In this cycle, the compressor is energized and begins to circulate refrigerant at the suction side. The refrigerant begins as a vapor, is compressed, and exits the compressor as a superheated vapor. This superheated vapor then moves to enter the condenser. Inside the condenser, the superheated vapor begins to cool by extracting the heat to the air surrounding the condenser coil, (at a constant temperature and pressure) and condenses into a liquid before exiting. The liquid refrigerant then moves through the tubing to the metering device or expansion valve. At the metering device, the liquid is restricted causing a sudden decrease in pressure which then begins to evaporate. At this point the refrigerant is at a half liquid and half vapor state, producing the low temperature, low pressure refrigeration process. The cold liquid and vapor moves through the evaporator and is completely vaporized, in turn, removing heat from the air surrounding the evaporator coil. The vapor exits the evaporator and returns to the compressor, completing the refrigeration cycle. This is a basic representation of the whole process using air flow as the medium being cooled, used to give you an idea of how refrigerant works within a cooling system. There are many variations of this system, but all work on the same principals.
