• License# CR110184

  • In today’s competitive service market, every conscientious service technician should understand why a refrigeration or air conditioning system must have the proper amount of liquid subcooling. The amount of liquid subcooling not only affects system capacity, but also the effectiveness and capacity of expansion type metering devices. Subcooling is defined as the difference between the measured liquid temperature and the liquid saturation temperature at a given pressure, or any sensible heat taken away from the 100 percent. The saturated liquid point in the condenser can be defined as liquid subcooling. Liquid subcooling may occur from the start of the 100 percent saturated liquid point in the condenser to the metering device. The saturated liquid temperature can be obtained from a pressure/temperature relationship chart using the condensing pressure. This means that as soon as all of the saturated vapor in the condenser changes phase to saturated liquid, subcooling will start to occur if any more heat is taken away. Remember, this is now a temperature change or sensible heat change. So, any drop in temperature of the liquid below the saturation temperature for the pressure at that point will be considered liquid subcooling. There are two subcooling categories: condenser subcooling and total subcooling.