1 refrigeration technology wu wei-dong chapter 1 introduction to refrigeration

1

Refrigeration Technology

wu wei-dong

Chapter 1 Introduction to refrigeration

2


wu wei-dong

Chapter1 ： Introduction to refrigeration

Definition and Scope of Refrigeration

Main Applications of Refrigeration

History of Refrigeration in the world

Academic Organizations and Journals of Refrigeration in the world

References

Chapter 1 :Introduction to refrigeration

3


wu wei-dong

• Definition and Scope of Refrigeration Literally, the word “refrigerate” is to make or keep cool or cold; to

preserve (food, biologicals, etc) by keeping cold and freezing, as in Webster’s New World Dictionary.

According to ASRE (American Society of Refrigeration Engineering), refrigeration is defined as the science of providing and maintaining temperatures below that of surroundings.

Refrigeration may also be defined as the artificial withdrawal of heat, producing in a substance or within a space a temperature lower than that which would exist under the natural influence of surroundings.


4


wu wei-dong

• 1. Refrigeration and Heat Pump The places, where surroundings are at temperatures lower

than the required condition, have to be heated up. The similar machinery as refrigerator which performs the

heating process is called a heat pump. The main difference between the refrigeration system and heat pump system can be physically conceived of from the fact that in the former there is pumping of heat out of the system into the surrounding as against pumping of a heat from surrounding into the system in the latter case.

Thus a refrigeration system can be used as a heat pump, just by reversing the direction of operation as shown in Fig.1-2.


5


wu wei-dong


6


wu wei-dong

• 2. Refrigeration and Air Conditioning

The definition of comfort air conditioning is “the process of treating air to control simultaneously its temperature, humidity, cleanliness, and distribution to meet the comfort requirements of the occupants of the conditioned space”

Refrigeration can offer cooling, dehumidifying, and also heating (by heat pump) for air conditioning. Refrigeration has also many other applications other than air conditioning, as shown in Fig.1-3.


7


wu wei-dong

• 3. Refrigeration and Cryogenics On principle, refrigeration is concerned with all the

temperature regions below the surroundings, down to absolute zero degree 0 K.

Nevertheless there is some agreement that cryogenics is concerned with temperatures below about 120 K, approximately, which is a little above the normal boiling point of liquefied natural gas. The concept was adopted at the 13 rd Congress of the International Institute of Refrigeration.


8


wu wei-dong

• 1. Comfort air conditioning Comfort air conditioning applies not only in domestic,

office, and commercial building, but also in automobile, train, ship, and airplane. Comfort air conditioning is one of the largest applications of refrigeration.

There are mainly three kinds of air conditioners (AC) for domestic, office, and commercial building: window air conditioner, split system air conditioner and central air conditioning system. The last one is also called “Chilled-water and Cooling-tower AC Unit” .


Main Applications of Refrigeration

9


wu wei-dong

• 2. Industrial air conditioning The term industrial air conditioning will refer here to

controlling air conditions to meet the requirements of the industrial processes.

Such as the constant temperature and constant humidity rooms for precision machinery, printing and photographic process, textile plants, and also low temperature, for example -40, environmental laboratories.

The air temperature in computer rooms need to be maintained the range of 20 to 23, and the relative humidity between 30-45 % .


10


wu wei-dong

• 3. Food and pharmaceutical cold preservation and Cold Chain

(1)Cold Storage Many pharmaceuticals are heat sensitive, hence it is

necessary to store them in cold state. Most meats, fish, fruit, and vegetables are perishable, and

refrigeration is an appealing preservation process of foods because it is one of the few ways that preserve the original properties of foodstuffs.

The purpose of food refrigeration is to extend their storage life and to maintain their freshness.


11


wu wei-dong

(2)Rapid freezing Rapid freezing is a good approach for food cooling, by

which higher quality can be reached. Rapid freezing prevents undesirable large ice crystals

from forming throughout the food product. Slow freezing creates large ice crystals. During thawing, they damage the cells and dissolve emulsions.

