Under what conditions will the temperature of the evaporator outlet be constant in a system using a TEV?

The temperature of the evaporator outlet will remain constant in a system using a thermal expansion valve (TEV) when the system loads stay fairly constant. This is due to the functionality of the TEV, which regulates the flow of refrigerant into the evaporator based on the temperature and pressure conditions at the evaporator outlet. When loads are steady, the TEV can effectively balance the refrigerant flow to maintain consistent temperatures, ensuring that the evaporator operates efficiently and reliably.

In contrast, if outdoor temperatures fluctuate significantly, the associated variations in system pressures could lead to changes in the evaporator outlet temperature. Similarly, during high system loads, the increased demand for cooling could cause the evaporator to operate less efficiently, leading to temperature variations. An oversized evaporator may not allow for proper control of the refrigerant flow, contributing to instability in the outlet temperature due to the mismatch between refrigerant flow and the cooling load.