Department of Engineering
(CCATS)
By
In Partial Fulfillment of the Requirements
For the Degree of
Dr. Ben Abbott INSTRUCTOR OF ELECTRICAL ENGINEERING
Sponsor Lead:
i
ABSTRACT
Calorimetry is the process of measuring the heat exchange within a chemical reaction or
other process. A calorimeter is a device that performs such a function. Existing calorimeters
include adiabatic, reaction, bomb, etc. The goal of this senior design project is to design and build
a testing apparatus (calorimeter) to measure the efficiency and performance of
evaporating/condensing coils. Coils like these are found within air conditioning units and serve to
absorb heat from surrounding air. These coils are typically filled with refrigeration coolants, and
when working in conjunction, performance is quite effective. Depending on the manufacturing
process, the raw materials and other processes that deal with turning a coil into a finished product
have plenty to do with the efficiency of the coil itself. Our testing instrument aims exactly at this,
testing which supplier provides the most efficient coils.
Friedrich Air Conditioning is a local San Antonio company that was founded in 1883. They
pride themselves on quality, reliable, and efficient air conditioning products. The engineering
department at St. Mary’s University have teamed up to help starting engineers develop systems to
answer industries’ needs. There are currently no products in the market that perform the coil
calorimeter tasks to the specificity of Friedrich. Our team’s aim was to provide Friedrich an
efficient and reliable calorimeter system to enhance their ability to test finer aspects of their A/C
units. Friedrich’s could only test how the coils performed when they were attached to the air
conditioning unit. This made it difficult to measure the coils performance independently. Testing
the coil as a whole A/C unit can take up to 5 hours to perform. The calorimeter designed and
implement isolates and focus strictly on the coils at hand and is capable of cutting the previous
method of coil testing time by nearly 75%.
ii
This report provides details on the senior design team’s develop process and descriptions
of system developed for Friedrich’s coil performance testing. We provide Computer-Aided Design
(CAD) drawings specifying the dimensions and tolerances pertaining to the system’s mechanical
structure and wiring, flowcharts, Human Interface (HMI) programming to cover the calorimeter’s
and operations.
iii
ACKNOWLEDGMENTS
We would like to send a cordial acknowledgment to the individuals that day-in and day-
out continue to guide us throughout the entirety of this process. These efforts should not be taken
by any means lightly, as they have molded the future of this project as well as our persona. We
have been pushed to grow as professionals in the making and we do not see ourselves
accomplishing this to such an extent if it were not for the help of these individuals. For this reason,
our most sincere and heart-warming acknowledgments go out to these gentlemen: Lionel Lopez,
Rene Esqueda, Dr. Juan Ocampo, Dr. Ben Abbott, and Vernon Wier.
iv
4. Senior Design Gantt Chart ........................................................................................................6
5. Systems Engineering Application ………...............................................................................12
6. Concept of Operations ............................................................................................................13
7. Requirements and Architecture ..............................................................................................18
8.3 Frame Design …………………………………………………………………………….38
8.3.2 Finite Element Analysis ……………………………………………………………44
8.4 Air Sampler Design ………………………………………………………………………46
8.5 Heat Exchanger …………………………………………………………………………..49
8.6 Thermodynamics ………………………………………………………………………...52
v
8.8.5 Three-way actuated ball valve ……………………………………………………..66
8.8.6 Water Chiller ……………………………………………………………………….68
8.8.7 Water Heater ………………………………………………………………………..70
11.1 Problem 1 ……………………………………………………………………………….76
11.2 Problem 2 ……………………………………………………………………………….78
12. SMC Capstone Reflection .......................................................................................................79
13. Appendices ……………..........................................................................................................82
13.4 Appendix D: Framing Components SolidWorks Drawings …………………………...96
13.5 Appendix E: Miscellaneous Images from Fabrication Process ………………………101
14. References ………………………………………………………………………………….111
Figure 2: Senior Design Gantt Chart .........................................................................................9
Figure 3: Date Tracking Gantt Chart .......................................................................................10
Figure 4: Senior Design Task List ...........................................................................................11
Figure 5: System Engineering V Model ..................................................................................12
Figure 6: Initial Concept Drawings …......................................................................................15
Figure 7: Initial Top-Level Concepts of Operation .................................................................16
Figure 8: Power Consumption Chart........................................................................................17
Figure 10: Top-Level Water Flow ...........................................................................................19
Figure 11: Project Requirements List ......................................................................................20
Figure 12: CCATS Graph User Interface Screen View ...........................................................22
Figure 13: CCATS Data Lag List ...........................................................................................23
Figure 14: Crimson Software Development Data Tags ...........................................................24
Figure 15: Testing Program Crimson Development................................................................25
Figure 16: HMI Display Home Page .......................................................................................26
Figure 17: HMI Display Test Settings .....................................................................................27
Figure 18: HMI Display Test Menu.........................................................................................28
Figure 19: HMI Display Data Logger ......................................................................................28
Figure 20: HMI Display System Status ...................................................................................29
Figure 21: HMI Display Shutdown ..........................................................................................30
Figure 22: Control Box ............................................................................................................31
Figure 25: HMI I/O Panel Wire Schematic .............................................................................34
Figure 26: Inside of Control Box ............................................................................................35
Figure 27: CCATS Version 1 Design Testing Apparatus Breakdown ...................................36
Figure 28: Frame #7 Finite Element Analysis (FEA) ..............................................................37
Figure 29: Frame #8 Finite Element Analysis (FEA) ..............................................................38
Figure 30 First Iterations of the Frame ....................................................................................39
Figure 31: Final Frame Iteration ..............................................................................................40
Figure 32: Final Frame Isometric View ...................................................................................41
Figure 33: Final Frame Top View ...........................................................................................41
Figure 34: Final Frame Right View .........................................................................................42
Figure 35: CCATS Free-body Diagram ...................................................................................43
Figure 36: Finite Element Analysis .........................................................................................45
Figure 37: Air Sampler #1 ......................................................................................................46
Figure 38: Air Sampler #1 (SolidWorks) .................................................................................47
Figure 39: First Iteration - Air Sampler #2 ..............................................................................48
Figure 40: Final Iteration - Air Sampler #2 .............................................................................49
Figure 41: Water Heater Design ..............................................................................................50
Figure 42: Water Heater...........................................................................................................50
Figure 45: Waterflow Diagram ................................................................................................55
Figure 47: Mass Flow Rate Experiment ..................................................................................63
Figure 48: Walrus GPD25-10SFC Pump .................................................................................65
Figure 49: Endress + Hauser Promass 83E Coriolis flowmeter ..............................................66
Figure 50: 20 Gallon Water Reservoir .....................................................................................68
Figure 51 Deelat Three-way Ball Valve ..................................................................................70
Figure 52: Coaxial Heat Exchanger .........................................................................................72
Figure 53: Friedrich Water Chiller ..........................................................................................72
Figure 54: Heating Rod ............................................................................................................73
ix
Table 2: Fluid Calculations ......................................................................................................60
1
Friedrich Air Conditioning currently seeks to introduce an independent condenser and
evaporator coil validation process into their manufacturing operation. Independent testing
provides a side-by-side measurements and comparisons of their coil’s performance metrics. The
only way Friedrich can currently determine the efficiency of their coils is by performing actual
tests on whole units which consumes way too much time and is rather costly. The goal of the
project is to design and build a self-contained heat exchanger calorimeter that meets ASHRAE
specifications required of our sponsor (Friedrich) to help them maintain their principles of quality,
reliability, and efficiency. These shared values are at the core engineering and drove the
development of our project.
