Town Hall, Freiburg
The City of Freiburg in southwest Germany is known for its sunny weather and green ambitions. When an international design competition was held in 2013 for the design of a new town hall, it was obvious that it should be a “green” building. The winning proposal by ingenhoven architects is based on the principles of openness and transparency following the idea of a “green campus” with three buildings and a nursery school. The new Town Hall consolidates the 16 different sites currently used for municipal administration into one central building. The three oval buildings are connected by public open spaces to form an ensemble between a city park and a hospital, with open views and public paths. Furthermore up to 400 apartments are planned to be built during the second stage of construction.
On the ground floors there are public areas, such as the citizen’s forum, conference rooms, a cafeteria and shops. The office levels above are designed to be flexible and reversible. Circulation is transparent and open allowing for easy orientation with communicative areas spreading throughout the building. All offices have been designed with functionality, openness, low hierarchy, privacy and safety in mind. The building is only 14 m deep, making natural cross-ventilation possible.
The main visible feature of the building is a highly insulated wooden façade made of vertical, staggered and cantilevering panels with photovoltaic cells. The floor-to-ceiling glass façade elements allow great use of daylight. Further photovoltaic modules are to be found on the roofs. The façade is made of local wood with triple glazing which allows natural ventilation. An external sunscreen is made of blinds. The façade panels can be opened manually and are perforated for acoustic protection. All rooms have operable windows.
The primary energy requirement of the Town Hall will be only around 45 kWh/sq m/a for heating, cooling, ventilation, lighting and hot water. The need for heating is only 15 kWh/m²/a, meeting the strict Passive House Standard criteria. Over the course of a year, the building will produce more energy than it consumes. Excess energy will be fed back into the grid. Energy for both cooling and heating will come from geothermal plant. Heating is done using thermal activation of the slabs and can be controlled individually. The mechanical ventilation is connected to a heat exchanger. The building, which is scheduled to open in 2017, aims for the highest “DGNB gold” green building certification.