Air conditioners work by removing warm air in an enclosed area and leaving only cooled air to circulate. The cooling effect is achieved by filtering the indoor air through evaporator coils with a cold refrigerant and streaming the cooled air back into the room. This process also effectively dehumidifies the indoor air as the moisture condenses and collects on the coils and then drains away.
Air conditioning units are made up of several important parts: the condenser coil, the evaporator, or cooling, coil, the compressor, the expansion valve and both the interior and outdoor fans. Running through the coils is perhaps the most important element in the air conditioning system: the refrigerant.
The coils in an air conditioner is a continuous system of copper tube that runs through the indoor and to the outdoor part of an air conditioning system. When the refrigerant is compressed on the outdoor condenser coils, it heats up and a fan blows away some of the heat into the outdoor air. As the compressed refrigerant reaches the expansion valve to pass through the indoor evaporator coils, the sudden expansion of the refrigerant dramatically lowers its temperature. The refrigerant further cools down as warm indoor air passes through the coils, thus cooling and dehumidifying the indoor air at the same time.
Refrigerants are mistakenly referred to by some as "Freon," which is actually a brand of the R22 type of refrigerant manufactured by DuPont. Due to its negative effect on the ozone layer, R22 refrigerants are being phased out by the United States government in favor of the environmentally friendlier R410A refrigerant.