1.1. COMPANY DESCRIPTION
Friedrich Air Conditioning Co. is a San Antonio based multinational air conditioning
design and manufacturing company. Friedrich was founded on the values of using science to
enhance the comfort and quality of life of people. So, it may come as no surprise why our team
was inspired by Ed Friedrich’s vision and creative passion toward helping make peoples’ day a bit
more enjoyable. The founder’s resourcefulness and craftsmanship in creating pleasant atmospheres
first made Friedrich a Longhorn Texas furniture household name. But living in Texas is hot and
as developments in refrigeration science began to show promise in helping bring improvements to
people’s lives Friedrich dedicated the business’s efforts towards exploiting the leveragability of
refrigeration to improve people’s quality of living. Since 1883 Friedrich has been dedicated
towards providing skillfully crafted high quality cooling and heating products to help people create
and enjoy their own oasis in the comfort of their homes. Friedrich is Headquarters here in San
Antonio and has their environmental unit manufacturing facility based in Mexico. Friedrich’s deep
2
roots in the San Antonio area and commitment to quality has allowed Friedrich to sustain and build
their operations in North America while all their competitors have had to outsource the
manufacturing from overseas countries. Friedrich’s dedication and reputation of bringing people
high quality comfort has encouraged our team and Saint Mary’s University to build a solid
partnership with Friedrich to help both our organizations strengthen our commitments to helping
others through engineering.
1.2. PROBLEM STATEMENT
Friedrich’s entrenched commitment to providing people a higher quality of living spurred
the construction of the research and development center here in San Antonio, Texas. It is in this
facility where their products are designed and tested on their ability to produce comfortable living
environments. Friedrich operates on their knowledge of thermodynamic and engineering science
to raise efficiency, reliability, and quality of their environmental control units. Under the hood of
these units are engineered components that allow us to utilize the leveragability of thermal energy
exchanges to create desired to environmental atmospheres outputs. The most important of these
heat exchanges happens inside the unit’s coils. It is in the units’ coils where we find the greatest
diffusion of thermal energy and it is this energy exchange that turns hot air cold and cold air hot.
Our project is focused on independently testing the various coil designs’ abilities to diffuse thermal
energy and to help Friedrich determine which coils perform the best. Currently, Friedrich must test
the whole environmental control unit to capture and rate the unit's thermal energy exchanging
performance; our project aims to helps them take a deeper look into how their unit’s most critical
component is performing. This hardware-in-the-loop testing capability would enhance Friedrich’s
3
ability to determine which coil designs meet high-quality standards and provide insight into the
capabilities of future manufactured products.
1.3. OBJECTIVE
The overall goal of our senior design project is to timely provide Friedrich an industry standard
calorimeter that provides precise and accurate hardware in the loop testing capabilities for
evaluating the performance of a wide range of various coil designs. Testing systems of this caliber
require a great deal of engineering to ensure the data they output is viable, making this is our most
critical project requirement. Just as important as the data accuracy was the deadline objective of
delivering Friedrich a complete and working calorimeter by 01 April 2021. These were the main
two objectives our team has worked to complete since mid-August of 2020. More finer objectives
of the system design were led by Friedrich’s Head of Engineering and esteemed Rattler Alumni
Lionel Lopez. Some of the main requirements Friedrich’s desired were that the system be easily
transportable and shall fit inside the research and development’s Rain Test Room, which has a
doorway with dimensions 80 x 30 inches. There were also power requirements for the system
including being able to extend power out to the middle of the research and development testing
floor. Project requirements were listed clearly by the team’s sponsor. Some requirements defined
the system shall interface with Friedrich’s Air Tunnel System code name Bertha for the huge
breathes of tunneled air the system generates. Alongside the Friedrich led requirements were the
additional safety, health, and code requirement of our local government. To ensure all the
objectives of our project were met in a timely manner and we employed a system development
and time management tool.
4
In order to provide Friedrich with an industry standard calorimeter system that would help
improve the efficiency of their products, our team proposed the development of the coil calorimeter
automated testing system (CCATS). CCATS is a revision of a 2019-2020’s St. Mary’s University’s
Calorimeter Senior Design Project which was halted in development due to the COVID 19
pandemic. The overall higher-level concept behind CCATS operations can be seen as an analogy
for a similar energy transfer measuring test. Let say for example we have a cup of liquid place
under a burner, and we measure the amount of fuel that was consumed to bring the liquid to a boil.
Next, if we repeat the test under the same conditions as the first but only change the cup the liquid
is sitting in, we can determine which cup is better at transferring thermal energy from the burner
to the liquid by measuring the amount of fuel left after each test. CCATS will work off this
fundamental principle of energy diffusion and create a controlled environment where air and water
flow rates and temperatures, as well as water pressure within the testing system, will be recorded
and analyzed to capture a coil’s ability to diffuse energy and transfer heat from the air to the coil
and from the coil to the air. The CCATS environmental control and data recording automation is
driven by programmable logic and Proportional Integral and Derivative (PID) controllers that have
adjustable initial test settings that can be inputted by the operator conducting a test on a coil. Our
proposed hardware in the loop testing system solution is aimed at providing Friedrich a precise
and accurate calorimeter to independently measure the thermal energy diffusion rates of a coil
being tested. To ensure the precisions of CCATS measurements all tests with identical setting
shall render identical outputs within a limited tolerance set by the American Society of Heating,
Refrigerating and Air-Conditioning Engineers (ASHREA) standards, to ensure the accuracy of
CCATS the error between indicated values and the true value of temperatures being record shall
be within established ASHREA tolerances found in ASHREA 41.1/ 41.2. CCATS ability to create
5
repeatable controlled environments and deliver accurately record data from the tested coil will
provide Friedrich with a viable solution to judging the performance of coil designs. Figure 1 below
shows a Computer Aided Design (CAD) drawing of the CCATS system iteration.
CCATS CAD Drawing
Figure 1: CCATS CAD Drawing
This CAD drawing of CCATS help illustrate what the overall system design looks like in
the lower chamber are the environmental control components, in the top right chamber is the
testing chamber, and the blue chamber houses electric power and system controls.
6
2. OVERVIEW OF SYSTEM
The system breaks down into 3 different chambers: Environmental control chamber, unit
testing chamber and electrical chamber. To start off, the environmental control chamber oversees
the thermodynamics, heat transfer and fluid analysis of the system. This chamber houses many of
the components that make up CCATS and takes up the bottom half of our device. The most
important job to be performed includes the heating, cooling, and transportation of our fluid, which
for this device is water. A water reservoir alongside a heating rod, a chiller and pump work together
to perform such task.
In the system after the fluid has been cycled through these subcomponents and a desired
water temperature and flow rate has been reached in coil the testing measurements begin to be
recorded. Inside the testing chamber is where all the calorimeter measurements take place. Inside
the testing chamber the coils being testing gets locked into position and our heated/cooled fluid is
ran through the coil. Air is pulled threw the coil by a stand alone air flow meter named Bertha.
Bertha works as an air suctioning device which mates to CCATS in an effort to determine mass
air flow being pushed through our testing coils.
The measurements of the fluid’s temperature and pressure running through the coil is set
into the Redlion HMI to perform the coil efficiency recordings. The HMI is located in the electrical
chamber of the calorimeter. The electrical chamber is the user’s best friend. This is the part of the
system that talk back to the operator and ties everything together. Here we can monitor the fluid
in the environmental control chamber and the air running through the testing chamber. Through
the electrical chamber, the user communicates with CCATS and ultimately decides whether a coil
can be put into production or not. It is this chamber that answers the ultimate question this device
test: Is the coil efficient? The electrical chamber puts the ribbon on the prize.
7
3. SUMMARY OF ENGINEERING METHOD
One of the luxuries afforded to the engineering students as part of the Saint Mary’s Senior
Design teams is the students are allowed and encouraged to choose a project that we wanted to
work on. The teams were challenged to find a project that would allow us to showcase the master
hood of our engineering skills by delivering a real-world engineering solution to real world
problems faced by today's engineers in industry. Our team saw that we would be able to showcase
our systems engineering skills and create a viable engineering solution to meet Friedrich desire to
find accurate data on different coil designs thermal diffusion performance.
As in all engineering projects, an engineering method must be followed. Our teams used
system and project development tools including Gannt Charts, “V” models and tasking lists to lead
our projects development. The basic idea behind this project was to find a way to measure and
control the temperature of water entering one end of Friedrich’s A/C coil and then measure the
water’s temperature change after leaving the air conditioning coil on the other end. The initial
concept was that a pump would be needed to move the liquid through the coil and the
temperatures/pressures would be recorded. After planning, designing and brainstorming with the
group and with the sponsor, a consensus was reached in terms of the exact functionalities of our
testing apparatus. The system’s design is complex as it takes up quite some space and must meet
official requirements. All parts of the system need to be able to be readily accessible due to the
high-risk nature of the system. When planning the design, the engineering method, principals and
guidelines were used to create a finished product. Extensive analysis and calculations have been
made to finalize material selection and to satisfy customer needs.
