Geothermal probe heat pumps take their energy from geothermal probes that are fed into the deeper layers of the earth. These geothermal probes consist of a brine pipeline that is led downwards in vertical boreholes, some of which are very deep, and, after the turning point at a depth of approx. 40 - 100 m, back to the surface. The temperature in the ground is constant from a depth of approx. 10 m and is not subject to seasonal fluctuations. This makes the geothermal probe a very effective source of energy, especially in winter. In summer, a passive cooling effect can also be carried into the building from the relatively cool ground by the heat pump.
The following factors have an influence on the number and depth of the geothermal probes:
Certain layers of earth must not be penetrated with the probes, which is why the geothermal probes are always subject to approval. As a general rule, a few probes with a great depth can be produced more economically than several probes with a lower depth. At the head of the geothermal probe, a shaft is usually created from concrete rings including a cover so that the borehole remains accessible. For an average newly built single-family house , the total drilling depth is approx. 100 to 150 m. Depending on soil conditions and approval, this can be divided into approx. 2 to 6 probes. As a first step, an approved expert should be commissioned to examine and demonstrate the possibilities and obtain approval, taking into account the very different applications and notification procedures from country to country. The water management offices usually keep lists of approved experts in the corresponding area. However, the specialist companies carrying out the work also obtain the necessary permits for the applicant if they are commissioned accordingly.
Approval of the construction of geothermal probes: The construction of geothermal probes (deep boreholes) must be approved by the Lower Water Authority. The underlying laws are the Water Resources Act (WHG) and, for depths above 100 m, the Federal Mining Act (BBergG). In regions with a special claim to protection (e.g. water protection areas), additional laws must be taken into account.
Notification of boreholes: Boreholes for geothermal probes are generally subject to notification. The so-called "drill notification" must be made at least one month before the start of the drilling work at the responsible state office or district office.
1: Heat pump
2: Buffer tank
3: Return flow
4: Flow
5: Shaft head
6: Geothermal probe
Source: bauwion
