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Title:
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Storage and transformation of waste heat
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Author(s):
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Published by:
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Publication date:
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ECN
Energy Efficiency in Industry
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1-11-1999
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ECN report number:
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Document type:
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ECN-RX--99-037
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Article (scientific)
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Number of pages:
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13
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Published in: Contribution to the 4th IAE-Annex 10 workshop, Phase Change Materials and Chemical Reactions for Energy Storage, October 28-29, (), , , Vol., p.-.
Abstract:
In a recently finished project the storage of heat in a cheap andflexible water bag in combination with different kinds of heat generation
options like solar collectors, heat pumps, co-generation and district heating
have been investigated. Model studies showed that energy savings up to about
15% are possible. In a test system consisting of a thermally insulated,
flexible 7 m3 water bag, a heat generating and a heat-destroying unit,
measurements have been performed in order to confirm the calculated savings.
Upgraded low quality heat can very well be used for both heating and cooling
purposes. Upgrading can take place using a so-called chemical heat pump (CHP)
with inherent storage possibilities, operating in a continuous or batch-wise
mode. Reversible decomposition reactions of organic or inorganic substances
are used to achieve the required temperature lift. An advantage of the CHP is
that temperature lifts can be larger than 100 deg C. Systems studies and an
economical analysis showed that CHPs with reactions like isopropanol <->
acetone hydrogen using a distillation column for separation after the
dehydrogenation reaction will become too expensive to be applied in industry.
The development of the SWEAT (Salt-Water Energy Accumulation and
Transformation) system is a project directed to cooling applications (5-15
deg C) in industry and air-conditioning in commercial buildings and the
automotive sector using waste heat at about 80 deg C. This system uses the
dehydration/hydration of Na2S. An inherent advantage is the storage of
energy (cold or heat) after regeneration of the system. The current R and D
are directed to corrosion protection, the design of the evaporator and the
feasibility of using other solid/vapour pairs for different temperature
windows
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