Long-term Heat Storage Tank
Hot water storage tank in Friedrichshafen, Germany
Picture: The hot water storage tank in Friedrichshafen, Germany (12,000 m³ storage volume) supplies up to 570 living units of the newly built area.

Large solar thermal systems with seasonal heat storage tanks are also tasked with providing solar heat for space heating during winter. Seasonal heat storage tanks are the cornerstones of solar-supported heat. Besides hot water storage tanks made of concrete or fiberglass reinforced plastics, three other types were developed and tested: gravel-water, ground-tube, and aquifer heat storage tanks. For each of these four heat storage concepts there exists at least one prototype installation. With regards to the integration of the solar heating system, one differentiates between short-term and long-term heat storage tanks. The first are designed to cover 15 to 20% of the total space and potable water heating needs by solar means. Systems with long-term heat storage tanks are typically designed to cover from 30 to 60% of these needs.

Text and illustration: BINE Information Service (BINE Informationsdienst), Subject Information Center Karlsruhe, Germany (Fachinformationszentrum),

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