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Fig. 1: The installation of large-module solar roofs saved roof refurbishment costs and on-roof mounting costs.
© Pfeil & Koch Ingenieurgesellschaft GmbH & Co
New storage technologies in use
Projektinfo 14/2009
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School refurbishment combined with local solar heating

An existing local heating structure, buildings which needed refurbishment and the availability of sufficient space for storage tanks and for a solar energy system all spoke in favour of installing a local solar heating system in the school and sports centre in Eggenstein-Leopoldshafen near Karlsruhe, Germany. This was to be combined with a refurbishment of the existing buildings, so as to reduce the heat energy requirement.

The project participants had to harmonise the refurbishment of partially dilapidated buildings with the desire for a high (up to 40%) solar share of fraction. Contrary to common practice, they first refurbished the heating network. This can be seen as an indication of the poor condition of the building services technology. The refurbishment of the buildings occurred in individual steps, as the school had to continue operating. The use of solar roofs helped to save costs during the roof refurbishment. A total collector surface area of 1,600 square metres was installed.


In order to enable solar shares of fraction of between 35% and 40%, the parties responsible opted for seasonal storage, in the form of a gravel/water heat storage tank. Here, initial research results from the laboratory and experimental scale were directly implemented in a large storage tank. This placed new demands on planners, installers and operators, as well as entailing high technical risk. Innovative approaches to the charging and discharging system, sealing design, thermal insulation and the filling of the storage tank posed additional challenges. The storage tank has been charging for some time and is currently in the test phase. The funds for this project are provided by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), among others.


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Planning and construction supervision
Pfeil & Koch ingenieurgesellschaft GmbH & Co. KG

Scientific measurement programme
Universität Stuttgart, ITW

Scientific and technical consultation

Long-term heat storage tanks
Züblin Spezialtiefbau GmbH