Which device meters the flow of refrigerant into the evaporator by regulating the pressure difference between the high-pressure side and the low-pressure side?

Which device meters the flow of refrigerant into the evaporator by regulating the pressure difference between the high-pressure side and the low-pressure side?

• A. Expansion device
• B. Float valve
• C. Condenser
• D. Evaporator

Answer: (A)

The device that meters refrigerant into the evaporator by creating and regulating a pressure drop from the high-pressure side (out of the condenser) to the low-pressure side (into the evaporator) is the expansion device. It throttles the flow, so only a controlled amount of liquid refrigerant enters the evaporator, reducing its pressure and temperature enough for it to boil and absorb heat from the surroundings. This metering maintains the proper evaporator pressure and prevents flooding or starving it. Condenser is a heat exchanger where high-pressure gas or vapor releases heat and condenses; it doesn’t regulate flow into the evaporator. The evaporator itself is where heat absorption occurs and doesn’t act as a regulator in this sense. A float valve uses liquid-level sensing to control liquid entering the evaporator, not the pressure difference between high- and low-pressure sides, so it isn’t the device described.

The device that meters refrigerant into the evaporator by creating and regulating a pressure drop from the high-pressure side (out of the condenser) to the low-pressure side (into the evaporator) is the expansion device. It throttles the flow, so only a controlled amount of liquid refrigerant enters the evaporator, reducing its pressure and temperature enough for it to boil and absorb heat from the surroundings. This metering maintains the proper evaporator pressure and prevents flooding or starving it.

Condenser is a heat exchanger where high-pressure gas or vapor releases heat and condenses; it doesn’t regulate flow into the evaporator. The evaporator itself is where heat absorption occurs and doesn’t act as a regulator in this sense. A float valve uses liquid-level sensing to control liquid entering the evaporator, not the pressure difference between high- and low-pressure sides, so it isn’t the device described.