NATE Air Conditioning and Heat Pumps Practice Exam

Boiling of the refrigerant occurs in the evaporator, which is a key component of the refrigeration cycle. In the evaporator, low-pressure refrigerant enters as a liquid and absorbs heat from the surrounding environment. As it absorbs heat, the refrigerant's temperature rises, causing it to change from a liquid state to a gaseous state through the process of boiling. This phase change is crucial because it allows the system to absorb heat from the space being cooled, effectively lowering the temperature.

The evaporator's ability to boil the refrigerant is essential for the cooling process, as it contributes to the overall efficiency and performance of the air conditioning system. The other components, while critical to the system's function, do not facilitate the boiling process. The compressor compresses the refrigerant gas, the condenser removes heat and condenses the refrigerant back into a liquid, and the metering device regulates the flow and pressure of the refrigerant entering the evaporator.