Deutsche Flugsicherung, Langen, Germany

Office building for the headquarters of DFS, the German air traffic control; the building fulfilled “low energy office” criteria in force at the time of construction

Project details:

  • 154 Borehole Heat Exchangers (vertical loops), each 70 m deep
  • 340 kW of heat and cold exchanged with the underground
  • The geothermal system provides base-load heat and cold to the building, with classical air-cooled chillers and a connection to district heating for the peaks
  • First commercial BHE design in Germany based on ground investigations using TRT
  • A monitoring campaign in 2009-2011 proved superb efficiency, with SPF of about 6 in heating mode and 10 in (direct) cooling mode
  • >30.000m²

Heat pump for DFS building (left) and first-generation TRT equipment on the construction site in 1999 (right):