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CHAPTER, , 1, 1.1, , Fundamental of Refrigeration, , INTRODUCTION TO REFRIGERATION AND AIR, , CONDITIONING SYSTEM, Refrigeration is the process of removing heat from the system under controlled conditions, in such a way that the temperature of the system is lower from surrounding., OR, Science of producing and maintaining the temperature of system below the surrounding, atmosphere is known as refrigeration., Those elements which lower the system temperature collectively are known as, , refrigeration system., Refrigeration effect can be obtained by following three methods, , Melting of solid, Sublimation of solid, , Evaporation of liquids, Commonly we use the third method., , APPLICATION OF REFRIGERATION, Various applications are as follows:, , In ice making, I n transportation of food, I n industrial air conditioning, I n air conditioner, I n chemical industries, I n medical and surgical kits, I n various food products, I n oil refining and synthetie rubber industries, I n manufacturing and treatment of metals, , Building, , construction.

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2I Refrigeration and Air Conditioning, ELEMENTS OF REFRIGERATION SYSTEM, Basic Elements, , of Refrigeration system are as follows, , (a) Heat sink through which, , air is cooled., , (b) Medium through which heat is extracted from heat sink., , (d) Refrigerant, (d) Medium of reducing pressure and temperature., , AIR CONDITIONING SYSTEM, Air conditioning is defined as - "It is an assembly of various components in which we, , control the thermodynamic property on air in such away that it produces comfortable air., Various thermodynamic properties are, , Temperature, , Humidity, Molecular action, , Atmospheric purity, Elements of Air conditioning System, The elements of the system are as follows, , Fan, Filter, , Refrigeration plant, Heater, , Humidification and dehumidification equipments, , Control system., .5, , UNIT OF REFRIGERATION, , Practically refrigeration is measured in "Tonne of Refrigeration (TR)"., "A tonne of refrigeration is defined a s the amount of refrigeration effect, uniform melting of one tonne (100 kg) of ice at 0°C in 24 hours.", , We know that, Latent Heat of Ice = 335 kJ/kg, , 1 TR =1000 x 335 kJ in 24 hours, 1 TR =, , 1000 x 335, , 24x60, , 232-6 kJ/min, , 1 TR =232.6 kJ/min, Practically 1 TR = 210 kJ/ min, , 3 . 5 kW, = 3 5, , kJ/sec, , produced by the

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Fundamental of Refrigeration I 3, , 1.6 REFRIGERATION EFFECT, It is defined as the amount of cooling produced by a system. This cooling is obtained at the, expense of same form of energy., , OR, Amount of heat extracted in a given time from a refrigeration system., Refrigeration Effect = COP x work done, , 1.7 CO-EFFICIENT OF PERFORMANCE OF REFRIGERATOR, Performance of refrigerator is measured in terms of co-efficient of performance., Co-efficient of performance of Refrigerator is defined as, "The ratio of heat extracted in, the refrigerator to the work done on the refrigerant.", Let, , R,, , Net, , =, , Refrigerating Effect, , W Work done, , Then, , COP, , Net refrigerating Effect, Work Done, , COP, , R, W, , This is theoretical co-efficient of performance. Value of COP is always greater than one., , Relative COP=, , 1.8, , Actual COP, , Theoretical cOP, , DIFFERENCE BETWEEN COP AND EFFICIENCY, , Co-efficient of performance is the reciprocal of the Efficiency., To understand the difference between COP and efficiency first we draw the diagram of, Heat engine, Heat pump and, , refrigerator, , Heat, , Heat, , source, , SOurce, , Heat, , T, , Source, , Q= Q,+ WR, (E, , WE, , R WR, , p, , Wp, , WE O-a, Heat, sink, , T, Heat Engine, , Heat, , sink, , T, Refrigerator, Fig. 1.1, , Heat, sink, Heat Pump

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4, , Refrigeration and Air Conditioning, Work done, , EHeat supplied, (COP),, (COP)R, , Refrigerating effect, , Refrigeration vork, =, , (COP)R Q, Produced Effect, , (COP) Work done, (COP),p, , =, , (COP)p Q -1, Relation between (COP), and (COP)R, , (COP)p, , -&1, , (COP)Re -1, (COP)p, , 2-1, (COP)p =(COP)R, , 1.9, , +1, +1, , METHOD OF REFRIGERATION, , Methods of refrigeration are as follows:, , ) Ice refrigeration, (i) Air refrigeration, (1ii) Vapour Compression refrigeration, , iv) Vapour absorption refrigeration, , (v) Special refrigeration systemn, , Cascade, , refrigeration system, , Mixed refrigeration system, , Vertex, , Tube refrigeration system, , Thermo-electric refrigeration system, Steam Jet refrigeration system.