period one
Absorption Refrigeration Cycle
notes
reject heat
condenser
compressor
expansion device
energy in
evaporator
$%
absorb heat
Figure 5
In the vapor-compression refrigeration cycle, refrigerant enters the evaporator in the form of a cool, low-pressure mixture of liquid and vapor ($). Heat is transferred from the relatively warm air or water to the refrigerant, causing the liquid refrigerant to boil. The resulting vapor (%) is then pumped from the evaporator by the compressor, which increases the pressure and temperature of the refrigerant vapor.
The hot, high-pressure refrigerant vapor (&) leaving the compressor enters the condenser where heat is transferred to ambient air or water at a lower temperature. Inside the condenser, the refrigerant vapor condenses into a liquid. This liquid refrigerant (') then flows to the expansion device, which creates a pressure drop that reduces the pressure of the refrigerant to that of the evaporator. At this low pressure, a small portion of the refrigerant boils (or flashes), cooling the remaining liquid refrigerant to the desired evaporator temperature. The cool mixture of liquid and vapor refrigerant ($) travels to the evaporator to repeat the cycle.
The vapor-compression refrigeration cycle is discussed in detail in the
Refrigeration Cycle clinic.