Tian, Yuan, Zhao, Chang-Ying and Lapkin, Alexei (2012) Exergy optimisation for cascaded thermal storage. In: 12th International Conference on Energy Storage (InnoStock 2012), Lleida, Spain, 16-19 May 2012. Published in: Proceedings of the 12th International Conference on Energy Storage

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Abstract

Cascaded thermal storage, consisting of multiple Phase Change Materials (PCMs) with different melting temperatures, has been proposed to solve the problem of poor heat transfer caused by unavoidable decrease of temperature differences during heat exchange process. This paper conducts a theoretical study of the overall thermal performance for a cascaded thermal storage system. Both heat transfer rate and exergy efficiency are taken into account. The main findings are: the cascaded arrangement of PCMs enhances the heat transfer rate by up to 30%, whilst it does not always improve the exergy efficiency (-15 to +30%). Enhanced heat transfer and reduced exergy efficiency can both be attributed to the larger temperature differences caused by the cascaded arrangement. A new parameter hex (exergy transfer rate) has been proposed to measure the overall thermal performance. It is defined as the product of heat transfer rate and exergy efficiency, representing the transfer rate of the utilisable thermal energy. The simulation results indicate that the cascaded thermal storage has higher overall thermal performance than the single-staged storage despite of higher exergy efficiency loss.

Item Type:	Conference Item (Paper)
Subjects:	T Technology > TJ Mechanical engineering and machinery
Divisions:	Faculty of Science > Engineering
Library of Congress Subject Headings (LCSH):	Heat storage -- Design, Heat -- Transmission
Journal or Publication Title:	Proceedings of the 12th International Conference on Energy Storage
Publisher:	International Institute for Sustainable Development (IISD)
Date:	May 2012
Status:	Not Peer Reviewed
Access rights to Published version:	Restricted or Subscription Access
Funder:	Engineering and Physical Sciences Research Council (EPSRC), Guo jia zi ran ke xue ji jin wei yuan hui (China) [National Natural Science Foundation of China] (NSFC)
Grant number:	EP/F061439/1 (EPSRC), 51176110 (NSFC)
Conference Paper Type:	Paper
Title of Event:	12th International Conference on Energy Storage (InnoStock 2012)
Type of Event:	Conference
Location of Event:	Lleida, Spain
Date(s) of Event:	16-19 May 2012
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URI:	http://wrap.warwick.ac.uk/id/eprint/49188

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