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German Federal Environment Agency moves into zero-energy building

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The staff at the Federal Environment Agency’s research facilities in the Berlin district of Marienfelde can now test the German government’s first zero-energy building during their daily work. The energy supply is based on the exclusive use of renewable energies: a photovoltaic system produces electricity and a heat pump generates the necessary heating and cooling energy. The building is intended to generate just as much energy as it requires within one year.

At about the same time when the designers started planning the new building in 2009, the European Parliament passed a new EU Directive on the energy performance of buildings. This stipulates that the “nearly zero-energy building” standard shall also apply to new public buildings by 2019. The idea was therefore born to realise a sustainable and exemplary office building, which is called “Haus 2019”. Designed by the architects Braun-Kerbl-Löffler in conjunction with the Schimmel building services engineering consultancy, the zero-energy building was created as a model project. The complete energy supply for the building is exclusively based on the utilisation of renewable energies. The staff were able to move into their new home at the beginni ng of September 2013. At the same time, a one-year monitoring programme was started. This will show whether the ambitious aim of operating a zero-energy building has been achieved. The first results are expected at the end of 2014.


Efficient building concept supports zero-energy building
A compact, two-storey building was realised in order to achieve the best possible ratio between the outer wall surface area and the volume. The facade, which consists of prefabricated timber elements, the floor plate and the roof achieve U-values between 0.08 and 0.11 W/m²K. Cellulose was used as the thermal insulating material. The windows with internal solar shading and a U-value of 0.8 W/m²K protect against large heat losses in winter and an excessive heat influx in summer. Air-tight construction prevents undesired heat losses and enables efficient use of the ventilation system with heat recovery. The building, which is built to the passive house standard, achieves a maximum annual heating requirement of 15 kWh/m²a. The large roof light above the foyer and the window doors supply the corridors and staircases with daylight. The large roof provides a sufficient surface area for using solar energy.


Energy concept based on renewable energies
The scientific work conducted at the Federal Environment Agency facility is concerned with water. The existing water basins and ponds that form part of the technical test facilities were therefore integrated into the energy concept. The extracted water provides a heating and cooling source for the electric heat pump. The surface heating and ventilation systems distribute the heating and cooling energy throughout the building. A solar thermal system helps to meet the hot water provision required throughout the year. In accordance with the concept, only electrical energy is required to operate the building; further energy sources are not necessary. The electrical energy is generated using a photovoltaic system. 380 modules with a total output of around 58 kWp are located on the roof. The annual yield is forecast to be around 50,000 kWh. This would therefore cover the estimated final energy requirement of 48,000 kWh per year. The generated electricity is directly used, stored in batteries or is injected into the grid. Around a third of the overall electricity requirement will be used for operating the office equipment. Although the lighting is controlled via presence detectors and in accordance with the daylight, the energy requirement for the lighting also plays an important role. This is roughly the same as that used for the heat pump and the auxiliary energy supplied with highly efficient pumps.