The device that provides the pressure drop that lowers the boiling point of the refrigerant in a refrigerant circuit is the __________.

The device that provides the pressure drop that lowers the boiling point of the refrigerant in a refrigerant circuit is the __________.

• A. Capillary tube
• B. Condenser
• C. Expansion device
• D. Compressor

Answer: (C)

Lowering the refrigerant’s pressure is done by the expansion device. By throttling the high‑pressure liquid, it drops the pressure as the refrigerant enters the evaporator. At this lower pressure, the saturation (boiling) temperature falls below the evaporator temperature, so the liquid starts to vaporize by absorbing heat from the space, providing cooling. The condenser and compressor aren’t responsible for this pressure drop—the compressor raises pressure and temperature, and the condenser rejects heat at high pressure. A capillary tube is a simple type of expansion device, but the general term that covers this throttling function is expansion device.

Lowering the refrigerant’s pressure is done by the expansion device. By throttling the high‑pressure liquid, it drops the pressure as the refrigerant enters the evaporator. At this lower pressure, the saturation (boiling) temperature falls below the evaporator temperature, so the liquid starts to vaporize by absorbing heat from the space, providing cooling. The condenser and compressor aren’t responsible for this pressure drop—the compressor raises pressure and temperature, and the condenser rejects heat at high pressure. A capillary tube is a simple type of expansion device, but the general term that covers this throttling function is expansion device.