What happens to the refrigerant in the evaporator unit?

In the evaporator unit of a refrigeration system, the primary function is to absorb heat from the environment, which is typically the area being cooled or refrigerated. As the refrigerant enters the evaporator in its liquid state, it absorbs heat from the air or water surrounding it. This heat absorption causes the refrigerant to change from a liquid to a gas, in a process called evaporation.

This is crucial for the refrigeration cycle, as the evaporation of the refrigerant removes heat from the connected environment, thereby lowering the temperature of that space. The refrigerant converts its state from liquid to gas as it absorbs heat, which is why stating that it absorbs heat and evaporates accurately describes the function of the refrigerant in the evaporator unit.

The other processes described in the other options involve different system components or stages. For example, the refrigerant compressing and heating up occurs in the compressor, while condensing and liquefying occurs in the condenser, after the refrigerant leaves the evaporator. By understanding the specific actions occurring in the evaporator, it becomes clear why the correct answer revolves around heat absorption and evaporation.