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Heat transition on the island

Environmental and climate protection enjoy high priority on the North Frisian island of Pellworm. Always has been. After all, this gem is located near the coast of Husum in the middle of the Wadden Sea, which is classified as a World Heritage Site by UNESCO. The three recently built terraced houses with ten apartments fit in well because they are provided with climate-friendly heating energy. With heat pumps from NOVELAN.

Energy-saving and climate-friendly


The ten apartments are divided into three houses; two houses with three apartments each and one house with four apartments. It was already clear at an early stage of planning that the residents of the new apartments were to be supplied with heat in the most energy-saving and climate-friendly way possible. So it made sense to rely on heat pumps. The ideal solution would be to use geothermal energy. To keep communal use as low as possible, the developers opted for a decentralized concept in which each residential unit has its own heating system.

In addition to the low level of common property, such a concept has another significant advantage: if each apartment not only generates its own heat for heating but also prepares its own domestic hot water, it no longer qualifies as a large-scale system under the German Drinking Water Ordinance. Compact heat pumps such as the WSV 6 from NOVELAN have an integrated domestic hot water tank. Together with comparatively small pipe sizes between the storage tank and the tapping points, they are considered small systems and do not fall under the elaborate provisions of the Drinking Water Ordinance as they do for large systems.

In addition, this means that each household is responsible for the energy costs incurred for heating and domestic hot water. The power supply to the heat pump simply runs through the apartment's own electricity meter, as with other household appliances.

Heating energy from the earth

deep drilling and ground probes

To develop the heat source, Malte Volquardsen applied for a total of six deep boreholes to insert the earth probes. "The approval for this was completely without problems." The two houses, each with three apartments, are supplied via two 60-meter-deep probes, and two 80-meter probes were installed for the house with the four apartments. Three 500-liter cold buffer storage tanks – one for each house – ensure optimal supply security. These storage tanks supply the individual heat pumps with the pumped thermal energy from the geothermal probes, whose temperature level is around + 6° Celsius.