The university city of Freiburg is home to an innovative city hall that is now the biggest surplus-energy building in Europe. The building boasts outstanding thermal insulation that allows for low-temperature heating and high-temperature cooling. To minimise energy demand, the building is fitted with a ventilation system that uses heat recovery. The building is heated and cooled efficiently by using energy in the ground water.
A heat pump operates the heating system and a plate heat exchanger is used for cooling. The roof and areas of the facade exposed to direct sunlight are fitted with high-performance solar energy panels, which also shield the building from the sun. The overall result is an energy concept that enables the building to make good use of renewables and thus generate more energy than it requires for heating, cooling, ventilation and lighting. This is because the photovoltaic units produce more electricity than the building needs. The building also reacts to network requirements, so it can feed surplus electricity back into the grid.
AT A GLANCE:
Award Climate Positive*
Year of the award: 2019
Valid to: September 2020
Location: Freiburg, Germany
Applicant: Drees & Sommer
Client: Stadt Freiburg
Architect: ingenhoven architects
Energy concept and CO2 balancing: Drees & Sommer SE
* This award is bestowed for buildings that achieve a negative annual carbon footprint and thus make a significant positive contribution to climate protection. The net carbon footprint assessment is based on the DGNB Framework for Carbon-Neutral Buildings and Sites.