Which device regulates pressure and flow of refrigerant to the evaporator?

• A. A/C Compressor
• B. Thermal Expansion Valve
• C. Evaporator
• D. Receiver-Drier

Answer: (B)

Metering refrigerant flow into the evaporator is done by the thermal expansion valve, which regulates both the pressure drop and the amount of liquid that enters the evaporator. It sits between the high-pressure liquid line and the evaporator inlet and responds to conditions at the evaporator (like pressure and superheat) to throttle the refrigerant. By doing this, it prevents flooding the evaporator with too much liquid or starving it with too little, ensuring efficient heat absorption and proper system operation. The compressor creates the high-side pressure, the receiver-drier stores and filters, and the evaporator is the heat-exchanging component; none of those regulate the flow into the evaporator like the TXV does.