Air Conditioning Australia, your online Air Con Resource

How Heat Pumps Work

courtesy www.oge.com Outdoor condenser units, sometimes called an outdoor coil, are seen in this photo. Courtesy of Smiths Services Brisbane

Reverse cycle systems

A reverse cycle system is one of the best ways to heat and cool your home with electricity. They use as little as one third of the electricity to heat your home to the desired temperature, compared to standard electric heating. A reverse cycle airconditioner, or "heat pump", extracts heat from the outside air and transfers it into your home. This process is reversed in summer to cool your home. They are the most energy efficient electric system to run and will add value to your home.

During the cooler Australian months, why leave your air-conditioning unit to gather dust. By choosing a reverse cycle model, you can take advantage of superb features for a few dollars more..

Imagine that you took an air conditioner and flipped it around so that the hot coils were on the inside and the cold coils were on the outside. Then you would have a heater. It turns out that this heater works extremely well. Rather than burning a fuel, what it is doing is "moving heat."

A heat pump is an air conditioner that contains a valve that lets it switch between "air conditioner" and "heater." When the valve is switched one way, the heat pump acts like an air conditioner, and when it is switched the other way it reverses the flow of Freon and acts like a heater.

Heat pumps can be extremely efficient in their use of energy. But one problem with most heat pumps is that the coils in the outside air collect ice. The heat pump has to melt this ice periodically, so it switches itself back to air conditioner mode to heat up the coils. To avoid pumping cold air into the house in air conditioner mode, the heat pump also lights up burners or electric strip heaters to heat the cold air that the air conditioner is pumping out. Once the ice is melted, the heat pump switches back to heating mode and turns off the burners.

Back to Cooling Mode
Air conditioners employ the same operating principles and basic components as your home refrigerator. An air conditioner cools your home with a cold indoor coil called the evaporator. The condenser, a hot outdoor coil, releases the collected heat outside. The evaporator and condenser coils are serpentine tubing surrounded by aluminum fins. This tubing is usually made of copper.

A pump, called the compressor, moves a heat transfer fluid (or refrigerant) between the evaporator and the condenser. The pump forces the refrigerant through the circuit of tubing and fins in the coils. The liquid refrigerant evaporates in the indoor evaporator coil, pulling heat out of indoor air and thereby cooling your home or small business.

The hot refrigerant gas is pumped outdoors into the condenser where it reverts back to a liquid, giving up its heat to the air flowing over the condenser's metal tubing and fins. Fact Sheet