An air conditioner uses something called refrigerant. In a hot room, the refrigerant will take away the heat from the room. The heat will evaporate. The more the refrigerant contacts, the more heat it will take away.
A compressor is another part of an air conditioner. If the refrigerant is like blood, then the compressor is the heart.
The refrigerant that passes through the compressor goes to the condenser. The purpose of the condenser is to receive the high-pressure gas from the compressor and convert this gas to a liquid. This is done by taking away the heat.
The refrigerant flows into the expansion valve. The path gets more narrow, and the refrigerant is split into many pieces. This is like water behind a spray.
As the pressure drops, the temperature dramatically drops, too. The evaporator takes the lower temperature refrigerant and evaporates it again. The cold air is transferred out of the air conditioner.
