Geothermal Heat Pumps

Surface collector

During the summer, solar heat is stored in the soil. This is either directly absorbed as insulation or as heat from rain and the air from the nearsurface layer of the soil. Using this energy for heating is a cost effective method. The highest yield can be obtained from soil with a high water content. The heat is extracted from the soil by means of buried plastic tubing. An environment-friendly, non-freezing emulsion of waterglycol circulates in the tubing. The soil above the earth collector may not be sealed off under any circumstances, i.e. by buildings, asphalt or concrete.
Earth collectors do not require a permit. Installation depth is approx. 20 cm under the local frost line.

Ground probe

In the lower subsoil of the so-called “near-surface geothermal layer” lies a heat source which can be utilized all year long, which has an almost constant temperature. It can be used for all possible building types, large or small, public or private. Depending on the region it is also referred to as, “vertical absorption, ground spit or ground lance”. It requires little space and the ground probe can even be drilled on the smallest of plots. Therefore it is ideal for refurbishment or adaptation from a heating system fuelled by fossil fuels to the use of geothermal energy.
As with a surface collector a mixture of waterglycol circulates in a closed circuit (similar to the cooling system of a car). Depending on the necessary size of the heat pump unit Fusion Ltd. ascertains the depth and amount of bore holes in which the u-shaped plastic tubing is installed and pressed, in order to achieve good heat transfer.

Ground Water

If ground water is available and easily accessible, it can be utilized as a heat source due to the fact that it has a temperature of between 7 and 12 °C all-year round. It is advisable not to pump water for single and two-family houses from a depth greater than approximately 15 m. This would lead to expenditures being too high. A distance of approximately 10 to 15 m should be kept between the withdrawal point (supply well) and the reinsertion point (deep-well) and furthermore the flow direction should be taken into consideration in order to avoid a “flow shortcircuit”. These installations require a permit and must meet statutory requirements. However, this is no problem for Fusion specified equipment, due to their ISO 14001-certification. An optimal protection according to §7 MWG is provided by the “separator-exchanger-system”.

Function

The cooling medium (water-glycol) is pumped through the closed circuit by the pump, which is installed in the unit. The medium absorbs the heat from the surface collector, the ground probe or the ground water (via the separator-exchanger) and carries it to the heat pump. The heating pump extracts heat from the medium with the heat carrier (evaporator) and simultaneously brings the refrigerant to a higher temperature level with the heat-pumping process (refrigerator principle). The “de-heated” cooling medium can then extract heat from the soil again and the process repeats itself.