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Large storage demonstrator during construction: Use of various segments for testing purposes
© Thorsten Urbaneck, TU Chemnitz
More efficient use of waste heat

Heat storage system with segmental design demonstrates its qualities

In the “OBSERW” research project researchers have developed an innovative above-ground storage tank built using a cost-saving segmental construction method. This required a complete overhaul of conventional storage constructions and building technology. Numerous technical issues were put to rest, such as the temperature-resistant sealing of segments. The storage tank is suitable for water volumes of between 500 and 6,000 m3 and can be operated at storage temperatures of up to 98 °C.

Surplus heat is produced in large measure in supply systems using combined heat and power generation and solar thermal energy as well as in industrial processes. Using storage technology, this thermal energy can be supplied to consumers at a subsequent point. By uncoupling energy generation from energy consumption, the energy utilisation of fuel and the proportion of renewable energy sources can be increased significantly in energy supply.

In heat supply systems with supply temperatures below 100 °C, large above-ground heat storage systems can be advantageously configured as flat-bottom tanks. The compact shape enables very low setup costs and heat losses. The segmental construction of such flat-bottom tanks has already proven effective in cold water storage systems. Energy supplier “eins energie in sachsen/inetz” for instance has been operating a storage tank holding 3,500 m³ of cold water with direct loading and discharge since 2007. Researchers at the Chemnitz University of Technology and the University of Stuttgart have now laid the ground work for similar heat storage systems with high water temperatures together with industry partner farmatic tank systems. Results of material testing (sealing, thermal insulation etc.) and practical trials of the wall structure have been carried over into an innovative storage system design. A comprehensive overhaul of the design and holistic optimisation of loading and discharge systems took place in parallel.

The results of testing were developed and sampled on a small trial model with a volume of approx. 100 m3 (as reported by BINE Information Service). The water storage tank is equipped with a radial diffuser, which facilitates highly favourable temperature stratification with high volume flows. Cold and hot testing went well, meaning the innovative storage tank design can now be carried over to larger storage systems.

Further information on the OBSERW project is available in the project business card on the website of the Energy Storage research initiative.

Follow-up workshop

A follow-up workshop took place on 17 May 2018 in Nortorf (Schleswig-Holstein). Researchers at the Chemnitz University of Technology and the University of Stuttgart have presented their findings at the event alongside industry partner farmatic tank systems. The demonstrator and test system at the location could also be inspected.



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Storage development
farmatic tank systems

Accompanying research
TU Chemnitz, PTT

Accompanying research
Universität Stuttgart, ITW


Project website (in German)

Segmental design reduces building costs for tank storage
Project business card of the Energy Storage Funding Initiative

Energy storage systems
Recent reports on research, development and demonstration of energy storage systems