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Title:
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Material Research on Salt Hydrates for Seasonal Heat Storage Application in a Residential Environment
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Author(s):
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Published by:
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Publication date:
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ECN
Biomass & Energy Efficiency
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18-9-2013
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ECN report number:
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Document type:
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ECN-M--13-022
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Conference Paper
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Number of pages:
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Full text:
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7
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Download PDF
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Abstract:
Water vapor sorption in salt hydrates is a promising method to realize seasonal solar heat storage in the residential sector. Several materials already showed promising performance for this application. However, the stability of these materials needs to be improved for long term (30 year) application in seasonal solar heat storages. The purpose of this article is to identify the influence of the material properties of the salt hydrates on the performance and the reaction kinetics of the sorption process. The experimental investigation presented in this article shows that the two salt hydrates Li2SO4•H2O and CuSO4•5H2O can store and release heat under the operating conditions of a seasonal solar heat storage in a fully reversible way. However, these two materials show differences in terms of energy density and reaction kinetics. Li2SO4•H2O can release heat with an energy density of around 0.80 GJ/m3 within 4 hours of rehydration at 25°C, while CuSO4•5H2O needs around 130 hours at the same temperature to be fully rehydrated and reaches an energy density of 1.85 GJ/m3. Since the two salts are dehydrated and hydrated under the same conditions, this difference in behavior is directly related to the intrinsic properties of the materials.
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