Pipe work known as the ‘ground loop’ is buried in the ground and a pump contstantly circulates a mixture of water and antifreeze around the loop. Heat from the ground is absorbed into this liquid which is passed through a heat exchanger in the heat pump.
Low grade heat is now extracted by the refrigeration system and after passing through the heat pump compressor is concentrated into a higher temperature which can now be used to heat water for heating systems and / or hot water use.
The now cooler ground loop liquid passes back into the ground where it absorbs further energy from the ground in a continual process.
The length of the ground loop needs careful calculation according to the amount of heat required and to avoid extracting more energy from the ground than can be replenished by solar radiation.
The loop is normally installed flat or in coils around 1-2 metres deep.
Heat pumps require electricty to run but a typical system will deliver approximately 3 units of heat for every unit of electricity used to power the pump.
Air Source Heat Pumps
An air source heat pump works in much the same way as your fridge except heat is extracted from the outside air. Even when the air temperature outside is below freezing the heat pump will still extract usable heat.
Heat pumps need electricity to operate but the heat extracted from the air is constantly being renewed so as long as you have an electricity supply then you have heat.
The usable heat is at a lower temperature and delivered over longer periods than a conventional gas or oil fired boiler, consequently the radiators will feel cooler to the touch than with a conventional heating system. During the coldest months of the year the heat pump will need to run constantly to heat your home efficiently.
Benefits of Air Source Heat Pumps: