Climate-friendly heating and cooling solution for a LEED Platinum-certified office building
Ambassador House in Opfikon, which dates back to the 1980s, was completely renovated over the course of four years and awarded the US LEED Platinum label for sustainable construction. This sustainability certificate means that the property meets the highest environmental,
economic and social standards.
The office and service building has a volume of around 200,000 m³ over 10 floors. The newly created, innovative infrastructure provides companies with attractive office space and conference rooms. Co-working spaces, a cafeteria and a daycare centre are also included.
In addition to the new exterior, the building also received state-of-the-art building services including two large ammonia heat pumps to provide a 100 per cent carbon-neutral energy supply. Waste heat from the SBB frequency converter plant is used for this purpose.
Cost-effectiveness and the environment in harmony
The energy supply was a key aspect of the renovation of this impressive building . The tender wanted a district heating supply of 80 per cent fossil-free energy via a third-party contractor . Our business solution was implemented and enables a supply of 100 per cent fossil-free energy. For more than 10 years , we have been using waste heat from the SBB frequency converter plant at a temperature of around 50°C for an adjacent building. ‘General contractor Halter approached us with its concept of an energy solution for the Ambassador House . We still had enough waste heat available from the SBB converter plant, as the potential here had not yet been exhausted. We were therefore able to offer this more environmentally friendly solution at considerably lower operating costs,’ explains our project manager Pascal Leumann.
Guaranteed energy supply
We transport the heat from the transformer plant to the energy centre at Ambassador House using specially laid district heating pipes. To do this, we had to lay the line under the railway tracks using a press-drill tunnelling method. Using the waste heat also reduces the recooling effort for SBB. The use of this waste heat therefore offers a clear advantage for both partners.
The energy centre at Ambassador House is equipped with two large heat pumps/cooling machines that use renewable energy and the natural refrigerant ammonia (NH₃). If no waste heat is delivered from the SBB converter plant, we operate the two ammonia cooling machines as air/water heat pumps and ensure the heat supply is 100 per cent carbon-free. The two ammonia cooling machines also provide the cooling needed to cool the offices and server rooms.
A joint network was built to distribute heat and cooling, which is operated hot in winter and cold in summer. Hot water is heated in a decentralised way in the three parts of the building using efficient heat pumps that use the heating/cooling network as a heat source.
This innovative energy concept enables 680 tonnes of CO₂ to be saved per year. ewz planned, financed and built the energy centre and will operate and optimise the systems on an ongoing basis for 30 years.
- Planning, implementation, financing
- Heating/cooling solution using NH₃ heat pumps, with waste heat and outdoor air as energy sources
- Recooling system
- Operation of the energy systems
- 2,300 MWh/a energy for heating and hot water, 100% carbon-neutral
- 150 MWh/a energy for cooling
- 680 tons of CO₂ saved per year
