What is the purpose of a TXV (Thermostatic Expansion Valve) in an HVAC system?

The purpose of a TXV, or Thermostatic Expansion Valve, in an HVAC system is to control the flow of refrigerant based on the temperature of the evaporator. The TXV is designed to modulate the amount of refrigerant that enters the evaporator coil, which is essential to maintaining the desired cooling effect. By adjusting the refrigerant flow precisely in response to the temperature conditions in the evaporator, the TXV ensures that the evaporator can effectively absorb heat from the indoor air, allowing the system to cool efficiently and maintain comfort levels.

This capability is crucial because if too much refrigerant enters the evaporator, it can lead to flooding and inefficiency, while too little refrigerant can result in insufficient cooling. The TXV uses a sensing bulb with a gas charge that reacts to the temperature of the evaporator, thereby regulating refrigerant flow to optimize the system’s performance.

Other options relate to different functions within an HVAC system, such as pressure regulation, temperature monitoring, and air circulation, but none addresses the specific role of the TXV in controlling refrigerant flow based on evaporator temperature.