What is the primary function of a thermostatic expansion valve in an HVAC system?

The primary function of a thermostatic expansion valve (TXV) in an HVAC system is to control the flow of refrigerant based on cooling demand. The TXV operates by sensing the temperature and pressure of the refrigerant exiting the evaporator coil. It modulates the flow of refrigerant into the evaporator, ensuring that just the right amount is delivered to maintain efficiency and comfort levels.

When the cooling demand rises, the TXV opens more to allow additional refrigerant to flow into the evaporator. Conversely, when the cooling demand decreases, the valve closes to restrict the flow of refrigerant. This dynamic adjustment maintains optimal pressure and temperature conditions within the HVAC system, enhancing performance while also improving energy efficiency.

Other options, while relevant to HVAC systems, do not accurately describe the TXV’s core function. For instance, measuring the temperature of refrigerant pertains more to sensing components, increasing refrigerant pressure is typically a function of a compressor, and maintaining indoor humidity levels is primarily managed through dehumidifiers and air handling units.