- Air conditioners use a liquid called the refrigerant, which is circulated continuously by a powerful pump called the compressor. Most air conditioners use centrifugal compressors, which look like fan turbines. The centrifugal compressor spins very fast, and as it turns the refrigerant is forced outward along its curved blades and propelled into the condenser.
- The fluid in the condenser is pressurized, which causes it to heat up. The condenser is a long coil made out of metal, and heat leaks through it very easily. In most air-conditioning units, the condenser coil is kept outside so that this waste heat can flow out into the air. In some cases, the condenser is kept underground instead and the waste heat flows into the earth.
- At the end of the condenser is a narrow nozzle that sprays the refrigerant into a low pressure chamber called the evaporator. When fluids such as the refrigerant go from a high pressure area to a low pressure area, they expand and drop in temperature. Like the condenser, the evaporator is a long metal coil. Air is blown over the coil by a fan. As the air passes the coal coil, its heat gets sucked into the refrigerant. This creates a stream of cold air. At the end of the evaporator, the refrigerant is sent into the condensor again, starting the cycle over.
