What effect does improper TXV operation have on an evaporator?

The function of a thermostatic expansion valve (TXV) in a refrigeration system is to regulate the flow of refrigerant into the evaporator based on the cooling demand and the saturation temperature of the refrigerant. When the TXV operates improperly, it can either flood the evaporator with too much refrigerant or cause it to starve due to insufficient refrigerant flow.

Flooding occurs when the TXV allows too much refrigerant into the evaporator, which can lead to poor heat exchange because the coil can become overloaded. As a result, not all of the refrigerant evaporates, which can lead to liquid refrigerant returning to the compressor, risking potential damage or inefficiency in the system. On the other hand, starving occurs when the TXV does not allow enough refrigerant to enter the evaporator, resulting in insufficient cooling and reduced efficiency as the heat exchange process is compromised.

This malfunctioning ability of the TXV directly affects the operational performance of the evaporator, making "flooding or starving" the correct response in this context.