This causes meat to “drip” (lose) juiciness. Emulsions such as mayonnaise or cream will separate and

appear curdled.


12


wu wei-dong

（ 3 ） Several measures of rapid freezing 1) Air freezing 2) Plate Freezing 3) Liquid immersion or spraying Freezing 4) Cryogenic Freezing

（ 4 ）“ Cold chain” Cold Chain is a temperature-controlled supply chain for perishable

goods such as foods and pharmaceuticals. In the cold chain, storage and distribution activities must maintain a

given temperature range to prevent product spoilage. Specific temperature tolerances vary, depending on the actual items

being shipped.


13


wu wei-dong

• 4. Industry and construction processes(1)Food processing For example in the brewing industry, the refrigeration

controls the fermentation reaction and preserves the intermediate and final products.

A key process in the production of alcohol is fermentation, an exothermic reaction.

For producing a large-type beer, fermentation should proceed at temperature between 8 and 12 , which is maintained by refrigeration .


14


wu wei-dong

(2)Chemical and Process industries Some important functions served by refrigeration in

chemical and process industries are removal of reaction ①heat, condensation of gases, or separation of gases, ②

solidification of liquid, and maintenance of a low ③ ④temperature of stored liquid so that the pressure will not be excessive.


15


wu wei-dong

(3)Construction Process Refrigeration is widely applied in construction processes, such as in

large dam and underground. There are very large volume concretes in such construction. During the concrete-pouring and curing portion of construction, the

temperature control is necessary to prevent the cracking. Several cooling measures are used, like piping refrigerated water

through tubes into the wet concrete. This is to remove the heat generated by the chemical reactions that

solidify the concrete.


16


wu wei-dong

• 5. Air liquefaction and separation Air consists primarily of 78% nitrogen and 21% oxygen,

and also some rare gases, such as Ar, Ne, He. Liquid air is used commercially for freezing other

substances and especially as an intermediate step in the production of nitrogen, oxygen, and argon and the other inert gases.

The air liquefaction and air separation approach is based on the application of refrigeration.

Firstly, air is pressurized in a compressor, and after going through heat-exchangers it is expanded in the expansion machine or on a throttle valve.

As a result the temperature falls down and the air turns into a liquid.


17


wu wei-dong

• 6. Cryobiology and cryomedicine（ 1 ） Cryobiology It is a new area of science. It can be regarded as a branch of biology dealing with the

properties of biological cells at low temperatures, and also as that of refrigeration dealing with the use of refrigeration technology in the biology and medicine.

Cryobiology has mainly two applications: Cryosurgery and Cryopreservation.

（ 2 ） Cryosurgery (also called cryotherapy) It is the use of extreme cold to destroy abnormal tissue.


http://www.cancer.gov/Common/PopUps/popDefinition.aspx?term=cryotherapy&version=Patient&language=English

http://www.cancer.gov/Common/PopUps/popDefinition.aspx?term=tissue&version=Patient&language=English

18


wu wei-dong

（ 3 ） Cryopreservation In the other hand, cryobiology

has found its unique application in the long-term storage of living cells and tissues at low temperatures, which is called cryopreservation.


（ 4 ） Freeze-drying Freeze-drying, or lyophilization, is another method of preservation by refrigeration. Firstly the materials are cooled to low temperatures; the water in the substance is almost completely frozen. Then the water is sublimated from the solid state directly into the vapor phase during drying process. The freeze dried stuff can be stored at normal temperature in vacuum state.

19


wu wei-dong

• 7. Rocket propellant and cryoelectronics(1)Rocket propellant Propellant is the chemical mixture burned to produce

thrust in rockets and consists of a fuel and an oxidizer. A fuel is a substance which burns when combined with

oxygen producing gas for propulsion. An oxidizer is an agent that releases oxygen for

combination with a fuel. The ratio of oxidizer to fuel is called the mixture ratio. Propellants are classified according to their state - liquid,

solid, or hybrid.


20


wu wei-dong

(2)Cryoelectronics Low temperature electronics is focusing on the research

and development of electrical components, circuits, and systems suitable for applications in the aerospace environment and in deep space exploration missions.

