What is the function of a thermal expansion valve?

The function of a thermal expansion valve is to regulate the flow of refrigerant into the evaporator. This component plays a critical role in the refrigeration cycle by controlling the amount of refrigerant that enters the evaporator coil based on the cooling demand. As the temperature of the refrigerant decreases, the valve opens and allows more refrigerant to flow into the evaporator. This regulation helps maintain an optimal pressure and temperature within the evaporator, ensuring efficient heat transfer.

In contrast, the other choices define functions that are performed by different components in the cooling system. For instance, converting refrigerant from a gas to a liquid is the role of the condenser. Compressing refrigerant for efficient cooling is a function of the compressor. Lastly, absorbing heat from indoor air is primarily done by the evaporator coil itself. Understanding the specific role of each component is essential for grasping the overall operation of HVAC systems.