Sub-Cooling

Sub-Cooling 

- Sub-cooling is a temperature below saturated pressure-temperature. Sub- cooling is a measurement of how much liquid is in the condenser. In air conditioning, it is important to measure sub-cooling because the longer the liquid stays in the condenser, the greater the sensible (visible) heat loss. Low sub-cooling means that a condenser is empty. High sub-cooling means that a condenser is full. Over filling a system, increases pressure due to the liquid filling of a condenser that shows up as high sub-cooling. To move the refrigerant from condenser to the liquid line, it must be pushed down the liquid line to a
metering device. If a pressure drop occurs in the liquid line and the refrigerant has no sub- cooling, the refrigerant will start to re-vaporize (change state from a liquid to a vapor) before reaching the metering devise.