The Vapor Compression Cycle

Hot Region

1

2

3

Compressor

W 1-2

Expansion valve

EVAPORATOR

CONDENSER

4

q4-1

Source Cold Region

q2-3

Ideal refrigeration systems follow the theoretical Reversed Carnot Cycle process. In practical problems in the compression and expansion of a gas and vapor mixture present practical problems in the compressor and expander. Therefore in practical refrigeration compression usually take place in the superheated field and a throttling process is substituted for the isentropic expansion.  

 

 

 

 

The cycle:

 

1-2       Isentropic compression of the vapor, from the evaporating to the condensing                  pressures                        

 

2 -3      Condensation of the high pressure vapor during which heat is transferred to the high temperature region.

 

3 -4      Adiabatic throttling of the condensed vapor from condensing to the evaporating             pressure.

 

4 -1      Evaporating of the low pressure liquid during which heat is absorbed from the    low temperature source.