gauge for moisture presence in the system
Not able to perform task gauge reading for moisture presence as per task
Able to perform few task on gauge reading for moisture presence as per task
Able to perform most task on gauge reading for moisture presence as per task
Able to perform all task on gauge reading for moisture presence as per task
5. Ability to pressurize system for checking of leakage
Not able to pressurize system as per task
Able to pressurize system as per few task
Able to pressurize system as per most task
Able to pressurize system as per most task
6. Ability to repair leaks when found
Not able to repair leak as per task
Able to repair leaks with few skill in brazing and could not apply sealing to where needed as per task
Able to repair leaks with most skills on brazing but could not apply sealing to where needed as per task
Able to repair with competent skill in brazing and application of sealing to where needed as per task
7. Ability to carry out performance test
Not able to carry out performance test as per task
Able to carry out performance test as per few task
Able to carry out performance test as per most task
Able to carry out performance test as per all task
208
RATING SCALE ON TROUBLE-SHOOTING ELECTRICAL PANEL
S/N
Skills to be
Evaluated
Evaluation Criteria
Low
Performance
(LP)
1
Moderate
Performance
(MP)
2
High
Performance
(HP)
3
Very High
Performance
(VHP)
4
1. Ability to identifying needed tools
Able to identify few tools needed as per task
Able to identify most tools needed as per task
Able to identify almost all tools needed as per task
Able to identify all tools needed as per task
2. Ability to isolate panel and read wiring diagram
Not able to isolate panel and read wiring diagram as per task
Able to isolate panel but could not read wiring diagram as per task
Able to isolate panel and not able to read wiring diagram completely as per task
Able to isolate panel and read wiring diagram completely as per task
3. ability to identify wiring colour code/ number as per terminal connection
Not able to identify wiring colour code/ number as per terminal and connection as per task
Able to identify wiring colour code/ number as per terminal and connection but slowly as per task
Able to identify colour code/ number as per terminal and connection but in less time as per task
Able to identify colour code/ number as per terminal and connection in shortest time as per task
4. Ability to use meter to test components for continuity and interpret meter reading
Able to test some component and interpret meter reading as per task
Able to test most component and interpret meter reading as per task
Able to test almost all components and interpret meter reading as per task
Able to test all components and interpret meter reading as per task
5. Ability to test and identify symptom of burnt compressor
Not able to test compressor terminals as per task
Able to test compressor terminals but could not identify symptom of burnt compressor as per task
Able to test compressor terminals and identify symptom of burnt compressor with slower time as per task
Able to test compressor terminals and identify symptoms of burnt compressor with shorter time as per task
6. Ability to replace burnt compressor
Not able to carry out steps for replacement of burnt compressor as per task
Able to carry out few steps for replacement of burnt compressor as per task
Able to carry out most step for replacement of burnt compressor as per task
Able to carry out all steps for replacement of burnt compressor as per task
209
RATING SCALE ON RECOVERY/ RECYCLING MODULE
S/N
Skills to be
Evaluated
Evaluation Criteria
Low
Performance
(LP)
1
Moderate
Performance
(MP)
2
High
Performance
(HP)
3
Very High
Performance
(VHP)
4
1. Ability to identify recovery/recycling equipments
Not able to identify recovery/recycling equipments as per task
Able to identify most recovery /recycling equip-ments as per task
Able to identify almost all recovery /recycling equip-ments as per task
Able to identify all recovery/recycling equipments as per task
2. Ability to identify system refrigerant
Not able to identify system refrigerant as per task
Able to identify system refrigerant as per task
Able to identify system refrigerant as per most task
Able to identify system refrigerant as per all task
3. Ability to connect recovery/recycling machine to system and recovery bottle
Not able to connect recovery/recycling machine to system and recovery bottle as per task
Able to connect recovery/recycling machine to system with moderate competency as per task
Able to connect recovery/recycling machine to system with high compet-ency as per task
Able to connect recovery/recycling machine to system with outstanding competency as per task
4. Ability to connect recovery/recycling machine to weigh-ing scale
Low ability to connect recovery /recycling machine to weighing scale as per task
Moderate ability to connect recovery /recycling machine to weighing scale as per task
High ability to connect recovery /recycling machine to weighing scale as per task
Outstanding ability to connect recovery /recycling machine to weighing scale as per task
5. Ability to connect piercing value to domestic system
Low ability to connect piercing value to domestic system as per task
Moderate ability to connect piercing value to domestic system as per task
High ability to connect piercing value to domestic system as per task
Outstanding ability to connect piercing value to domestic system as per task
6. Ability to operate recovery/recycling machine
Low ability to operate recovery /recycling machine as per task
Moderate ability to operate recovery /recycling machine as per task
High ability to operate recovery /recycling machine as per task
Outstanding ability to operate recovery /recycling machine as per task
7. Ability to record weight of recovered refrigerant
Low ability to record weight of recovered refri-gerant as per task
Moderate ability to record weight of recovered refrige-rant as per task
High ability to record weight of recovered refri-gerant as per task
Outstanding ability to record weight of refrigerant as per task
8. Ability to store recovered/recycled refrigerant in special cylinder
Low ability to store recovered/recycled refrigerant in special cylinder as per task
Moderate ability to store recovered /recycled refri-gerant in special cylinder as per task
High ability to store recovered /recycled refri-gerant in special cylinder as per task
Outstanding ability to store recovered /recycled refrige-rant in special cylinder as per task
210
RATING SCALE ON RETROFITTING ALTERNATIVE REFRIGERANT
S/N
Skills to be
Evaluated
Evaluation Criteria
Low
Performance
(LP)
1
Moderate
Performance
(MP)
2
High
Performance
(HP)
3
Very High
Performance
(VHP)
4
1. Ability to connect weighing scale to recovery/recycling machine
Low ability to connect weighing scale to recovery /recycling machine as per task
Moderate ability to connect recove-ry /recycling machine to weigh-ing scale as per task
High ability to connect recovery /recycling machine to weighing scale as per task
Outstanding ability to connect recovery /recycling machine to weighing scale as per task
2. Ability to recover existing CFC/HCFC refrigerant
Low ability to connect weighing scale to recovery /recycling machine as per task
Moderate ability to connect weigh-ing scale to recov-ery/recycling machine as per task
High ability to connect weighing scale to recovery /recycling machine as per task
Outstanding ability to connect weighing scale to recovery /recycling machine as per task
3. Ability to recover existing mineral oil and replace with polyester oil
Not able to recover mineral oil and replace with poly-ester oil as per task
Moderate ability to recover mineral oil but could not replace with polyester oil as per task
High ability to recover mineral oil and replace with polyester oil as per task
Outstanding ability to recover mineral oil and replace with poly-ester oil as per task
4. Ability to identify and change non compatible components
Few ability to identify and change non-compatible components as per task
Ability to identify few non compa-tible components and change as per task
Ability to identify all non compatible components but could not change all as per task
Ability to identify and change all non compatible components as per task
5. Ability to evacuate and charge system with HFC refrigerant
Not able to carry out few steps in evacuation and charge system as per task
Able to carry out most steps in evacuation and charge system as per task
Able to carry out almost all steps in evacuation and charge system as per task
Able to carry out all the steps in evacuation and charge system as per task
6. Ability to test run, test leakage and read (evaporator temperature) super heat and interpret
Able to confirm leakage read ad interpret (eva-porator temperature) super heat and interpret as per task
Able to carry out few. Steps to confirm leakage, read and interpret (evaporator tem-perature) super heat as per task
Able to carry out most steps to con-firm leakage, read and interpret (evaporator temp-rature) super heat as per task
Able to carry out all steps to con-firm leakage, read and interpret evaporator temperature) as per task
7. Ability to prepare and fix retrofit label
Not able to include all necessary data on label and fix at the proper position as per task
Ability to include most necessary data on label and fix at the proper position as per task
Ability to include almost all necessary data and fix at the proper position as per task
Ability to include all necessary data and fix at the proper position as per task
211
RATING SCALE ON COMMISSIONING MODULE
S/N
Skills to be
Evaluated
Evaluation Criteria
Low
Performance
(LP)
1
Moderate
Performance
(MP)
2
High
Performance
(HP)
3
Very High
Performance
(VHP)
4
1. Ability to carry out visual check
Able to carry out visual check and identify faults on few components as per task
