What does a properly functioning expansion valve prevent at the end of the evaporator?

A properly functioning expansion valve is crucial in a refrigeration system, particularly at the end of the evaporator. Its primary role is to regulate the flow of refrigerant into the evaporator, ensuring that the refrigerant is at the correct temperature and pressure to absorb heat effectively.

When the expansion valve operates as intended, it allows only vapor to exit the evaporator. If liquid refrigerant were to accumulate at the end of the evaporator, it could lead to inefficiencies in the cooling process and potentially damage the compressor, which expects only vapor.

Thus, preventing liquid refrigerant from leaving the evaporator is essential for maintaining the system's efficiency and protecting the components from potential harm. Maintaining the proper phase of refrigerant at this stage helps ensure optimal heat absorption and overall system performance.