In addition to biomass, there are other forms of renewable heat technology that capture heat from the soil, or water or from the air. A ground source heat pump works by extracting heat stored in the ground and passing it through a heat exchanger to raise the temperature of water high enough to be able to heat a building. Most systems use heat collecting pipes that are buried in loops in shallow trenches. The size of any system is therefore dependent on the area of land available to install the ground collector loops – an important factor if you are looking at heating a large community building. It is also possible to place the heat collector in a vertical borehole, which only needs a limited surface area for access.
Heat pumps require a source of conventional energy to power the pumps and compressors needed to run the system. Typically this uses only a quarter of the amount of energy released into the building.
Water source heat pumps extract heat from a body of water such as a river, lake or even the sea.
An air source heat pump extracts heat from the outside air, in much the same way that a fridge extracts heat from its inside. Heat from the air is absorbed at low temperature (down to as low as -15° C) and into a fluid. The fluid then passes through a compressor, where its temperature is increased, before being transferred to the heating or hot water system of the building.
The two main types of air source heat pump systems are air-to-water, where heat is distributed via a conventional central heating system, and air-to-air, where the system produces warm air which is circulated by fans.
As heat pumps work much more efficiently at a lower temperature than a standard boiler powered central heating system they are best suited to underfloor heating systems rather than conventional radiators. For this reason, they are most commonly installed into new properties where there is no need to ‘retrofit’ the heating system.
Solar thermal panels work on the same principle as solar pvs in that they collect solar energy, in this case heat, and use it to warm water. The system works all year round, though in Wales the panels may require a little help from an immersion heater during the winter months. Solar thermal panels can be hooked up to central heating systems, though general the heat gain is too small to be worthwhile and their use is primarily restricted to supplying the hot water system of a building.
More information on how you might fund your project can be found on our Funding page.
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