Able to carry out visual check and identify faults on most components and piping as per task
Able to carry out visual check and identify faults on almost all components and piping as per task
Able to carry out visual check and identify faults on all components and piping as per task
2. Ability to adjust poorly stall components and fitting
Able to adjust few components and fittings to standard as per task
Able to adjust most component and fittings to standard as per task
Able to adjust almost all components and fittings to standard as per task
Able to adjust all components and fittings to standard as per task
3. Ability to check and correct electrical wiring within panel control circuit and switchgear
Able to check and correct few electri-cal problem as per task
Able to check and correct most electrical problem as per task
Able to check and correct almost all electrical problem as per task
Able to check and correct all electrical problem as per task
4. Ability to check and adjust refrigerant charge
Able to check refrigerant but could not interpret accurate charge as per task
Able to check refrigerant charge and interpret but could not adjust refrigerant charge as per task
Able to check refrigerant charge and interpret with moderate competent to charge accurately as per task
Able to heck refrigerant charge, interpret and charge accurately with very high competent as per task
5. Ability to read interpret and adjust safety devices such as temperature and pressure controls
Not able to read, interpret, adjust safety devices such as temperature and pressure gauge as per task
Able to read, interpret and adjust few safety devices and could not adjust as per task
Able to read, interpret and adjust most safety devices as per task
Able to read, interpret and adjust all safety devices as per task
6. Ability to record operating condition parameters
Not able to record parameters as per task
Able to record few parameters as per task
Able to record most parameters as per task
Able to record all parameters as per task
212
MODULE ON REFRIGERATION AND AIRCONDITIONING
ENTER
MODULE
READ MODULE INSTRUCTION AND GUIDE
SELECT ACTIVITIES
CARRYOUT ACTIVITIES/TEST
80% COMPETENCY ON ALL OBJECTIVES
OK YES SELECT
No
COMPLETE
MODULE
ATTEND SMALL GROUP
SESSION
CONFERENCE OR
INSTRUCTION WITH
RESOURCE PERSON
AND/OR
GO
BA
CK
NO SELECT
TEST
PASS POST-TEST EVALUATION WITH
80% PROFICIENCY NO
GO BACK AND
REPEAT
MOUDLE
YES EXIT
PROCEED TO
ANOTHER
MODULE
COMPLETE
ACTIVITIES AND
PASS POST-TEST
WITH HIGHER
COMPETENCY LEVEL
OF 80% ABOVE
EXIT
SELF-CHECK TEST
Appendix VI
213
OBJECTIVE TEST ON COGNITIVE EVALUATION
1. The following are causes of contaminant in a system except
(a) Air
(b) Oil
(c) Leakage
(d) Moisture
2. The following are reasons for evacuation of contaminant except
(a) Replacement of compressor
(b) Replacement of condenser
(c) Replacement of evaporator
(d) Repairing of leakage
(e) Replacement of door gasket
3. Which among the following is not a concept of recovery/ recycling
(a) Emission due to leakage
(b) Intrinsic leak
(c) Accidental leak
(d) Replacement of major components
(e) Emission due to installation
4. The following refrigerant causes ozone depletion when emitted into the
atmosphere except
(a) R-717
(b) R-22
(c) R-11
(d) R-12
5. Choose among the following that describe the term recovery
(a) Virgin refrigerant processed to quality
(b) System refrigerant remove from the system for re-use or dispose
(c) System refrigerant remove from the system for release to atmosphere
(d) System refrigerant remove for process to remove some solids, moisture
214
OBJECTIVE TEST MARKING SCHEME
20 MARKS EACH
TOTAL WEIGHT 100%
1. B
2. E
3. A
4. B
215
TABLE OF SPECIFICATION FOR CERTIFICATION
SKILL TITLE:
Date Rater Content Skills
evaluated
PSYCHOMOTIVE ASSESSMENT CRITERIA TOTAL
SCORE LP 1-24 MP 25-49 HP 50-74 VHP 75-100
KEY
PAC - PSYCHOMOTIVE ASSESSMENT CRITERIA
LP – LOW PERFORMANCE
MP - MODERATE PERFORMANCE
HP – HIGH PERFORMANCE
VHP – VERY HIGH PERFORMANCE
216
Appendix VII Try-out of modules analysis
Univariate Analysis of Variance
Tests of Between-Subjects Effects
Dependent Variable: finalrating
Source Type III Sum of
Squares
df Mean Square F Sig.
Corrected Model .028a 1 .028 1.208 .023
Intercept 30.499 1 30.499 1315.720 .000
initialrating .028 1 .028 1.208 .023
Error .533 23 .023
Total 375.185 25
Corrected Total .561 24
a. R Squared = .050 (Adjusted R Squared = .009)
217
Appendix VIII RESULT OF ANALYSIS OF NEED ASSESSMENT USING SPSS
218
RESEARCH QUESTION 2
219
220
221
222
223
224
225
226
Appendix IX
RELIABILITY OF INSTRUMENT
227
228
229
230
Analysis of pilot testing
Kendall's W Test
Ranks
Mean Rank
Student1 7.00
Student2 6.00
Student3 7.00
Student4 7.17
Student5 5.50
Student6 7.17
Student7 5.50
Student8 5.50
Student9 5.50
student10 8.67
Test Statistics
N 3
Kendall's Wa .710
Chi-Square 15.100
Df 10
Asymp. Sig. .128
a. Kendall's Coefficient of Concordance
231
Appendix X
NBTE CURRICULUM FOR REFRIGERATION AND AIR-CONDITION ING
232
233
234
235
236