EnBW City Stuttgart

Heat generator

Heat/cold consumers

Cold generator



EnBW Group branch

In the south of Stuttgart, the German energy supply company EnBW has built its Group branch on a 35,000 m2 site. EnBW City comprises administrative buildings with a gross floor area of 114,000 m2. EnBW has opted for an environmentally friendly energy concept for this new building and has installed three Zortström collection and distribution centers in the heating and cooling areas.

Three Zortström collection and distribution centers

Heating and cooling in the building complex is provided by concrete core activation. Depending on requirements, the heat pumps for the concrete core activation provide heated or cooled water. The heat pumps produce a total heating output of 1,460 kW and deliver this to an area of 87,283 m² to be heated.

During peak load operation, the heat pumps are supported by a gas condensing boiler and a low-temperature boiler (1,900 kW). The heat pumps run reversibly. Heat is extracted from the rooms via the concrete core temperature control system and transferred to the ground with low energy consumption.

Significant energy savings

The system in EnBW City was originally designed to cover 40% of the heating load and 60% of the cooling load of the heat pumps in the base load range. Today, after installation of the Zortström technology, the values are 57% and 79%. This means that boilers and chillers now only run at 43 % and 21 % respectively, which contributes significantly to energy savings.

The three multi-stage Zortström centers are the heart of the system. They decouple the hydraulics and thus control the optimized use of energy. The result is perfectly coordinated interaction between the individual heat generators and consumers.