Location: Freiburg im Breisgau, Germany.

Architect: ingenhoven architects.

The new town hall in Freiburg im Breisgau, opened in November 2017, is the world’s first public building to net-surplus-energy standard. The building generates more energy than it consumes, with the excess energy fed into the city grid. The primary energy demand of the town hall for heating, cooling, ventilation, and hot water supply is as low as 45 kilowatt hours per square meter per year, which is only 40% of the primary energy demand of comparable modern office buildings. The energy required for the building is generated via suction and injection wells, thermal solar panels in combination with heat pumps, and photovoltaic panels on the roof and in the facade. The energy for cooling and heating is obtained from a geothermal installation. The room climate concept of the offices involves thermal mass activation, heating/cooling sails, external solar screening, triple glazing, and mechanical background ventilation with heat recovery, which are all part of the energy-saving concept. The citizens’ service center with its approximately 100 employees offers citizens general and advisory services. All offices and workplaces have been designed for functionality, openness, and working in a flat hierarchy, whilst providing privacy and security. The overall space has a generous and flowing flair thanks to its curved design. Large rooflights provide adequate daylight and offer good vistas to the outside. The downlights in the white perforated ceiling panels have been arranged in seemingly random fashion to create the impression of a ‘star-studded night sky’.

Photo credit: ingenhoven architects / HGEsch.