Which device controls the flow rate of refrigerant into the evaporator?

Which device controls the flow rate of refrigerant into the evaporator?

• A. Compressor
• B. Condenser
• C. Metering device
• D. Evaporator

Answer: (C)

The metering device is responsible for regulating how much refrigerant enters the evaporator. It throttles the high-pressure liquid exiting the condenser, dropping its pressure and temperature so the refrigerant can begin to boil and absorb heat inside the evaporator. This flow control sets the evaporator pressure and the amount of refrigerant that can vaporize, helping maintain the desired superheat and preventing both flooding and starvation of the evaporator. The compressor moves refrigerant through the system by increasing pressure, but it does not control how much refrigerant enters the evaporator. The condenser’s job is to reject heat and condense vapor into liquid, not to govern flow into the evaporator. The evaporator is where heat absorption happens, not where flow is throttled.

The metering device is responsible for regulating how much refrigerant enters the evaporator. It throttles the high-pressure liquid exiting the condenser, dropping its pressure and temperature so the refrigerant can begin to boil and absorb heat inside the evaporator. This flow control sets the evaporator pressure and the amount of refrigerant that can vaporize, helping maintain the desired superheat and preventing both flooding and starvation of the evaporator.

The compressor moves refrigerant through the system by increasing pressure, but it does not control how much refrigerant enters the evaporator. The condenser’s job is to reject heat and condense vapor into liquid, not to govern flow into the evaporator. The evaporator is where heat absorption happens, not where flow is throttled.