Expansion Valves for Car Air Conditioning Systems

The expansion valve for car A/C has a few different roles:

• It controls the drop in pressure in the A/C system needed to evaporate the refrigerant and generate cold
• It controls the flow rate of the fluid in the evaporator
• It controls the evaporator output temperature (superheating)

The expansion valve is located downstream of the receiver drier in the A/C loop.

The expansion valve receives the refrigerant fluid in an already-filtered, 100% liquid state. It then reduces the refrigerant fluid pressure before it enters the evaporator.

This pressure drop cools the fluid, which is then sprayed into the evaporator. The expansion valve for car A/C is always attached to the evaporator.