8
To begin the development of CCATS our team employed system development and time
management tools to guide our design processes and to define a schedule for completing taskings
and project goals. Our team decided to utilize the engineering V system development tool which
outlines a chronological series of critical system development milestones. When following the
engineering V model, we begin with the first step in the upper left side of the engineering V and
work our way down the V until the system detail designs are completed. At the bottom of the V
the completed design is to be implemented and the system shall be constructed. Once the system
is built, we next move up the right side of the V by testing, refining and validating the systems
performance to ensure all requirements are fulfilled. To help keep our team on successful path to
completing the CCATS project our team also decided to utilize a Gantt Chart. The Gantt Chart
was utilized to build a calendar to track the status and progress of critical taskings completion, set
milestones and deadlines for the complete on of each the system design’s critical taskings as well
as track the amount estimated hours of work needed and hours spent to complete taskings.
Once our senior design team was approved to work the development of the Friedrich’s
calorimeter. Our team first goal was to gather up documentation resources and standardizing
literature about similar calorimeter system construction and operational standards in order to
develop a breakdown of the overall concept of operation for our project design. Copy of links to
our reference are located in attached appendixes.
4.0 SENIOR DESIGN GHANT CHART
Date Tracking Gantt Chart Calendar
9
Figure 2: Senior Design Gantt Chart
The Gantt calendar works as part of the overall Gantt tracker and is used in conjunction with
tasking lists and sub level trackers to assess and monitor the overall development of the system.
10
Figure 3: Date Tracking Gantt Chart
The Gantt chart help our team identify our teams senior design project’s key milestone
and to set deadlines for the completion of critical tasks. Key mile stone dates were met
chronologically as the team completed processing steps of the engineering V system model.
Senior Design Project Task List
11
12
Figure 4: Senior Design Task List
Our team divided the project’s tasking mostly by engineering disciplines the mechanical
aspects were headed off by Noel and the electrical aspects were led by Christopher. This task list
enabled the team to keep track of the project’s overall development status through each step of
the build process. Task were broken into stages of the systems engineering v model plus our
classes addition senior design tasking.
5.0 SYSTEMS ENGINEERING APPLICATION
The Engineering “V” system development methodology was utilized through the life of
the project and acted as a step thru guide on how to apply a system engineering solution to
Friedrich’s future coil testing potential. The Engineering “V” is broken down into seven steps
and starts with clearly identifying and understanding the problems surrounding the need for the
system and the concepts of operations to the proposed solutions. Tasking is then focused
towards building the architecture, implementing designed solution and the testing validation and
system refinement. The model loops back to verification and validation after operations and
maintenance of the system.
System Engineering V Model
Figure 5: System Engineering V Model
The Engineering “V” model outlines a sequence of key steps in the systems develop
process focused around spending time in an efficient manner. The Engineering V model was
used for this project because it calls for each step to be given time for completion and each step
helps build up the other to provide a system engineering approach solution to Friedrich’s future
coil testing capabilities.
6.0 CONCEPT OF OPERATION
Utilizing the Engineering “V” model our team focused first on identifying Fredrich's need for the
system’s development and defined our project’s definition. The cornerstone for our system was
set through Microsoft Teams meeting with our advisors and sponsor thru August 2020. In the
concept of operation meetings we collect applicable publications resources surrounding air and
water temperature and flow rate measurements and testing environments chambers and discussed
project management objectives. Our team was fortunate to have a running head start on this
project thanks to the 2019-2020 Saint Mary’s University Senior Design team. Thanks to a huge
help from our mentors, we identified the need to provide Friedrich the ability to independently
14
test the heat transfer performance of units coils. The coil calorimeter automated testing system
was beginning to instantiate.
Our team’s first proposal drafts took on a similar appearance to our predecessors' final design
and operation scheme. We wanted to use the parts on hand from the19-20 project to minimize
future project’s cost. We developed top level system designs to showcase how our team
envisioned the calorimeter would function and for our sponsor and mentors to judge and
determine if the calorimeter would be the answer to establish Friedrich’s independent coil testing
operations. Our team used block diagram sketches to illustrate how each sub sections of the
calorimeter’s would operate and how the whole system would function as a whole. Top level
flow charts help engineers share a bird's eye view of what a system takes in for inputs and what it
put outs for outputs. These diagrams help engineers share functionality details about a system or
component in an easy-to-read intuitive picture. Our team built the systems overall concept of
operations by separating each of the main system processes into separate top level flow charts.
The five sub system flow charts created for CCATS were designed for the power flow, data flow,
water flow, and air flow of the system during this first stage of development.
The first versions of flow charts created were drawn on paper in our senior design folder
and posted online in our senior design project share files. Revisions to digitally formatted charts
soon followed for editing and illustrating convenience. A preferred yet illusive tool to generate
these digital charts would have been the Microsoft Visio program. None the less our team digitized
diagram mostly thru Power Point or SolidWorks and Multisims.
Initial Concept Drawings
Initial Top Level Concepts of Operation
16
17
These initial drawing were used by the team to buildup top level concepts of operations and to
better understand how to implement the team’s solution on how to test the efficiency of
Friedrich’s evaporator and condenser coils.
Power Consumption Chart
Powering charts and matrices were used throughout our team’s systems development process.
These charts were instrumental in routing power to all the subcomponents of the calorimeter.
Similar charts were developed to implement sensor routing to the Redlion HMI modules for
temperature and pressure readings.
Power Wiring Schematic Draft
Figure 9: Power Wiring Schematic Draft
The early electrical schematic were developed in Multisims ; the team later focused on building drawings in
Solidworks electrical to accommodate custom components outside the programs library easier. Multisim schematics
offer simulation; while Solidworks electrical schematics illustrate wire and component routing that can be tied to the
Solidworks CAD drawing of the calorimeter.
Top Level Water Flow
Figure 10: Top-Level Water Flow
The top-level water flow chart illustrated above breaks down how the water in the system
is piped and how it will circulate during operations. The water will be measured in three different
ways temperature, flow rate, and pressure to accurately capture the amount of energy diffused
through the coil. The process begins inside our water reservoir. Using the force of gravity fluid is
fed into the water pump from the tank. The pump’s job is to distribute that fluid throughout the
system while the heating rod and chiller get the water to proper temperature. The water that exits
the chiller makes its way into a 3-way valve, depending on flow rate specifications, the fluid will
then split in two directions: one back to the reservoir and the other into the testing coil. From the
coil water ultimately returns to the tank and the process repeats.
7.0 REQUIREMENTs & ARCHITECTURE
After building an understanding of Friedrich’s project and getting approval of our initial
concept of operations from our sponsor and advisors we began to move forward with our project’s
development taking the critical step of gathering requirements from our sponsor to ensure the
20
system would be a viable option for Friedrich’s coil testing operations. Our main objective in this
stage was to define our sponsors finer wants and needs for testing their coils. Our team held
meeting with our sponsor lead at Friedrich’s lab and online from mid to late September 2020 to
learn and discuss requirement for their system. We used an excel spreadsheets to track the list of
verifiable system requirements. This list was vital to our project success as it gave us a benchmark
in which to grade our systems performance and design. Establishing the project requirements was
a joint effort led by our sponsor to define criteria surrounding the project’s management,
budgeting, designing and manufacturing. Defining clear tangible requirements in this early stage
of the project’s build later proved to be instrumental for validating our final prototype.
Project Requirements
Other requirements included product delivery date, parts and power consumption
limitations, project presentations, operating ranges, documentation and safety features including
an emergency off switch.
Having the requirements set clearly for us by Friedrich ensured our team was providing
our sponsor with a product they would use. Attention was given to user friendliness and our team
aimed to deliver Friedrich with a product operators could safely and easily test any variety of coil
models.
