In a refrigeration system, which process occurs within the evaporator?

In a refrigeration system, the primary process that occurs within the evaporator is evaporation. The evaporator is designed to absorb heat from the environment or the space being cooled, which typically involves a refrigerant that is in a low-pressure liquid state entering the evaporator. As the refrigerant passes through the evaporator coils, it absorbs heat from the surrounding air or liquid, causing it to change from a liquid to a vapor. This heat absorption removes heat from the space being cooled, effectively lowering the temperature in that area.

The terms associated with the other processes are critical in the overall refrigeration cycle, but they occur in different components of the system. For instance, condensation occurs in the condenser, where the vapor refrigerant releases heat and changes back into a liquid state. Compression takes place in the compressor, where the refrigerant vapor is compressed, increasing its pressure and temperature before it enters the condenser. Expansion happens in the expansion valve or device, where the refrigerant undergoes a pressure drop, allowing it to enter the evaporator at a lower pressure and cooler temperature, ready to absorb heat once again. Thus, the evaporator's function is specifically tied to the evaporation process, where heat is absorbed, leading to cooling.