Research is being conducted on devices and systems for reliable use down to cryogenic temperatures.


21


wu wei-dong

• 8. Superconductivity and low temperature physics

(1)Superconductivity Superconductivity is the vanishing of all electrical

resistance in certain substances. Superfluidity occurs in liquid helium and leads to the

tendency of liquid helium to flow over the sides of any container it is placed in without being stopped by friction or gravity.


22


wu wei-dong

(2) Superfluidity When liquid helium is cooled to a critical temperature of

2.17 K (called its “lambda point” ), a remarkable discontinuity in heat capacity occurs, the liquid density drops, and a fraction of the liquid becomes zero viscosity "superfluid".

The superfluid component has zero viscosity, zero entropy, and infinite thermal conductivity.

(It is thus impossible to set up a temperature gradient in a superfluid, much as it is impossible to set up a voltage difference in a superconductor) Superfluidity arises from the fraction of helium atoms which has condensed to the lowest possible energy.


http://hyperphysics.phy-astr.gsu.edu/hbase/lhel.html#c4%23c4

http://hyperphysics.phy-astr.gsu.edu/hbase/lhel.html#c3%23c3

23


wu wei-dong

• 9. Summary The main applications of refrigeration and their temperature regions are

summarized in Fig. 1-18.


24


wu wei-dong

• Refrigeration Chronology BC 1000 The Chinese cut and stored ice from the winter for

use in the summer Egyptians and Indians made ice on cold nights by setting

water out in earthenware pots AD 1787: Martinus van Marum liquefied ammonia, by

compression 1793: Lowitz obtained -50 by a mixture of snow and

calcium chloride


History of Refrigeration in the world

25


wu wei-dong

1803: T. Moore of Maryland received US patent for refrigerator. First patent issued in US on refrigeration

1823: J. Leslie constructed a vacuum/absorption freezing apparatus in England

1850: A. Twining proposed carbon dioxide as a refrigerant in British Patent 13167 of 1850.

1855: First commercial ice making plant using vapor compression refrigeration constructed in Cleveland, Ohio by Alexander Twining.

1876-77: F. Windhausen built the first industrial water vapor refrigerating machines

1886: F. Windhausen constructed a carbon dioxide operational refrigerating compressor

1892: First air conditioned house was constructed in U.S. San Lorenzo, CA by M. Dillenber

1894: H. Lorenz introduced the polytropic cycle


26


wu wei-dong

1900: W. Johnson invented the "humidistat" 1904: American Society of Refrigerating Engineers was founded 1905: Modern type Automatic Expansion Valve was patented by

Albert Marshall (US Patent 785265) 1907: W. Carrier patented “dew point control” system for precisely

controlling humidity in a room. 1908: First International Congress of Refrigeration was hold in Paris 1927 First refrigerator to see widespread use was the General Electric

"Monitor-Top" refrigerator. 1931: Dupont produced commercial quantities of R-12, trademarked

as Freon 1935: Freeze-drying equipment was developed by E.W. Flosdorff

and S. Mudd (U.S.) 1936: Albert Henne synthesized refrigerant R-134a


27


wu wei-dong

1940: Absorption refrigerating machine using lithium bromide: water was studies by Servel and Carrier

1949: Thermoelectric (Peltier effect ) domestic refrigerator was developed

1950: Commercial development of heat pumps began in U.S. There were 2000 unites made in 1954, 76,000 in 1963, 300,000 in1976.

1953: Two associations, the Refrigeration Equipment Manufacturers Association (REMA) and the Air-Conditioning and Refrigerating Machinery Association (ACRMA), united to become the Air-Conditioning and Refrigeration Institute (ARI)

1958: Screw compressors used industrially for refrigeration. 1958: In December, members of ASRE and ASHAE voted to merge

into the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).


