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Dining atop a giant thermos

The “energy storage tank of the future” in Heidelberg

The municipal utilities Stadtwerke Heidelberg are installing an energy storage tank with a capacity of 20 million liters to enable more efficient use of heat from renewables and cogeneration. (Copyright: Stadtwerke Heidelberg)

Stadtwerke Heidelberg have just built an enormous hot water storage tank, which is one of the actions listed in the Energiekonzeption 2020/2030, the municipal utility’s green energy plan. The pioneering energy tank was recently filled for the first time with 20 million liters of water and has passed leak tests. In the future, it will hold hot water that can then be fed back into the district heating network as needed. Hot water with a temperature of up to 115°C will be stored in the lower part of the two-zone atmospheric storage tank, which has a volume of 12,800 m³. The upper part of the 55-meter tank will be filled with colder water to create the pressure needed to prevent evaporation and enable storage of hot water even above 100°C. A press release from the municipal utilities sets out their aim to replace the oil and gas heating used during cold snaps with heat from renewables and highly efficient cogeneration processes.

The next step will be to fit the container with a layer of insulation approximately 50 cm thick before cladding it in trapezoidal sheet metal. This is expected to be finished by early August. In the final construction phase, the tank will be given a second envelope in the form of a tensile structure with metallic plates that reflect light and move in the wind. The energy tank is also designed to be an attraction for local residents and visitors to Heidelberg. The plans include an accessible roof terrace, a restaurant with a private lounge, and an indoor space for events. (SP)

For more information, please visit the website of Stadtwerke Heidelberg (in German)