Air Conditioning  —  Heat Pumps  —  Ventilation  —  Dehumidification

How Air Conditioning / Heat Pumps Work

"A very basic introduction to the refrigeration cycle"



air conditioning heat pump cycle

Outdoor Unit

1. The Compressor: Raises the pressure of low-pressure low temperature refrigerant vapour to high-pressure high temperature vapour.

2. The Condenser: Changes the state of high-pressure, high temperature vapour to high-pressure, high temperature liquid by cooling the refrigerant. This is achieved by rejecting the heat to the outside by passing ambient air (known as air-cooled) over the condenser fins.

Indoor Unit

3. The Expansion Device: The purpose of the device is to change the state of the refrigerant from high-pressure, high temperature liquid to low pressure low temperature saturated liquid. This is achieved by passing the liquid through an orifice then into a larger pipe which reduces the pressure .

4. The Evaporator: Absorbs the heat from room air as it passes over the fins, which evaporates the refrigerant. This will change the state of low-pressure, low temperature saturated liquid to low pressure, low/medium temperature refrigerant vapor which is then sucked back to the compressor.

Heat Pumps

Modern units can Cool in Summer & Heat in Winter. By using a special change over valve the refrigerant cycle can be reversed so that the Indoor unit now rejects the heat into the room and the outdoor unit absorbs heat (even at very low temperatures) from the outside air.

For further information on Heat Pumps, how heat pumps can save you money & reduce your carbon foot print. Please look at our heat pump page.