21
8.0 DETAILED DESIGN
After most of the requirements were finalized with Friedrich, our team focused our
engineering efforts towards developing a full detailed system design. Our detail design taskings
proved to be one of the more challenging and time-consuming parts of our senior design project.
During the detail design phase of our team’s taskings were aimed at mapping out how the system
would function and ultimately be built.
8.1 CCATS AUTOMATED CONTROL SYSTEM
Our team started the development of CCATS’s finer subsystems details in October – and
ended designing the full system integration in January. We managed the design phase by
breaking down the system into subsystems sections each having live documentation and progress
status on Teams. This helped us tracked of CCATS overall design progress based on the
completion of each of the subsystem’s designs. Our team held design meeting for the system
design statuses weekly during class and semimonthly during the winter break. Team meetings
online and in the lab were helpful to discuss the more intricate details pertaining to the
mechanical structure and electrical functionality of the systems designs. During our design
meetings the team would address foreseeable issues to the project development and propose
viable measures of controls to mitigate possibilities of progress and system failure. During the
winter break efforts were focused to build a Crimson developed program in charge of operating
the systems Red Lion Human Machine Interfacing (HMI).
Documentation for the Red Lion HMI programming and helpful customer support is
limited. Much of the info found on developing Crimson programs were scattered vaguely thru
Red Lion’s PLC datasheets and technical notes.
22
The development of HMI programming was needed to allow operators to actively interact
with CCATS. The programming was development to easily allow users to enter testing
parameters and log the testing data. Programming for the HMI included graphic user interface
(GUI) development, logic programming and networking.
CCATS Graph User Interface Screen View
Figure 12: CCATS Graph User Interface Screen View
The HMI has a touchscreen interface which allows operators to input controls and testing
parameters. A menu option was built to allow users to navigate smoothly from one system
configuration and monitoring.
The HMI was developed to monitor and control CCATS thru an array of inputs and
outputs. Variables for each object in the system were generated by creating data tags in crimson
software. Tags were given labels, data types and assign to inputs and outputs for each register.
CCATS Data Tag List
Figure 13: CCATS Data Tag List
The data tag list the labels and types of signals the systems uses as inputs and outputs.
This chart was fundamental to building finer detailed controls and wiring designs.
Crimson Software Development Data Tags
24
Figure 14: Crimson Software Development Data Tags
Data tags can be created and formatted in crimson to function as internal variables or
external. The input / output pins on the HMI’s modules were assign to data tags to read
temperature, pressure and water flow rates.
IEC 61131-3 control programs were created under the Control section in crimson. The
programs were designed to run the systems testing functions, control the systems water
temperature and flow rate and to safety monitor the status of the systems. The program illustrated
below functions to run a coil test for the users set duration and to turn off when the test time has
elapsed.
25
Figure 15: Testing Program Crimson Development
Trouble shooting skills are beneficial in programming with Crimson because the software
will allow you to compile and transfer an erroneous database to your system which will cause the
HMI to function undesirable. Some programming errors may cause the system to crash or reset
proper syntax was critical.
HMI Display Home Page
Figure 16: HMI Display Home Page
The Home page is the first page users will see appear on the HMI once powered up. From
here users can access the menu screen to navigate thru the system's interface.
HMI Display Test Settings
Figure 17: HMI Display Test Settings
The Test Setting page allows user to enter their testing parameters ,ID and part numbers.
Once the test settings are confirmed by the operator the system will set the water’s temperature
and flow rate to match the user’s settings.
HMI Display Test Menu
Figure 18: HMI Display Test Menu
The Test Menu displays the user’s settings and allows the user to select when to start or
stop coil testing. When testing is running the system will log the read data from sensors.
HMI Display Data Logger
Figure 19: HMI Display Data Logger
The Data Logger menu logs the values of the systems temperature flow rate and pressure
reading during testing. Graphs are generated to show the temperature difference between air and
water in going in the coil vs air and water temperatures coming out of the coil.
HMI Display System Status
Figure 20: HMI Display System Status
The System Status menu give an overall view of how the system is operating with alert
and event display to signal operator of significant changes
HMI Display Shutdown
Figure 21: HMI Display Shutdown
The Shutdown menu act to provide users with a digital Emergency kill switch. When
activated system will stop all testing functions and kill power to the heater, chiller, and pump. To
completely safe the system the manual emergency switch must be pulled.
The HMI was mounted in a control box to afford operators easy access to data and
control during all phases of testing. The systems wiring was routed from the right side thru six
holes separating power in and out from control signals in and out. The emergency switch
controls turning the system fully on and off. Access to the control box requires a flat head
screwdriver to unlatch the two locks on the upper and lower right areas of the front face.
Control Box Assembly
Figure 22: Control Box
The control box front facing door is designed to opens horizontally from right to left.
This design was suggested by end users to mitigate safety risks of door falling on them if the
door was opened vertically. Safety is top priority.
To develop wiring schematic for the power and sensors for system I/O matrixes, power
charts, and solid works electrical software were utilized. Two power inputs were needed to run
the array of system subcomponent. A 240 VAC 30Amp and 120VAC 15 Amp wall outlets were
given as our power sources. Budgeting power designs became an issue on the 120 VAC side
when too many components where required to be powered on 120VAC to remedy power
limitations the L1 line from the 240VAC power source was wired to provide a 120VAC source
32
for the blowers and pump. This allowed us to draw 120VAC power need without going over the
dedicated 120VAC line’s 15 Amps limit. This solution was also recommended by an end user.
Power Wiring Schematic
Figure 23: Power Wiring Schematic
The circuit was built in SolidWorks Electrical and show how power is routed from the
two different power outlets to energize the subcomponents throughout the system. A unique
feature of the power circuit is one leg of the 240VAC power in line was routed to provide 120
VAC to the pump, and fan blowers.
33
Figure 24: HMI I/O Matrix
The HMI has 4 I/O modules that allowed sensor readings and signal output features to be
monitored and controlled using system programming. The I/O matrix helped to generate how the
HMI I/O panel would be wired as seen below the following schematic.
HMI I/O Panel Wiring Schematic
34
Figure 25: HMI I/O Panel Wire Schematic
The I/O wiring was design separate from the power wire to elevate wiring clutter on
drawings and to help keep the wires with power being tied together with wires caring sensor
measurements signals. Each of the four I/O modules attached to the HMI provide its own unique
feature to the system. Some modules acted as only an input reader and some only as output
generators others could do both. To collect the multiple sensor measurements and control
subcomponents as desired drove the reasoning behind having four I/O modules.
Inside of Control Box
Figure 26: Inside of Control Box
This photo of the control box shows the white input sensors wiring harness (upper right)
being fed in separately from the power in and out wire bundles (lower right). The sensors’ wires
are shielded and routed away from wires carrying power to the system’s subcomponents. The
wires carrying power and signals are kept separated to mitigate any interface in measurement
readings.
36
Figure 27: CCATS Version 1 Design Testing Apparatus Breakdown
Our device can be broken into three major components. The bottom half of the device or
the area circled in red is our environmental control chamber. Here the device is in charge of
heating/cooling the fluid to begin testing. The water reservoir, the pump, the chiller, and the
heating rod work together to meet required fluid temperatures. Once we have reached the adequate
temperature, PVC piping is used to transfer our fluid from the bottom half of our testing apparatus
and into the next chamber. The chamber circled in blue is our testing chamber. The yellow
rectangular prism seen inside resembles a testing coil. Treated water is ran through this coil and
tested for efficiency. In addition to water, our device mates with Bertha (an air vacuum machine)
to suck air through our coil and help determine temperature changes. This testing chamber has
been modified to adjust to a majority of coil sizes found within the Friedrich facility. The last
37
chamber within our testing apparatus is the electrical chamber circled in green. This is the brain of
our entire device. Here the user will be able to communicate with the device through a Human
Machine Interface (HMI). One can monitor the fluid temperatures and collect data from the testing
chamber. All in all, the electrical chamber pieces the puzzle together.