28


wu wei-dong

1959: W.E. Gifford and his graduated student H.O. McMahon invented a new cycle for miniature gas refrigerators called G-M refrigerator

1964: The International Society of Cryobiology (“Society for Cryobiology”) was founded

1964: W.E. Gifford and his graduated student R.C. Longsworth invented the pulse tube refrigerator

1968-72: Refrigerant R-22 becomes standard refrigerant for unitary air conditioners and heat pumps

1972: ARI and ASHRAE combine forces for the first cosponsored International Air-Conditioning, Heating, & Refrigeration Exposition

1974: F. S. Rowland and M. J. Molina published the findings: they suspected that the chlorine released by halogenated hydrocarbons was adversely affecting the ozone layer. They won the Nobel Chemistry Prize in 1995.

1987: The Montreal Protocol on Substances that Deplete the Ozone Layer was negotiated and signed on September 16, 1987 by 24 countries and by the European Economic Community. The Protocol called for the Parties to phase down the use of CFCs, halons and other man-made ODCs


29


wu wei-dong

1990: London Amendment of Montreal Protocol:Parties to Montreal Protocol agreed in London to amendments that eliminate CFC use and production by the year 2000.

1992: Copenhagen Amendment: Montreal Protocol revised to advance CFC phaseout to end of 1995, with HCFCs to be phased out in steps by 2030.

1997: Climate Summit hold in Kyoto, Japan, in December 1997; The Kyoto protocol agreed to greenhouse gas cuts

2004: July 15-19, the 44th Annual Meeting of the Society for Cryobiology (CRYO2004) held in Beijing, China.

2007: December 3-14, the United Nations climate Change Conference held in Bali, Indonesia culminated in the adoption of the “Bali roadmap”.


30


wu wei-dong

• (1)International Institute of Refrigeration (IIR)

• (2) American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE)

• (3) Air-Conditioning and Refrigeration Institute (ARI)

• (4) Air conditioning and Refrigeration European Association (AREA)


Academic Organizations and Journals of Refrigeration in the world

31


wu wei-dong

• Journals relative to refrigeration in the world


32


wu wei-dong

• 1. Chinese Association of Refrigeration (CAR)• 2. China Refrigeration and Air-Conditioning

Industry Association (CRAA)


Academic Organizations and Journals of Refrigeration in China

33


wu wei-dong

Chinese journals relative to refrigeration


34


wu wei-dong

1. Gosney M.W., Principles of Refrigeration, Cambridge University Press, 1982

2. ASHRAE, Handbook, Fundamentals Volume, American Society of Heating, Refrigerating, and Air-conditioning Engineers, Atlanta, USA,2005

3. Hua Z.Z., Li Y.F., Liu B.L., Food Cold Storage and Freezing, Machinery Press, Beijing, China, 1999

4. Hua Z.Z., Ren H.S., Cryo-biomedical Techniques, Science Press, Beijing, China, 1994

5. Hua Z.Z., Freeze- Drying Technology, Science Press, Beijing, China, 2006

6. Bailey C.A., Advanced Cryogenics, Plenum Press, London, UK, 1971


References

35


wu wei-dong

7. Air Conditioning and Refrigeration Chronology --Significant dates pertaining to Air Conditioning and Refrigeration, revised May 4, 2006, Assembled by Bernard Nagengast for ASHRAE. Additions by Gerald Groff, Wolf Eberhard Kraus and International Institute of Refrigeration., ASHRAE, 2006

8. International Institute of Refrigeration, A brief history of refrigeration (www.iifiir.org)

9. Arkharov A., Marfenina I., and Mikulin Ye., Theory and Design of Cryogenic Systems, MIR publishers, Moscow,USSR,1981

10. Information Department, China Refrigeration and Air-Conditioning Industry Association, The survey of Chinese refrigeration and air conditioning industry in 2006, Refrigeration and Air-Conditioning, 7(3),1-4(9), 2007

11. Wang X.Ch., Thoughts on development of ground-source heat pump systems, Chinese Heating ventilation and air-conditioning, 37(3),38-43,2007


1 refrigeration technology wu wei-dong chapter 1 introduction to refrigeration

Documents

refrigeration system

journals of refrigeration

heat pump system

heat pumpthe places

artificial withdrawal

comfort requirements

temperatures lower

temperature lower