The air conditioner condenser is the system component that removes heat from the system. The condenser is a heat-exchange surface that permits the transfer of heat from the system refrigerant to the air outside. The heat comes from the space that is being cooled and from the heat generated during the compression process. The air outside for residential systems, must be at a lower temperature than the refrigerant to allow heat transfer to occur. This rejection of heat causes the hot vapor refrigerant coming from the compressor to condense. The purpose of the condenser is to condense
the refrigerant to a liquid. The temperature at which the refrigerant will condense is called the condenser saturation temperature
The Condensing Process
The refrigerant leaving the compressor is superheated and well above the saturation temperature, so it must first be cooled before it can condense. The process of removing the superheat from the discharge refrigerant is referred to as desuperheating. The desuperheating process removes superheat and is a sensible heat exchange since it can be measured with a thermometer. Although the temperature is changing, the pressure will remain the same. The purpose of the first process is to reduce the refrigerant to the condenser saturation temperature.
Once the refrigerants temperature drops to its condenser saturation temperature then it will begin to change state. The second process of the condenser is to change the refrigerant from a vapor to a liquid. The refrigerant goes under a latent heat transfer which cannot be measured, when changing from a vapor to a liquid. Since the refrigerant is still warmer then outside it will still continue to give away heat as a liquid. The condenser has condensed the refrigerant.
Subcooling is the third process of the condenser it cools the refrigerant to a temperature below the condenser saturation temperature. One degree of subcooling is one degree below the condenser saturation temperature. Ideal subcooling temperature is about 20 degrees below the saturation temperature. Subcooling gives the system a high-pressure high-temperature liquid to enter the metering device.
Silberstein, Eugene. “Condensers.” Residential Construction Academy: HVAC, Second Edition. Clifton Park, NY: Delmar, 2012. 34-35. Print.