Frame #7 Finite Element Analysis (FEA)
Figure 28: Frame #7 Finite Element Analysis (FEA)
Frame #8 Finite Element Analysis (FEA)
38
Figure 29: Frame #8 Finite Element Analysis (FEA)
Another component of the engineering method deals with designing. The images above
depict our seventh and eighth frame iterations. A key component of the engineering method
deals with creating and improving on past iterations. After having ran through a series of design
options, frame #8 was able to capitalize and so we ran a Finite Element Analysis (FEA) on
SolidWorks. Much of the deformation takes place towards the bottom of our frame, but our
selected material (Aluminum 6105-T5 alloy) absorbs that quite well. From the data off to the
right we can see that the areas highlighted in red experience the most deformation. It is important
to note that the highest end of the spectrum deals with a .0006 in of deformation when converted
to the appropriate units and so the frame can be deemed as successful for this application.
8.3 FRAME DESIGN
Of the most crucial steps in beginning our project was the frame design. We had to keep
in mind that we would be housing several subcomponents who each stacked weight to the overall
39
system. In addition to holding up such weight, the requirements also called for a relatively light
system because it was ideal to transport CCATS by a single individual.
First Iterations of the Frame
Figure 30: First Iterations of The Frame
From the first iterations of our frame, the understanding of what exactly we were building
was not fully there. We were aware that we needed to include several components, but we did
not understand how they worked in unison. At this point, there was no knowledge of standards
that had to be met and for all we knew, our frame had to house the components listed by the
previous senior design group. From this the first iteration was born which featured 8020
aluminum extrusion measuring 1.5in x 1.5 in. 8020 is a relative lightweight and easy-to-
manipulate aluminum alloy which was referred to us by our sponsor. Their previous projects had
incorporated this material and its satisfactory results encouraged them to continue using it. In
40
addition to this, our cart was split to house the environmental control chamber in the bottom half
and the testing chamber in the top half accompanied by the electrical control box.
As time went by, so did the frame iterations. We began to fully grasp what we were
building, and we began to familiarize ourselves with the standards that put a toll on our design.
After numerous additional supports, changing of profiles, and the relocation of key components
we reached our final frame iteration.
Final Frame Iteration
Figure 31: Final Frame Iteration
The final frame design features a 98in x 72in x 30in frame built to sustain the desired
load all while still possessing the capability to be transported from room-to-room by a single
individual. This model splits into the original three chambers and possess a new tank designation
41
which allows for gravity to work its magic through the pipe routing. The next several pictures
will show all angles of our fully finished frame.
Final Frame Isometric View
Final Frame Top View
42
8.3.1 SLIP OR TIP CALCULATIONS
One of the key requirements of this build is in reference to weight. Being able to move the cart
single handedly and transport it from room to room was key. For this reason, a relatively light
but durable frame was incorporated. Some components weighed nearly 200 lbs. themselves and
following OSHA regulations was a must. According to OSHA an individual who is carrying,
pushing, or lifting has reached maximum weight when the item they are working with weighs 50
lbs. Calculations met this criterion and they read as follows:
CCATS Free Body Diagram
=
−42.5(40) + 850 (30/2) − 1 (72/2) = 0
1 = 360.33s
The force labeled as Fc indicates the amount of forced needed to get the cart moving. A value of
42.5 lbs. falls shy of the 50 lbs. regulation and in turn meets OSHA regulations. Taking the
moment at point B indicates whether the cart will move or tip over when exerting the force
44
labeled as Fc. From this summation of forces, the value 360.33 lbs. is acquired for the value of
N1. This means that at N1, 360.33 lbs. are pushing up the cart up to tip it over but because our
carts weight sits at 850lbs, this tipping force is not strong enough and this results in a fully
transportable cart.
8.3.2 FINITE ELEMENT ANALYSIS
Once the frame was fully put together, it was time to put it to the test. SolidWorks
incorporates a finite element analysis feature on their software which allows the user to test loads
on frame designs. This feature gives access to dozens of metal types and offers a variety of
fastening and welding methods. Unfortunately, SolidWorks does not have any 8020 extrusions in
their default settings, so an extra step had to be taken for our application. The 8020 website
allows users to download SolidWorks parts for any and all the goods that they offer to their
customers. Simply type in “SolidWorks downloads” into the finder and the website allows one to
download the specific part they are looking for. Once downloaded onto the computer, it is
important to store it under the specific files where the rest of the default options are found. This
can be located through SolidWorks to find its location and the downloaded files can be moved
there through the disk of the computer. Once, the appropriate 8020 profiles have been relocated,
the frame begins to come to life. At this step, finite element analysis does the rest of the work.
Simply state where the loads will be acting on the frame and in which direction they will be
pushing/pulling. Once this has been established, SolidWorks generates the stresses on the frame.
Finite Element Analysis
Figure 36: Finite Element Analysis
The above image yields frame displacement as portrayed by SolidWorks. The bottom section of
our frame was where much of the bending action took place. This was because this section was
carrying the weight of the frame and the weight of many of the components. The image depicts
small purple arrows pointing in the downward direction that can be seen all through the bottom
section and through most of the framing that houses the water tank. These indicate the direction
in which the frame is being pulled because of the loads. Over to the right of the frame we can
make sense of whether the frame will sustain the loads. Red signifies where the most stress is
seen followed by green and ultimately into the blue section. Alongside this rainbow-colored bar
we can quantify these bending values. The bar ranges from 8.071 x 10^-3 ft (red section) to
3.281 x 10^-33 ft (blue section). This ultimately tells us that the section experiencing the most
stress is the bottom red part of the frame and it is displacing by 8.071 x 10^-3 ft. After dividing
that value by twelve to convert from feet to inches, the displacement in this area yields 6.6808 x
46
10^-4 inches. Because the displacement is so minimal, the frame passes the test and verifies that
the design does not need any adjustments.
8.4 AIR SAMPLER DESIGN
Figure 37: Air Sampler #1
An air sampler is a device that reads wet bulb and dry bulb temperatures when retracting air at a
certain flowrate. From ASHRAE 41.2, 37, and 41.6 we got an overall idea of how these air
samplers look but no specifications to construct on one. Luckily, Friedrich had built some in the
past for personal use and we ran with their idea. The results are in the image below.
Air Sampler #1 Solidworks
Figure 38: Air Sampler #1 (SolidWorks)
Our device uses two air samplers. One to measure wet bulb and dry bulb temperature
before contacting the coil and one to measure the same variables after the air has ran through the
coil. The image above illustrates the air sampler which takes measurements prior to the air
interacting with the testing coil. Our sponsor made it clear that the sampler needed to adjust to
different coil sizes and to meet that criterion we came up with the following. The main 4” - 26”
long PVC pipe seen in the overhead branches out into 6 - 1”- 17” long PVC receiving pipes. One
end of the main pipe was sealed off with a PVC cap and the other uses a 4” to 3” adapter to feed
an insulated hose into a psych box. The receiving pipes are mounted in such a way that they can
adjust to different widths established by the coil being tested. A simple unscrewing of a nut
loosens each individual pipe to allow for relocation. To connect from the main pipe to the
branching pipes, we clamped together a 1” insulated hose directly onto the mouth of the
branching pipes. The branching pipes feature 8 varying size holes facing the direction of air
travel. The dimensions of these holes were determined by the desired airflow. If our airflow was
48
below our expectations, the holes were simply sized up until our desired value was met. The
setup allowed for maximum flexibility and easy adjustment to all test coils.
The first iteration of our second air sampler came from the idea of having it mounted in
what Friedrich calls “Bertha.” Bertha is essentially a huge air vacuum that is used to measure
airflow. Inside Bertha’s airflow chamber there is sufficient space to mount such air sampler and
record temperature readings after the air has contacted the coil. Because the first iteration of the
frame was rather short in length, to meet ASHRAE standards it was a must to place this air
sampler inside Bertha. However, while designing our new frame we made sure to erase the
hassle of having such device inside of Bertha because that meant that wires were to be ran from
CCATS and into Bertha opening a possibility for air leaks. Although this idea was never
implemented, the drawings are as followed.
