Refrigeration is defined as “ the branch of science that deal with the process of reducing and maintaining the temperature of confined space or material below the temperature of surrounding” the system maintain at lower temperature is known as refrigerated system and equipment used to obtain this is known as refrigerator. The cooling effect produced by this equipment is the refrigerating effect.
2. PRINCIPLE OF REFRIGERATION
According to Clausius’s statement of second law of thermodynamics ,heat does not flow from low temperature region to high temperature region without help of external energy. Thus ,in order to transfer heat from low temperature to high temperature ,work must be supplied to refrigerator, which produces cooling effect.such cooling may be obtain by one of the following principle. 1. By chemical mean ,in which chemical reaction is carried out to absorb the heat for its completion. The heat required for reaction taken from the substance to be cooled. 2. By bringing the substance to be directly or indirectly in contact with some cooling medium such as chilled water or ice. 3. By using mechanical and heat energy to operate heat pump.
* METHOD OF REFRIGERATION
Refrigerating effect can be produced by using following methods.— 1) Ice refrigeration. 2) Refrigeration by expansion of air. 3) Refrigeration by throttling of air 4) Steam jet refrigeration 5) Vapour compression cycle 6) Non convention method of refrigeration a) Vortex tube refrigeration b) Pulse tube refrigeration c) Solar refrigeration
1) REVERSED CARNOT CYCLE 2) AIR REFRIGERATION CYCLE a) BELL COLEMAN AIR REFRIGERATION CYCLE 3) VAPOUR COMPRESSION CYCLE
1. REVERSED CARNOT CYCLE
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