The metering or expansion valve controls?

The metering or expansion valve primarily controls flow in a refrigeration or air conditioning system. Its main function is to regulate the amount of refrigerant that enters the evaporator, which is critical for maintaining the effectiveness of the cooling process. By adjusting the flow rate of the refrigerant, the valve helps to ensure that the system operates efficiently and that the temperature of the refrigerant is suitable for the heat exchange process in the evaporator.

While temperature, pressure, and velocity are important factors in the overall functioning of a refrigeration system, the metering or expansion valve specifically focuses on the flow of refrigerant. It achieves this by creating a pressure drop that allows the refrigerant to expand and change from a liquid into a gas, which is essential for absorbing heat from the area being cooled. Therefore, the control of flow by the metering or expansion valve is crucial for optimal system performance and temperature maintenance.