Construction operations are in progress at A. Lange & Söhne. A new building will be opened two years from now. Excavation work is complete and the first building phase has begun. Drilling of boreholes for the extraction of geothermal heat started in early April, as the new manufactory will be heated by means of this environmentally-friendly technology that extracts heat generated naturally in the Earth’s crust.
Glashütte is located in the Erzgebirge mountain range. The principal rock in the region is phyllite, easily recognisable by the silky sheen of its schistose surface. The high quartz content of phyllite endows it with high density and thermal conductivity, making it particularly suitable for geothermal heat extraction. For this reason, the decision was taken at A. Lange & Söhne to adopt this green technology. However, it will only be used in the new manufactory building from 2015 on.
Temperature to a depth of about 20 metres below ground level is subject to the influence of sunshine and climatic temperature variations. Below that depth, it increases by approximately 3 degrees per 100 metres. In Glashütte, the average temperature 125 metres below ground is about 13.3 degrees centigrade.
A total of 57 geothermal boreholes 125 metres deep and no more than 164 millimetres in diameter will be needed for A. Lange & Söhne’s new building. In comparison, a single borehole would be enough for an average detached family house. A probe consisting of two U-shaped plastic pipes made of polyethylene (PE), bundled together in pairs, will be introduced into each borehole. These probes will be filled with water, which will circulate through the loops. In the process, the water will take on the average temperature over the length of the boreholes.
Up at ground level, in the new manufactory, the probes will be joined together and connected to a heat pump, which will act as the interface with the building’s heating system. All year round, the heat pump will use the underground temperature very efficiently to adjust the temperature in the building to the necessary level. The process consumes electric power and for this purpose, Lange will use eco-energy.
In summer, it works the other way round: the air conditioning plant can dissipate heat directly into the probes, using them as a means to cool the building. This raises the average water temperature underground, so that the phyllite stores up this energy for the following winter.
By employing geothermal energy for heating and eco-energy to drive the heat pump, the new Lange manufactory will be a zero-carbon installation that will make an important contribution to climate protection. In comparison with conventional heating systems based on fossil fuels, the use of these technologies will reduce energy costs by more than 50 per cent.