What is the function of a thermal expansion valve (TXV)?

The function of a thermal expansion valve (TXV) is integral to the refrigeration cycle, particularly in controlling the flow of refrigerant into the evaporator. The TXV regulates the amount of refrigerant that enters the evaporator based on the cooling load and ensures that the refrigerant exits the evaporator at the correct superheat level. Superheat refers to the temperature of the refrigerant vapor as it leaves the evaporator, which is above its boiling point at a given pressure.

By maintaining proper superheat, the TXV ensures that only vapor enters the compressor, preventing liquid refrigerant from reaching the compressor, which could potentially cause damage. Proper control of superheat also enhances the efficiency of the system, ensuring that the evaporator operates effectively to absorb heat from the space being cooled.

In contrast, other options suggest functions that are not aligned with the TXV's role in the refrigeration cycle. For instance, lowering refrigerant pressure before it enters the compressor does not occur with a TXV; this role is fulfilled by a different component, specifically the evaporator and the expansion device. Circulating refrigerant through the system is primarily the responsibility of the compressor, not the TXV. Lastly, while cooling the compressor components can be a result