“Refrigeration” is science of producing & maintaining the temperature below that of surrounding.
Its Process of removing the heat from cold body & rejecting it into hot body, in order to keep cold body at lower temperature, than its surrounding.
Refrigerator is a machine by means of which cold can be produced.
Refrigerant is a working substance (liquid or gas) used in refrigerator to absorb heat from cold body and reject it into hot body.
Refrigeration effect is the amount of heat removed from the cold body by refrigeration.
Unit of Refrigeration system is Ton which is denoted by “TR”.
Coefficient of performance (COP) is a ratio of heat extracted in refrigerator to the work done on refrigerant.
COP= Q/W ,
Q=amount of heat extracted in refrigerator
Lets focus on some Properties of refrigerant , An ideal refrigerant should have the following properties…
1.Low boiling point
2.High critical temperature
3.High latent heat of vaporization
4.low specific heat of liquid
5.low specific volume of vapour
6.Non corrosive to metal
7.Non flammable & Non explosive
- Natural refrigeration system
- Mechanical refrigeration system
- Air refrigeration
- Vapour refrigeration –
- vapour compression refrigeration system – The vapour compression refrigeration system is nowadays used for all purpose refrigeration, here a suitable refrigerant i.e freon, NH3CO2 etc. is used in the system The refrigerant used does not leave the system, but its circulated throughout system alternately condensing & evaporating. Main elements : 1.Compressor (hermetically sealed), 2.Condenser, 3. Throttle valve, 4. Evaporator etc.
- vapour absorption refrigeration system – The idea of vapour absorption refrigeration system is to avoid compression of refrigerant i.e. compressor is not used in this system Main elements : 1.Generator, 2.Rectifier, 3.Condenser, 4.Throttle valve, 5.Evaporator, 6.Absorber, 7.Pump, 8.Heat exchanger etc.