First Iteration Air Sampler #2
Figure 39: First Iteration - Air Sampler #2
Final Iteration Air Sampler #2
49
Figure 40: Final Iteration - Air Sampler #2
The construction of the second air sampler was straight forward. Because it did not have to
adjust to several coil sizes, its application was universal for all. We kept the main pipe 4” wide
and 26” long. We piped the receiving pipes directly into it using a threaded joint which on one
end attached to the main pipe and on the other to the 1” pipes. The same trial and error approach
was used to identify the hole sizes on the branching pipes. Again here, the 4” main pipe was
sealed on one side using a cap and the other side fed into a psych box.
8.5 HEAT EXCHANGER
Another factor required by CCATS was a method of heating water to test coil efficiency.
Because treated water is going to be pumped into the testing coil a heat exchanger is necessary to
maintain a constant water temperature running during the test. To our advantage much designing,
and brainstorming was not needed as Friedrich had already constructed such device for this
application primarily based off an inline aquarium heater. The heat exchanger consists of a 4.5”
wide and 16” long cylindrical 304 Stainless steel body which features three threaded fittings. The
inlet and outlet fittings measuring ½” and the heating rod is attached to the screw cap with a 2”
fitting. The screw cap also features an SCR which is fed into the control box and ultimately
50
monitored by the HMI. The SCR communicates back and forth between the water heater and the
HMI in parallel to the user’s instructions. For example, if the water needs to be heated at a higher
temperature, the SCR regulates the power being outputted into the water heater. In this case, it
would be drawing in more power. The equation is rather simple, more heat equals more power
drawn and less heat equals less power drawn. All this is done under the supervision of the user
and what they instruct to the SCR.
Water Heater Design
Water Heater
Figure 42: Water Heater
8.5.1 HEAT TRANSFER CALCULATIONS
When conducting the heat transfer calculations, a desired warm up time was chosen. Ideally, the
water’s ambient temperature is 65 and will raise 45 in order to be ready to test the
condensing coils. First the amount of heat required to achieve an increase of 45 was found. A
desired warm up time of 30 minutes was used to perform the heat transfer calculations to
51
determine how many Watts were needed in order to achieve the task. In the most extreme case,
the prototype will have to test an evaporating coil followed by a condensing coil. At such
extreme, the prototype will be required to heat up the water by 60 . The calculations break
down in the following manner.
Thermodynamic Cycle Simplified
Conversion Factors
• 1 W = 0.2903 BTU/hr.
= p (Eqn. 3)
= (166.74 ) (1.00 / ∗ ) (45)
= 7,503.3
• Heating rate in order to heat up in 30 minutes:
= () / () (Eqn. 4)
52
= (7,503.3 ) / (. 5 ) = 15006.6 /
• Watts needed to achieve the required change in temperature at the desired time:
1 = 0.2903 /
= 4,356.42
≈ 4,500
A sweep is the time that it takes the entire 20 gallons to pass through the water heater. For
example, a pump with the capacity of 5 gal. per minutes takes 4 mins. to cycle through the 20
gal. of water. The change in temperature per sweep was calculated in the table below. In order to
verify the calculations, one heater will be used and tested in the cycle to verify that for the four
minutes the 20 gal. increased approximately 2.17 .
Expected Change in Temperature
Table 1: Expected Change in Temperature
8.6 THERMODYNAMICS
The thermodynamics simplified cycled mentioned above illustrates how heat is added to
our system. The configuration depicts our water reservoir, followed by the water pump, who is in
charge of pushing our treated water through the system. After the pump comes the water heater.
The water heater essentially heats our water by converting electrical energy coming in from an
outlet and dissipating that energy into the heating rod found inside the cylindrical chamber of our
water heater. The contact between the fluid and the heat rod causes the fluid to increase in
53
temperature. In addition to heating the fluid, chilling it is also a must. For this reason, an explicit
version of the thermodynamics cycle was recreated.
Updated Thermodynamic Cycle
Figure 44: Updated Thermodynamics Cycle
The figure above depicts the travel path of the fluid focusing primarily on the thermodynamics of
the project. From the reservoir, the fluid reaches the pump via gravitational force and the pump
pushes the fluid through the remaining components of the cycle. The fluid first reaches the water
heater, followed by the chiller and on to the three-way valve. At this point, the user sends an
electronic signal to the ball valve via HMI telling it to reroute the water back into the reservoir or
up into the testing coil. The fluid has now been treated to a desired temperature and to avoid an
excess flow, the three-way ball valve sends unwanted fluid back into the reservoir.
8.6.1 THERMODYNAMICS CALCULATIONS
Energy Balance Equations
Pump
Qin − Qout − Wout + Win + Σm(hin − hout + ΔKE + ΔPE) = ΣEsys (Eqn. 5)
Win + Σm(hin − hout) = 0 W in = Σm (hout − hin)
Coils (Heat Exchanger)
54
Qin − Qout − Wout + Win + Σm(hin − hout + ΔKE + ΔPE) = ΣEsys (Eqn. 6)
Qin + Σm(hin − hout) = 0 Q in = Σm (hout − hin)
Reservoir @ 50 Fluid Temp
in − Qout − Wout + Win + Σm(hin − hout + ΔKE + ΔPE) = ΣEsys (Eqn. 7)
−Qout + Σm(hin − hout) = 0 Q out = Σm (hin − hout)
System
coils − Qreservoir − Wout + Win + Σm(hin − hout + ΔKE + ΔPE) = ΣEsys Qcoils − Qreservior + Win = 0
Q coils = W in + Q reservoir (Eqn. 8) Condensing Coil
Pump
in − Qout − Wout + Win + Σm(hin − hout + ΔKE + ΔPE) = ΣEsys (Eqn.
9)
Coils (Heat Exchanger)
Qin − Qout − Wout + Win + Σm(hin − hout + ΔKE + ΔPE) = ΣEsys (Eqn. 10)
−Qout + Σm(hin − hout) = 0 Q out = Σm (hin − hout)
Reservoir @ 110 Fluid Temp
Q in − Qout − Wout + Win + Σm(hin − hout + ΔKE + ΔPE) = ΣEsys (Eqn. 11)
Qin + Σm(hin − hout) = 0 Q in = Σm (hout − hin)
System
Qreservoir − Qcoils − Wout + Win + Σm(hin − hout + ΔKE + ΔPE) = ΣEsys Qreservior − Qcoils + Win = 0
Q coils = W in + Q reservoi (Eqn. 12) 9.0 WATER FLOW
Water Flow Chart
Figure 45: Waterflow Diagram
The waterflow diagram reflects the fluid path of our system. The process begins with the
water reservoir. The reservoir features an inlet which attaches to a water hose. This allows the
tank to be filled up by simply connecting the female end of the inlet to the male head of the hose.
Once water begins to fill the tank, gravitational flow will allow the water to run into the pump.
The pump then pushes the fluid through each component and back into the reservoir. At the
pump outlet we have attached a water filter. The filter allows the water to be debris-free as it
may be contaminated when exchanging from coil to coil. This prevents any malfunctions in the
subcomponents of the system. You may be asking yourself why we would place the water filter
after the pump if the coils will be the main factor in contributing to contamination. The answer is
that the force provided by gravity will not be enough to push the water in the water filter to the
inlet of the pump if we were to switch these two components up. That then raises the possibility
to damage the pump if coil debris winds up in there. To avoid such tragedy, we have asked our
sponsor that before testing any coil it is an absolute requirement to run water through it and get
56
rid of any excess bits. Next in the process comes the water heater followed by the chiller.
Depending on the desired temperature these two will be working together to achieve such value.
The sponsor has made it clear that 95% of the time the chiller will be up and running. This means
that the water heater will have to oscillate in order to reach a constant fluid temperature. Because
the heating rod works in conjunction with an SCR, electrical signals will be dictating when the
heater needs to draw more or less power. The fluid then leaves the heater and comes to the
chiller. Here the fluid does the exact opposite of what it normally does when inside the heater.
