SEMINAR ON “VAPOUR COMPRESSION REFRIGERATION” GUIDED BY:- PREPARED BY:- Mr. Devendra Bhandari Ujjwal Nautiyal B.Tech(ME) II sem (38)

Refrigeration  Vapour Compression Refrigeration VV apour Compression Refrigeration

 Refrigeration is a process of removal of heat from a substance at a temperature lower than the surrounding with the aid of external work.  In a refrigeration system, the rate at which the heat is absorbed in a cycle from the interior space to be cooled is called Refrigerating Effect. Refrigeration

* In a refrigerator, a medium called Refrigerant continuously extracts the heat from the refrigerator which is to be kept cool at temperatures less than the atmosphere & finally rejects to it. * Refrigerant acts as a heat exchange medium. * e.g.- Ammonia, Freon, Methyl Chloride, Carbon dioxide, Isobutane.

Unit of Refrigeration & Ice making Capacity The capacity of a refrigeration system is expressed in tons of refrigeration which is the unit of refrigeration. A ton of refrigeration is the quantity of heat absorbed in order to form one ton of ice in 24 hours when the initial temperature of water is 0°c. 1 Ton of Refrigeration = 210 kJ/min = 3.5kW Ice making capacity is the capacity of the refrigerating system to make ice beginning from water to solid. S.I. unit of ice making capacity is kg/hr.

Coefficient of Performance  The coefficient of performance(briefly written as C.O.P.) is the ratio of desired effect to the work input. Mathematically, (C.O.P.) refrigerator = Desired effect = Q 2____ Work Input Q 1 -Q 2

T 1 =T surr Source T 1 T 2 <T surr Sink T 2 R Work Input,W=Q 1 -Q 2 Heat Absorbed, Q 2 Heat Rejected, Q 1  Refrigerator is a reversed heat engine.  It extracts Q 2 amount of heat from sink & releases Q 1 amount of heat to source.  Input—Work(Q 1 -Q 2 )  Output– Heat Refrigerator

PARTS OF REFRIGERATOR Parts of Refrigerat or Evaporato r Compress or Condense r Expansio n Valve

9 Parts of Refrigerator Refrigeration

Types of Refrigeration System Refrigeration System Vapour Compression Refrigeration System Vapour Absorption Refrigeration System

11 Type of Refrigeration Vapour Compression Refrigeration Refrigeration Refrigeration cycle Condenser Evaporator High Pressure Side Low Pressure Side Compressor Expansion Device

12 Type of Refrigeration Vapour Compression Refrigeration /Refrigeration Refrigeration cycle Low pressure liquid refrigerant in evaporator absorbs heat and changes to a gas Condenser Evaporator High Pressure Side Low Pressure Side Compressor Expansion Device

13 Type of Refrigeration Vapour Compression Refrigeration Refrigeration Refrigeration cycle The superheated vapour enters the compressor where its pressure is raised Condenser Evaporator High Pressure Side Low Pressure Side Compressor Expansion Device

14 Type of Refrigeration Vapour Compression Refrigeration Refrigeration Refrigeration cycle The high pressure superheated gas is cooled in several stages in the condenser Condenser Evaporator High Pressure Side Low Pressure Side Compressor Expansion Device

15 Type of Refrigeration Vapour Compression Refrigeration Refrigeration Refrigeration cycle Liquid passes through expansion device, which reduces its pressure and controls the flow into the evaporator Condenser Evaporator High Pressure Side Low Pressure Side Compressor Expansion Device

Advantages  Very mature technology.  It has very less running cost.  It has smaller size for the given capacity of refrigeration.  It can be employed over a large range of temperatures.  The C.O.P. is very high. Disadvantages  Many systems still use HCFC refrigerants, which contribute to depletion of ozone layer.  Initial cost is high.  The prevention of leakage of refrigerant is the major problem in vapour compression refrigeration. 16

17 Seminar Seminar on on “Vapour Compression Refrigeration” THANK YOU FOR YOUR ATTENTION