Which type of expansion valve adjusts the flow of refrigerant based on cooling demands?

The thermostatic expansion valve (TXV) is designed to regulate the flow of refrigerant based on the cooling demands of the system. It achieves this through a mechanism that responds to the temperature of the refrigerant exiting the evaporator. As the temperature increases, indicating a higher heat load or demand for cooling, the TXV opens more to allow a greater flow of refrigerant. Conversely, when the demand decreases, the valve closes to restrict the refrigerant flow. This precise modulation allows for efficient operation and optimal cooling, preventing issues like flooding the evaporator or starving it of refrigerant.

In contrast, a capillary tube provides a constant flow of refrigerant and does not respond to variations in cooling load, making it less responsive to system dynamics. An electronic expansion valve can also adjust flow based on electronic signals and sensors, offering precise control but requiring additional electronic components. A fixed orifice allows a constant flow rate, which cannot adjust to varying cooling demands, making it suitable only in specific applications where the load remains relatively stable.