What is the primary purpose of an expansion valve in a refrigeration system?

The primary purpose of an expansion valve in a refrigeration system is to reduce the pressure of the liquid refrigerant. This reduction in pressure allows the refrigerant to expand and change from a high-pressure liquid to a low-pressure vapor as it enters the evaporator. This transition is crucial because it lowers the refrigerant’s temperature, enabling it to absorb heat from the surrounding environment or space that needs to be cooled.

By creating a pressure drop, the expansion valve effectively controls the flow of refrigerant into the evaporator and ensures that the system operates efficiently. It plays a vital role in maintaining the desired cooling effect by regulating how much refrigerant enters the evaporator based on the cooling demand, optimizing system performance and efficiency.

In summary, the correct answer highlights the expansion valve's critical function in managing the refrigerant pressure within the system, leading to effective cooling operations.