AIR-CONDITIONERINTRODUCTIONAir conditioner or AC is a home appliance that is designed to change the temperature of air and humidity in the air into a more desired condition within a particular space, area or room. Air conditioners use refrigeration to cool the temperature in a room. Refrigeration is a process of work that is done to move heat from one place to another. Air conditioners also use one major physical law, which states that when liquid changes into gas, heat is absorbed and when gas changes into liquid, it gives off heat. Air conditioners use refrigerants to carry out this phase conversion from liquid to gas that absorbs heat. A refrigerant is a liquid that is capable of vaporizing at atmospheric pressure.Air conditioners use fans to move warm indoor air over the evaporator coils that are filled with these refrigerants. When hot air flows over the evaporator coils, the liquid refrigerant absorbs the heat as it evaporates and cool air flows out into the room. To keep the cooling system going, the refrigerant, which is now in a gaseous state, has to be converted again into a liquid. Air conditioners use a compressor and a condenser to change the refrigerant gas into liquid by using high pressure and cooling it down. Compressing the gas will create extra heat that it is then directed into the condenser coils using a second fan. The condenser coils cool down the liquid from the compressor. Now the refrigerant is back at its liquid state and the process begins all over again. There are basically two major things that are happening in the process of air conditioning. First, refrigerant is cooling the indoor air. And second, the gas product is compressed and cooled so that it can be converted back to liquid again.