What is the function of the expansion valve in a refrigeration cycle?

The function of the expansion valve in a refrigeration cycle is to regulate the flow of refrigerant into the evaporator. This component plays a critical role in controlling the amount of refrigerant that enters the evaporator, which in turn affects the refrigeration cycle's efficiency and performance.

By managing the refrigerant flow, the expansion valve ensures that the evaporator has the right amount of refrigerant to evaporate and absorb heat from the surroundings, thereby cooling the location or medium being refrigerated. If too much refrigerant flows in, it can overwhelm the evaporator, leading to inefficiency and potential flooding of the evaporator coil. Conversely, if too little refrigerant enters, it can lead to insufficient cooling and reduced performance.

In contrast, the other options describe functions that do not align with the role of the expansion valve. The expansion valve does not absorb heat from the environment; that is primarily the role of the evaporator itself. It does not compress the refrigerant gas, as that function is serving by the compressor in the system. Additionally, while the expansion valve can influence the temperature of the refrigerant, its main task is specifically to regulate the flow into the evaporator rather than directly cooling the refrigerant itself.