The chiller features a coaxial heat exchanger which removes the heat from the fluid and in turn
cools the fluid down. The chiller and the heater will be working in conjunction to ensure the fluid
remains at a constant temperature. After the fluid exists the chiller, it reaches the three-way ball
valve. The valve works like a PVC T-elbow in such a way that it allows the flow to split from
one direction and into two. This is much necessary in our system as it allows for the regulation of
water flow that goes into our test coil. If too much pressure has built up, the three-way valve
opens and sends excess fluid back into the reservoir. If the fluid returns to the reservoir the cycle
closes there. If the fluid does not return it goes into the next component, the Coriolis meter. The
Coriolis meter measures the water flow running through the piping and then attaches to the coil
inlet. The fluid runs through the coil and then returns the fluid back to the reservoir to fully
complete the cycle.
Assumptions of the cycle and function of each component are as followed.
• Steady flow process
• Working Fluid: Water
Reservoir (20 gallons):
• no significant heat loss
• Used to prevent debris from coil from getting into pump
• Assuming ΔT is negligible
• No significant pressure losses
• Planned to use to activate bypass
Testing Coil:
8.7 FLUID ANALYSIS
Fluid calculations were performed with a few initial assumptions about the fluid flow. It
is assumed that the free surface of the velocity is at atmospheric pressure. This is possible
because the water reservoir tank is not sealed off to the environment which would create a
pressure differential. The second assumption is that the velocity at the free surface is zero. With a
58
large enough water reservoir and small enough piping diameter, this holds true. Velocities were
calculated assuming different volume flowrates that are desired at different points throughout the
system. The fluid flow for this application is turbulent and can be verified with the Reynolds
numbers at various points throughout the system. In order to calculate an equivalent head loss
value, the Darcy friction factor equation must be utilized. The relative roughness for plastic
materials is low compared to metal alloys. This in turn contributes to lower friction coefficients
throughout the piping. Head loss is constituted of two main types: major and minor head loss.
Major head loss is a result of friction within the pipe. The rougher the material and the longer the
piping, the higher the value for major head loss. Minor head loss is due to various components
within the piping system which will disturb the velocity profile of the fluid. This will include 90°
bends, ball valves, tees, filters, etc. The equations found below, in addition to properties of water
such as density, viscosity, and specific gravity were used to calculate desired fluid dynamic
values.
γ +
V12
Head loss: hL = hL major + hL minor (Eqn. 14)
Major head loss due to friction in pipes: hL major = f v2
2g (
l
D ) (Eqn. 15)
Minor head loss due to piping components: hL minor = KL v2
2g (Eqn. 16)
Volume flowrate: Q = A (Eqn.
18)
59
8Q (Eqn. 22)
Using the above equations and other known information, we can calculate key values of
interest at various points throughout the piping system which are of high importance to us. These
areas will tell us the behavior of the fluid flow and pressures at specified points. In turn, this
information can help us determine proper material and component selection. We are specifically
interested in calculating the values at four distinct locations in our piping system: The free
surface of the water reservoir, the pump inlet, the pump outlet, and the test coil inlet. The free
surface of the water reservoir acts as our reference point because we know that most of the
values here should be zero since there is no pipe flow existent at this point. We were also
interested in the pressure before and after the pump. The pressure after our pump should be the
highest pressure throughout the entire system. Knowing this value and the pressure at the pump
inlet can help us to determine the amount of work needed by the pump to achieve the desired
pressure differential. The pressure at our test coil inlet is to be verified with the experimental
value and we need to ensure that it is held constant as much as possible across the coil. If this
parameter holds true, then our data captured will be verified.
Fluid Calculations
Psi(abs) ft/s ft ft3/s ft n/a
60
Pump Inlet 2.00 6.95 0 0.01 3.37 23668.48
Pump Outlet 1.67 30.08 0.67 0.05 23.66 113484.29
Coil Inlet 2.78 6.02 3.08 0.01 4.75 22698.22 Table 2: Fluid Calculations
8.7 MATERIAL AND COMPONENT SELECTION
The following sections outline in further detail the thought process and justification for material
and component selection in our system. All these decisions were made off a combination of
extensive research, suggestions from one another including the sponsor, faculty staff and
calculations through calculations which proved to solidify such selections. We know there is
always room for improvement in selecting materials as time does do its part to wear things out,
but we believe that our cart will be durable, reliable, and long-lasting based upon the selections
we have made hopefully serving Friedrich well for years to come.
8.8.1 PIPING
To transport fluid from component to component, our system will feature a custom
CPVC pipe routing. There were several requirements that led us to crossing out materials from
the list and ultimately leading us to the most suitable in the bunch. One of the biggest factors that
was kept in mind was selecting a material that would sustain temperatures as low as 55 and as
high as 110 all while meeting the pressure requirements. Another requirement included
selecting a diameter size easily adaptable to the inlets and outlets of all waterflow components.
Because maintenance on components would be required in the future, the piping also had to be
designed with such parameters in mind.
PVC vs CPVC Schedule
Max Pressure 600 psi @ 72°F 850 psi @ 72°F
61
Table 3: PVC vs CPVC Schedule
½” Chlorinated polyvinyl chloride pipe (CPVC) piping was our final selection. This
material is relatively light in weight, offers great corrosion resistance, and is an over-the-counter
purchase. This material also offers a wide range of connectors and adapters to join, merge and
couple pieces together. PVC itself is used for a wide range of applications while CPVC is most
recognized for plumbing applications regarding cold and hot water. CPVC also features a higher
temperature resistance due to its Schedule 80 feature which looks at pipe thickness. To address
the issue regarding maintenance, ball valves were incorporated to allow individual components
to be removed from the system.
PVC/ CPVC Ball Valve
Figure 46: PVC/CPVC Ball Valve
To connect piping where they meet with connectors, primer and PVC cement was used.
This establishes a solid seal and erases the possibility of any water leaks. Individual components
offer female fittings while our piping offers male fittings. To attach these together, we wrapped a
generous amount of pipe joint tape to the male end and screwed it into the female end.
62
8.8.2 COIL CONNECTORS
Finding a connection which reduced from ½” CPVC to 3/8” was quite tedious. Our initial
intention was to use clamps and rubber hosing until we found out that the coil inlet sizes vary.
From there we went to our second option which was proposed by the previous senior design
group working on this project. Their suggestion was EZ Connect ZF2 fittings. These fitting
attached to the ends of the coil inlet and the CPVC outlet and popped into place easily. Once
again here the problem was that we were performing test on a range of inlet sizes. On one of our
Home Depot runs we spent over an hour and a half looking through copper and brass fitting until
we finally came to consensus. From this visit, we purchased a ½” to 3/8” reducer which attached
to the end of the CPVC pipe. We then attached the reducer to 3/8” hosing and again to 3/8”
reducer. This second reducer could then be attached to 3 other fittings that we purchased in order
to meet the full range of coil sizes. To avoid leakage, hose clamps can be found at the ends
where the reducers meet hoses. A rather conventional approach but one which performs excellent
for such application.
8.8.3 WATER PUMP
To determine an adequate pump for this application an experiment was ran by the previous
senior design group using the Coriolis meter.
Mass Flow Rate Experiment
Figure 47: Mass Flow Rate Experiment
The experiment consisted in measuring out approximately fifteen pounds of water in a 5-
gal. bucket. Then a visual mark was created on the exterior of the bucket at the free surface of
the water. Over the course of ten trials, a water hose was ran through a condensing coil with 3/8
in. diameter headers, seen in Figure 22. A 3/8 in. diameter was significant here because it was
the size of the largest coil we would be testing. The coil had the least amount of resistance,
which meant it would yield the highest amount of flow needed for the application. Once the fluid
low was in a steady state at a specified pressure, filling the bucket and start a timer would begin.
When the bucket reached the mark, the time was noted, the bucket was emptied, and the test was
ran again. Using conversions, a flowrate was found in terms of gallons per minute (GPM) and
used to calculate the average and maximum flowrate. The results showed an average flowrate of
4.618 GPM and a maximum flowrate of 4.75 GPM as shown in Table 4. The results were then
verified with the Coriolis meter. The results were a pump with a capacity of 5 GPM at a
specified pressure head which would be under 5ft.
