Near Innsbrucker Platz, the office high-rise "The Friedenauer" is being built as an energy-efficient pilot project for a sustainable energy supply in Berlin. In the new OFB construction project, GASAG Solution Plus is relying on a fully electric solution that provides heating and cooling exclusively from renewable sources and sets new standards for the technical use of urban energy potential. In the future, the building will be supplied by wastewater heat, reversible heat pumps and large-scale photovoltaic systems. In addition, the waste heat from the server room is integrated into the heating system and secured by a power-to-heat boiler. "The Friedenauer" is the first building in Berlin to obtain its heating and cooling supply entirely from a gravity combined sewer.
Consistent waste heat concept and 100 percent renewable
The completely renewable supply is based on three reversible heat pumps, which enable both heating and cooling of the surfaces. Two heat exchangers installed in the combined sewer tap into the temperature level of the wastewater and supply the basic energy for the system. A cold network connects the sewers and the office properties with each other.
Four buffer storage tanks, each with a capacity of 5,000 litres, ensure security of supply, especially in times of lower wastewater volume and temperature. In exceptional cases, a 600 kW power-to-heat electric boiler is available as a backup solution.
Another element of the energy concept is the server rooms of the office property. The servers are also cooled by the wastewater and are secured by a recooler; an expansion option for a second server system is planned. In winter, the waste heat generated during the cooling process from the server room is used as a heat source for the offices.
In the future, a large-scale photovoltaic system will generate its own electricity for the operation of the energy centre and thus strengthen the consistent electrification of the building system. Surpluses are fed into the power grid.
Use of wastewater heat as a key technology
The use of wastewater heat is considered a particularly reliable and climate-friendly source of energy. The constantly available temperature level of usually 12 to 23 °C allows efficient heat and cold generation.
The close cooperation with Berliner Wasserbetriebe will result in the first large-scale office project in Berlin to use this technology. The pilot project is an example of how urban infrastructures can be intelligently integrated into sustainable supply concepts.
Matthias Trunk, GASAG Chief Sales Officer: "For us, the success of an energy concept is determined by the fact that an innovative idea becomes a reliable supply system that can be operated efficiently and economically in everyday life. At "The Friedenauer", we rely on the integration of wastewater heat and heat pumps into a holistic, electrically based supply system. The excellent cooperation with OFB shows how such solutions can be implemented in an urban context in a practical and reliable way."
Dr. Bernd Schade, Chairman of the Management Board of OFB Projektentwicklung GmbH, explains: "With "The Friedenauer", we are consistently focusing on a state-of-the-art energy concept with a focus on energy efficiency and the use of wastewater heat. In this way, we make an important contribution to the reduction of fossil fuels and at the same time strengthen the energy independence of the property. We would like to thank GASAG Solution Plus, which is supporting us as a strong partner in the development of the technical solution and in the upcoming implementation of this innovative concept."
From left to right: Karin Richter, Bernd Schade, Thomas Löbel (ÖFB), Matthias Prennig, Matthias Trunk (GASAG). Photo: GASAG Group
Part of a long-term neighbourhood development
The eleven-storey office high-rise "The Friedenauer" offers around 21,000 square metres of rental space for offices, gastronomy and retail and marks the completion of the Friedenauer Höhe district development. The project is consistently geared towards sustainability and is striving for DGNB Gold certification.
Friedenauer Höhe has developed into a modern urban quarter with more than 1,100 apartments in several construction phases. GASAG Solution Plus is responsible for the underlying energy concept. The area is supplied by a biomethane combined heat and power plant, supplementary natural gas boilers and relies specifically on renewable components.
"The Friedenauer" ties in with this overall concept. The real estate shows how climate protection, energy efficiency and urban densification can be sensibly combined in an urban context. It is thus considered a model for future urban districts and illustrates that the energy transition can be implemented not only in wind farms and solar fields, but also in urban areas.
The start of the implementation of the energy supply for the new office building is scheduled for the fourth quarter of 2026 as part of the ongoing construction process. The systems will be commissioned in parallel with the overall completion of the building in the third quarter of 2027.
The eleven-storey office tower "The Friedenauer" in Berlin. Graphic: OFB
