What happens to the refrigerant pressure at the evaporator outlet when an automatic expansion valve is functioning correctly?

When an automatic expansion valve is functioning correctly, the refrigerant pressure at the evaporator outlet remains constant. This is due to the design and operation of the automatic expansion valve, which is specifically meant to maintain a set pressure within the evaporator.

In systems using an automatic expansion valve, the valve automatically adjusts its opening based on the pressure in the evaporator. As the refrigerant absorbs heat and evaporates into a gas, the valve senses the pressure and modifies the refrigerant flow to ensure that the evaporator operates efficiently without significant fluctuations in pressure. Consequently, this consistent pressure allows the evaporator to work effectively, ensuring that the refrigerant can absorb the right amount of heat as it transforms from liquid to vapor, thereby optimizing the cooling cycle of the system.

This constant pressure condition is beneficial for maintaining the performance and efficiency of the refrigeration cycle, as it helps to prevent issues related to overloading or underloading the evaporator.