64
(lbm/min)
1 11.0 24.11 0.62 37.35 4.48
2 11.0 23.51 0.64 38.31 4.59
3 11.2 22.92 0.65 39.29 4.71
4 11.0 22.74 0.66 39.60 4.75
5 11.0 23.23 0.65 38.77 4.65
6 11.2 23.15 0.65 38.90 4.65
7 11.0 23.17 0.65 38.87 4.66
8 10.9 24.03 0.62 37.48 4.49
9 10.8 23.1 0.65 38.99 4.68
10 11.8 24.07 0.62 37.42 4.49
Table 4: Mass Flow Rate Data
When selecting the actual pump, we guided ourselves on recommendations from our
sponsor. Several names were tossed back and forth but we ultimately went with a pump brand
which Friedrich currently uses in their San Antonio installations, Walrus. Because the data used
to calculate a 5 GPM pump featured a 5 ft pressure head, this pump would not work for our
newly designed frame. Our frame extended a little over 6ft and such pump would fail in this
application. After going through the Walrus GPD Series Circulator Pump catalog, we capitalized
on the GPD25-10SFC 115V. The specs are shown below.
Walrus GPD25-10SF Pump
Figure 48: Walrus GPD25-10SFC Pump
Walrus offered a great deal of pumps which featured a max head of 6 ft and below.
Figure 23 shows that our pump offers a max head of 24 ft with a 20 GPM capacity. The gap
between 6ft and 24ft is substantial but after talks with a Walrus representative, this was their
recommended alternative.
8.8.4 CORIOLIS METER
The purpose of the Coriolis meter is to measure fluid flowrate at a specific point in time
within our piping. We do not have a specified flowrate we must achieve; this is up to our own
discretion. The Coriolis meter will ensure we have achieved steady state conditions before
beginning to collect data. It is why this instrument is placed before the testing coil in the
66
waterflow diagram in Figure 20. Once steady state conditions have been met, the change in
temperature readings will be much more significant.
Endress + Hauser Promass Coriolis Flow Meter
Figure 49: Endress + Hauser Promass 83E Coriolis flowmeter
We will be using an Endress + Hauser (E+H) Promass 83E Coriolis flowmeter as shown
in Figure 29. These instruments have the capability to measure both gases and liquids using
minimal process points with high precision. E+H has a reputation for providing reliable, cost-
effective solutions across a range of industries. The Promass 83E has a rated process pressure of
1450 psi and a temperature rating of 302. Both parameters do not present issues for our
application. It has been mounted onto the frame using custom-made brackets and in a vertical
upright position where fluid flow travels in the upward direction as recommended by the
operating manual. The inlet and outlet of the device have dictated the piping size that will be
present in CCATS, ½” piping. Because such instrument was provided by the sponsor, our focus
included understanding the instrument and how it would interact with other components rather
than avoiding the hassle of selecting a device that would perform such action.
67
8.8.4 RESERVOIR/WATER TANK
With fluid needing to travel throughout the system, a reservoir is needed to house the
fluid in motion and when not in motion. Selecting a reservoir considers the amount of fluid in the
system, the heat transfer of the fluid, and the rate at which the fluid will be traveling. It was
determined that the total charge of a Friedrich air conditioning unit contains approximately 1
gallon of refrigerant. When divided amongst two coils in a unit, each coil holds half a gallon of
refrigerant. The amount of fluid in the piping needed to satisfy 10 ft after rounding up to allow
sufficient cushion in case of any miscalculations. After the selection of the pump, we were able
to view the maximum flow rate of 20 GPM as another given in our problem statement.
The initial solution was to incorporate a 7-gallon ventilated tank. The tank would be
compact enough to fit into a corner of the cart and be cost-effective. There were two significant
issues with this proposal. The first had to do with the amount of time in which water would
completely cycle through the system. Because the reservoir had a 7-gallon capacity and the
pump had a maximum flow rate of 20 GPM, the total mass of water in our system would cycle
through in under a few seconds. Having such window to establish steady state conditions and
capture a reliable data set is a difficult job. Additionally, as we manipulate the temperature of the
water, we would be overworking the water chiller and heating rod to continuously maintain a
constant temperature. If we only had a 7-gallon tank, the water temperature could rise very
quickly and begin to boil which could cause cavitation within the system or it would melt the
piping material. The same holds true for the opposite condition if the water temperature gets too
cold. The water could freeze over and create difficulty in the flow. From the fluid mechanics
standpoint, the reservoir needs to be large enough to ensure that the free surface of the tank can
be assumed to have a zero velocity. With the 7-gallon tank and pipe size of ½”, this may not be
68
proven true. The solution was to increase the capacity of the tank to 20 gallons. This would allow
fluid to always be present in the tank when filled completely. The free surface zero-velocity
assumption would remain true as well as having an easier approach to maintain constant fluid
temperatures. The 20-gallon tank was the finalized decision and was purchased without any pre-
installed fittings. In addition to meeting the capacity requirement, the tank also sustains fluid
temperature requirements to further ensure our purchase. Custom installed fittings were made
based upon the piping which directly connected to the tank. To drain and refill the tank, the tank
features an access hole on its top surface as well as a plug on the bottom face which allows for
fluid drainage. We also utilized wedges to provide a certain degree of tilt on the tank ensuring
the fluid can be drained from the tank when necessary.
20 Gallon Water Reservoir
8.8.5 THREE-WAY ACTUATED BALL VALVE
To effectively compare and calculate coil efficiency, we must ensure that each coil,
regardless of size, is receiving the same inlet mass flow rate. This will ensure minimal error
when determining the amount of heat lost through the testing coil. To ensure such phenomenon,
a three-way actuated ball valve will be incorporated somewhere along the lines. From Figure 20
it is evident that the valve sits between the Coriolis, the reservoir and the chiller. After the fluid
69
exits the chiller, it has already been treated to a desired temperature. The valve then allows the
fluid to travel any of three directions: back to the reservoir, into the Coriolis, or split into both.
Because we want to establish a constant mass flow rate, any excess flow will be redirected into
the reservoir while the rest of the fluid works its way to the Coriolis and ultimately into the test
coil. This is key in avoiding back pressure on the pump.
The valve is controlled electronically by the user through an actuator. The user
communicates with the HMI where signals are sent over to the actuator telling it to open or close
accordingly. If the system is exerting an excess flowrate, the HMI will be programmed to allow
the user to open the valve with the press of a button. This action will tell the actuator to open the
ball valve and allow excess flow to be redirected into the reservoir.
The perfect selection for this application is a DeeLat 3/8” valve. The valve has a power
supply of 12V or 24V and the actuator’s control way is from 0-10 VDC /10- 20mA.
Deelat Three Way Ball Valve
70
8.8.6 WATER CHILLER
Coil efficiency requires the testing of both condensing and evaporating coils. To knock
out half of the equation, a water chiller will be incorporated when testing condensing coils.
Within this half of the equation, testing conditions require fluid temperatures of 55. Keep in
mind that we will be working with ambient water temperature of about 70. That means that our
colling device must be able to drop at least 20 in temperature. Researched from the previous
group made it clear that finding such a device was everything far from easy. The researched
proved that aquarium chillers only dissipated so much heat, industrial chillers required concise
71
and strict operating environments, and purchasing oversees products from China was a risky
move.
Friedrich’s expertise in air conditioning seamlessly transferred over into the creation of a
water chiller. The final product involved the use of a water-refrigerant heat exchanger to achieve
the desired temperature of 50. In fact, the solution was convenient in the sense that it did not
require much research because it would be an adaptation of a Friedrich air conditioning unit,
seen in Figure 28. The vision was to eliminate the air-refrigerant heat exchange process that
normally occurs in an air conditioner by replacing the evaporating coil with the coaxial heat
exchanger from Figure 27.
A coaxial heat exchanger is essentially a tube within a tube where two different fluids are
passed through in opposite directions. In one direction, we will pump our fluid ideally at room
temperature through the inner tube while the outer tube has refrigerant R-134a running through
it. When the fluids come into contact with one another, the heat transfer will occur by means of
conduction. The R-134a refrigerant will force the water to extract heat into the atmosphere and
drop in temperature. Friedrich provided a S-frame unit to incorporate into our calorimeter. The
S-framed model features a coaxial heat exchanger with a 1-ton capacity which converts to 12000
BTU/h. A smaller sized