In a refrigeration system, the expansion valve is one of the four major components of the refrigeration system: the compressor, condenser, throttle valve (expansion valve), and evaporator.
The expansion valve achieves cooling by throttling medium-temperature, high-pressure liquid refrigerant into low-temperature, low-pressure wet vapor.
Its main function is to regulate the refrigerant flow rate to adapt to changes in the cooling load:
1) Throttling: After passing through the expansion valve's orifice, the high-temperature, high-pressure liquid refrigerant is throttled and converted into a low-temperature, low-pressure, mist-like liquid refrigerant, creating conditions for refrigerant evaporation.
2) Controlling the Refrigerant Flow: Liquid refrigerant entering the evaporator evaporates from liquid to vapor, absorbing heat and lowering the temperature. The expansion valve controls the refrigerant flow rate to ensure that the evaporator outlet is completely filled with vapor. If the flow rate is too high, liquid refrigerant may enter the compressor and cause liquid hammer. If the flow rate is too low, premature evaporation may occur, resulting in insufficient cooling.