Freiberg Regional Hospital

Like the geothermal mine water system at the Reiche Zeche, Freiberg Regional Hospital also uses the mine water from the Himmelfahrt Fundgrube in the Freiberg mine district, namely that directly surrounding the Old Elisabeth mine shaft. The mine water is pumped in an open circuit from the Rothschönberger adit to a heat exchanger located in a room in the third level of the mine. After the heat is transferred to a closed intermediate heating loop, the mine water is discharged to the Rothschönberger adit downstream of the extraction point. The water in the intermediate circuit is pumped to the surface, where it is used directly for cooling the hospital rooms during the summer months. The primary duty of the system, however, is to supply heat to the hospital during the winter, in which case a heat pump is employed to increase the temperature of the water before use.

Geothermal mine water system at the Freiberg Regional Hospital (Graphic: Freiberg University of Mining and Technology)

The heating system is supported not only by a natural-gas boiler but also by a combined heat and power unit, which supplies electricity to the heat pump. With 600 kW of cooling and 860 kW of heating output, the system is one of the largest geothermal mine water systems in the world [1]. In addition to using the mine water as an energy supply, the hospital uses the Freiberg mine buildings in another unique way: here, air is conveyed through the main gallery by fans at the gallery entrance, heating or cooling the air to provide air at a constant 10°C year-round. While it flows through the adit, the air reaches almost complete water saturation. Thus, after being heated to approximately 21 °C in the hospital, sterile and dust-free air with a moisture content of approx. 50% is made available, both economically and energy-efficiently [2].


[1] Grab T., Storch T., Groß U. (2018) Energetische Nutzung von Grubenwasser aus gefluteten Bergwerken. In: Bauer M., Freeden W., Jacobi H., Neu T. (Hrsg) Handbuch Oberflächennahe Geothermie. Springer Spektrum, Berlin, S. 523–586
[2] Apenburg K. (2002) Himmelfahrt Fundgrube belüftet Kreiskrankenhaus Freiberg. Informationsdienst Wissenschaft e. V., verfügbar unter, zuletzt aufgerufen am 10.01.2019