Subcooling of the refrigerant occurs in which component of the refrigeration system?

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

Answer: (A)

Subcooling is the cooling of the refrigerant liquid below its condensation temperature while it is still a liquid. This happens in the condenser, where the high‑pressure refrigerant releases heat to the surrounding air or water and becomes a liquid; as it continues to reject heat, its temperature can drop below the saturated temperature at that pressure, creating subcooled liquid.

Why this is important: having subcooled liquid before the metering device ensures the refrigerant enters as a single phase (all liquid), which minimizes flash gas, improves metering accuracy, and boosts system efficiency.

The evaporator is where the refrigerant absorbs heat and boils into a vapor, so subcooling does not occur there. The compressor raises the temperature and pressure of the refrigerant gas, not subcool it. The metering device throttles the liquid, but subcooling should already have occurred upstream to ensure smooth, single‑phase flow.