Pompe à chaleur et stockage de glace pour chauffer et refroidir un immeuble de bureaux allemand neutre en énergie. (en anglais)

Schnepf, a German company, has designed its new 2,500 m2 office building with an innovative energy concept, combining ice storage, a heat pump and solar energy. The centrepiece of the facility is a subterranean ice tank with a 350 m³ capacity and around 6 km of closed-loop piping. Filled with a mixture of water and anti-freeze, this serves as a heat exchanger for the brine/water heat pump installed within the building.

During the heating phase, heat is drawn from the water in the ice tank and delivered to the building via the heat pump. The further withdrawal of heat causes ice to form on the piping. This ice layer expands within the ice tank from the inside outwards during the heating phase. At the end of the heating phase, the ice tank contains almost 100% ice. In the subsequent warm season, the stored ice is used to cool the building. This natural cooling process is used until the ice has fully melted and the water temperature in the tank rises to approx. 10°C. As a consequence, around 70% of the cooling energy required in summer is naturally covered by the stored ice. If the water temperature in the tank continues to rise, the heat pump can also be used as a cooling unit. Waste heat from the pump is in turn now stored in the ice tank, whereupon a new sequence can now begin.

On the roof of the building is a 320 m2 photovoltaic system for power generation with a peak capacity of 50 kWp and an annual output of approx. 46,000 kWh. The power generated covers the building's usage, with any excess power then fed into the grid.

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