Design-Hotel Kameha: Geothermal energy for the Bonner Bogen

The Kameha Grand design hotel, opened in 2009 in Bonn, provides the newly developed "Bonner Bogen" area on the banks of the Rhine with heat: A geothermal system heats well water up to 50 degrees Celsius. An aquifer – an underground water-bearing layer – ensures that the system provides 60 to 80 per cent of the required heat even in winter. Reversible heat exchangers also make it possible for the system to cool in summer.

The Hotel Kameha Grand uses an energy concept, which reduces the burden on the environment and makes the buildings independent of fossil fuels. The key here is: The design hotel utilises the heat from the groundwater to supply the 60,000 m2 of office, hotel and restaurant space with heat and cooling...

Engine for progress:

  • saving of 400 tonnes of CO2 per year
  • saving of 1,700 MWh of primary energy per year
  • innovative, economical energy concept
  • one of the largest systems of this kind in Europe

1 of 5

Photo: BonnVisio Gruppe

The newly developed Rheinbogen in Bonn consists of a building complex with 60,000 m2 of office, hotel and restaurant space on the site of an old cement works. 80 per cent of this complex is supplied with heating and cooling from groundwater by six wells, which are distributed across the site.

Heat from the aquifer

The main component of the novel energy concept is a geothermal energy system, which uses a suction well that reaches to a depth of up to 28 metres to extract water from an aquifer. Heat exchangers transfer the heat to a secondary circuit and increase the temperature by means of heat pumps from around 13 °C to 50 °C. Because the heat pumps are reversible, in summer the temperatures can be reduced to about 6 °C, thus covering almost the entire cooling requirements of the building. The water is then sent back to the aquifer via a second well.

Energy efficiency and electromobility

Furthermore, the Kameha Grand Hotel improves its energy efficiency through many smaller measures: The hotel uses LED lighting and motion detectors in areas open to the public, thereby reducing electricity consumption. Guests can also rent e-bikes and electric cars.
The renowned MIPIM Award from the international real estate industry confirmed the architectural and energy-efficient quality of the project in 2010.

Photo: BonnVisio

"With this system, we save around 1,700 MWh of primary energy and 400 tonnes of CO2 each year. The efficient geothermal system in conjunction with the optimised aquifer storage system make this possible, along with a building concept with a low temperature level and the continuous optimisation of building technology and room controls."

Martin Jung, Managing Director EcoVisio GmbH

Partners and sponsors

  • BonnVisio-Gruppe
  • Kameha Grand Betriebsgesellschaft mbH