There are four basic parts in a mechanical refrigeration system, The compressor pumps refrigerant vapor. The condenser releases heat from the refrigerant, similar to a vehicle’s radiator releasing heat from the cooling system. The refrigerant control releases vapor refrigerant when it is needed. Finally the evaporator is the area that absorbs heat.
In the system, liquid refrigerant under high pressure flows from liquid receiver to pressure reducing valve (expansion valve) and into evaporator. Here pressure is greatly reduced. Liquid boils and absorbs heat from evaporator. Now a vapor refrigerant, flows back to compressor and is compressed to high pressure. Its temperature is greatly increased. In the condenser, heat is transferred to the surrounding air and the refrigerant cools, becoming liquid again. It flows back into the liquid receiver and the cooling cycle is repeated.