Subcooling is defined as which of the following?

Subcooling is defined as which of the following?

• A. The difference between evaporator suction-line temperature and the saturated vapor temperature at the low-side pressure.
• B. The difference between ambient temperature and condenser liquid temperature.
• C. The difference between condenser liquid temperature and the saturated liquid temperature at the high-side pressure.
• D. The sum of condenser liquid temperature and saturated liquid temperature.

Answer: (C)

Subcooling is the cooling of the condenser liquid below its saturation temperature at the high-side pressure. In practical terms, it’s the difference between the condenser liquid temperature and the saturated liquid temperature at the high-side. Keeping the liquid subcooled ensures it reaches the metering device as a fully condensed liquid, which reduces flash gas, improves compressor efficiency, and helps control the refrigeration system. The other descriptions mix in concepts that aren’t subcooling: the difference on the low side between suction temperature and saturated vapor is superheat, not subcooling; a difference between ambient and condenser liquid temperature isn’t a standard measure; and adding temperatures together doesn’t convey a meaningful refrigerant condition.

Subcooling is the cooling of the condenser liquid below its saturation temperature at the high-side pressure. In practical terms, it’s the difference between the condenser liquid temperature and the saturated liquid temperature at the high-side. Keeping the liquid subcooled ensures it reaches the metering device as a fully condensed liquid, which reduces flash gas, improves compressor efficiency, and helps control the refrigeration system. The other descriptions mix in concepts that aren’t subcooling: the difference on the low side between suction temperature and saturated vapor is superheat, not subcooling; a difference between ambient and condenser liquid temperature isn’t a standard measure; and adding temperatures together doesn’t convey a meaningful refrigerant condition.