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Title:
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Compacte chemische seizoenopslag van zonnewarmte; Eindrapportage
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Author(s):
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Visscher, K.; Veldhuis, J.B.J.; Oonk, H.A.J.; Ekeren, P.J. van; Blok, J.G.
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Published by:
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Publication date:
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ECN
Energy in the Built Environment
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1-8-2004
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ECN report number:
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Document type:
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ECN-C--04-074
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ECN publication
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Number of pages:
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Full text:
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92
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Download PDF
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Abstract:
Compact seasonal storage of solar heatFor a 100% solar heat supply for space heating and tap water heating
in the Northern climates it is a necessity to store energy (heat) for
a period of at least half a year.
In this study candidate materials are searched for reversible thermo
chemical heat storage and heat production in a system concept consisting
of a solar collector, a chemical reactor with heat exchangers and separate
material buffers for the reactants.
On basis of a literature search of materials and their thermodynamic
properties a "realization potential" derived from seven selection criteria
was calculated for each material. The five best scoring candidate materials
have been compared with conventional hot water storage through a system
simulation or a calculation of the heat storage and production process.
The storage of reactant materials was under atmospheric conditions in
all cases.
From the simulations it follows that magnesiumsulphate-heptahydrate
and iron-hydroxide offer the best chances for development of a new autonomous
thermo chemical storage system with an effective energy density that
is one order of magnitude larger than that of hot water storage.
From calculations is follows that silicon dioxide offers a chance for
development of thermo chemical storage system with an effective energy
density that is two orders of magnitude larger than that of hot water
storage. This process is not autonomous because the heat storage part
of the process cannot be conducted near residential buildings. It is
however suitable for central production of the solid silicon fuel from
silicon dioxide on an industrial scale. The high density silicon fuel
then can be transported to residential areas and be "burnt" with oxygen
or nitrogen from the ambient air.
In this study no definite statements could be made about the reaction
rate and material conversion of the reversible chemical reactions. Thermal
analyses of some model materials showed that the chemical reactions
studied usually do not react easily under atmospheric conditions. The
list of best scoring candidate materials therefore has to be considered
as a first selection of materials that deserve further research.
The materials selected follow the required thermodynamic and technical
conditions, but their practical application still has to be demonstrated.
This can pose many practical problems.
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