What happens to the refrigerant during the expansion process in a vapor-compression refrigeration cycle?

During the expansion process in a vapor-compression refrigeration cycle, the refrigerant undergoes a significant change in both pressure and temperature. When the refrigerant exits the expansion device, such as a thermal expansion valve or capillary tube, it experiences a drop in pressure. This pressure reduction causes the refrigerant to also cool down.

As the pressure declines, the refrigerant experiences a phase change, transitioning from a high-pressure liquid state to a low-pressure mixture of liquid and vapor. This combination of reduced pressure and lower temperature allows the refrigerant to absorb heat from its surroundings in the evaporator, enabling the refrigeration cycle to effectively provide cooling.

This process is crucial to the function of the refrigeration cycle, where the refrigerant must be in a low-energy state to absorb heat effectively from the area to be cooled.