Underneath the parking lot of a new office building in Nagold, Germany, a large, 300 m3 ice-storage tank can be found. It is part of an innovative energy concept, where 100% of the building’s heating and cooling demands are provided by regenerative energy sources. The whole building is heated and cooled via water pipes embedded into the concrete ceilings, always keeping the surface temperature close to the air temperature in the office space, thus providing a comfortable environment, despite the large glass surfaces around the building. The heating and cooling system consists of an ice-storage tank, a large heat pump, and a solar/air absorber mounted on the roof, along with a photo-voltaic installation providing the electricity to power the heat pump. The main heat sources are the 42 roof-mounted solar/air absorbers operating at low temperatures, which produce more energy than classical solar installations, as heat can be collected even on cloudy days.
The system is independent from seasonal variation, as surplus energy is stored in ice-storage tank for later use. At the heart of the system is a heat pump, using the ice- storage tank as heat source, providing energy for both heating and hot tap water. Energy provided from the roof absorbers and the surrounding melts the ice again, creating an infinite heat source for the heat pump. Such phase changes in the water allow to store or release large quantities of energy while keeping the size of the storage moderate. The heating and cooling power of the system is 73 and 100,8 kW, with a COP of up to 4,9 and a maximum heating temperature of 60°C.
The presentations from our webinar on "Large Heat Pump Applications in Europe: 15 success stories" are now available here