The existing main train station will be replaced by a new building, which will be a striking 60m/200 feet structure. The base area will accommodate the 2-story station concourse, plus retail shops on the ground floor and administrative rooms for Deutsche Bahn on the first floor. Separated from this, a narrow high-rise cube with planned office and hotel space is being built above it. One floor in between is to serve as a plaza with a roof garden. An external staircase on the level of the station concourse and platforms will offer access to the station.
In the early planning phase, the energy and sustainability concept developed by Transsolar is based on the approach of setting the course for a highly efficient building with low-temperature systems. This allows for a particularly effective use of locally available renewable energies such as geothermal energy. In this case, the potential of the location was already analyzed before the design phase and a simple and robust room air-conditioning concept was developed from this, which allows the highest possible comfort and flexibility with low technical and energy expenditure.
Basic conditioning is achieved by activating components in the ceiling; operable windows provide ventilation for most of the year. Comfort control by tempering the supply air in both cold and hot seasons is achieved by so-called ‘supply air convectors’, which are also operated at a low temperature level and maintain the desired comfort in the interior based on air quality and temperature. The exhaust air flows over the core areas and is discharged centrally with heat recovery. This avoids a central ventilation system and therefore lowers energy consumption. Heat is largely provided by a geothermal system, combined with free cooling in summer. A gas boiler and a chiller supplement during peak loads only.
In order to be able to operate the low-technology concept at low temperatures, requirements were defined for the thermal performance of the façade and robustness of the building, which the participants in the competition had to meet. Thus, sustainability is an important supporting base and is already implemented in the design of the building, combining minimum resource requirements with high comfort.