Modernization of Karlsruhe Stadthalle - The geothermal construction site is running according to plan

Karlsruhe, 4.03.2024 - Anyone who has crossed the inner-city fairground in recent weeks will have noticed the extensive barriers around the Stadthalle, which is currently being modernized. Behind the fences, the company Krämer Brunnenbau & Energie GmbH from Dettenheim is creating the conditions for near-surface geothermal energy.

To date, the four 21-metre-deep boreholes to the west of the Stadthalle have been drilled into the sandy, gravelly ground as planned. The trees standing here have all been preserved thanks to careful planning and the involvement of the gardening department.

The three eastern boreholes between the Stadthalle and Novotel will follow in the next few weeks. The geothermal project will then be completed by the drilling shaft structures as the "head" of the boreholes with their pumping and extraction equipment, as well as the trenches and channels connecting the drilling points with the building and the central building services units. Two planning offices and two other specialist contractors from Karlsruhe and the region are involved. The project will be completed by August 2024.

"It is important that sustainability is also the focus of the modernization of the Stadthalle, which will once again be an important meeting place for citizens in the future," says First Mayor Gabriele Luczak-Schwarz. "The Stadthalle's geothermal project can therefore also point the way for other future-oriented, sustainable projects in the city of Karlsruhe."

Britta Wirtz, Managing Director of Karlsruher Messegesellschaft, which will operate the modernized Stadthalle, emphasizes: "Our customers attach great importance to sustainability and individual concepts in terms of space, lighting control and comfort. This will open doors for us. We are already noticing this as we start marketing the hall."

Groundwater use is environmentally friendly and regenerative

The concept for near-surface geothermal energy follows a simple circulation principle. The groundwater is extracted at a depth of 21 meters to the east of the Stadthalle. The water is then channeled through the building into a heat exchanger, which uses the water for cooling in summer and heating in winter. On the west side, the water is fed back into the groundwater via four seepage wells. The extraction and reintroduction are calculated in such a way that, on the one hand, only minimal and barely measurable groundwater fluctuations are generated and, on the other hand, the temperature of the groundwater remains constant throughout the year. The use of groundwater is environmentally friendly and regenerative, replacing the previous CO2 intensive heating and cooling system of the Stadthalle, which was largely operated with fossil fuels.

Significantly higher energy efficiency amortizes the investment costs

Significantly increased energy efficiency is another major benefit of the modernization. Additional active and passive systems in the building services, such as sophisticated control technology, as well as solar control films for the sloped glazing will significantly reduce the overall energy level. In short, this means: less energy consumption than before, which is also environmentally friendly and regenerative. The investment costs have already been reduced, depending on the approach of energy cost forecasts, will have paid for themselves within seven to ten years amortized. With a new life cycle for the Stadthalle of 30 - 50 years, this is a very good value and a good and solid investment for the future.

"We are delighted that the ambitious geothermal project has worked so well so far. On time and on budget. Not only in the planning and design, but also in the approval process and in the construction work carried out so far," says project manager and architect Matthias Kraemer from general planner SSP AG reports.