The Sustainability Consortium: Making Carbon-Free Living a Reality (Carbon Free Group)
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9. Open (aquifer) system. With this system water heated by the collector is pumped straight into the ground. As a result the ground / groundwater is heated and a so-called “heat bubble” is created With a temperature of up to about 32°C (NT ± 20°C). What is Geothermal storage?
10. Borehole system. In this system the transport medium, heated by the collector, is circulated, during which the heat is transferred to the adjacent storage medium (groundwater or ground). When needed this heat can be withdrawn. This “borehole” system is suitable for higher temperatures than the “aquifer” system (up to 80ºC). There is a distinction between normal storage (up to a depth 50 metres), and deeper storage (over 50 metres up to 150 metres)
11. Phase Change Material Thermal Stores A PCM heat store is a latent energy storage system ideal for domestic and commercial installations. The store will effectively improve boiler efficiency by up to 70% and maximise the solar gain from solar collectors. With 4 times the energy efficiency of water, a PCM energy store allows heat to be stored for longer periods in a smaller area compared with normal hot water storage systems.
12. With the use of a PCM heat storage system it is possible to extend the useful period of solar thermal from 5 to 9 months, reducing the dependency on secondary heat sources such as gas condensing boilers. The result is that PCM stores can act as instantaneous water heaters in a PV-T Solar Energy System