What is the purpose of a TXV (Thermal Expansion Valve) in HVAC?

The purpose of a Thermal Expansion Valve (TXV) in HVAC systems is to regulate refrigerant flow based on the temperature of the evaporator. The TXV adjusts the amount of refrigerant entering the evaporator coil, allowing it to match the cooling demand of the system.

As the evaporator cools, the temperature of the refrigerant changes, and the TXV senses these variations. By dynamically managing the flow of refrigerant, the TXV ensures that the evaporator can efficiently absorb heat from the indoor space, ultimately leading to optimal cooling performance. This regulation helps maintain the correct pressure within the evaporator, enhancing system efficiency and comfort.

Other options focus on different functions that do not pertain specifically to the operational role of a TXV. For example, increasing pressure in the refrigerant cycle is a function of the compressor in the HVAC system. Controlling indoor air quality generally involves filtration and ventilation aspects rather than refrigerant flow. Distributing air evenly throughout a room is primarily the concern of ductwork and airflow design rather than the function of a TXV.