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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

THE RATE PROBLEM IN SOLID-LIQUID PHASE CHANGE HEAT TRANSFER: EFFORTS AND QUESTIONS TOWARD HEAT EXCHANGER DESIGN RULES

Get access (open in a dialog) DOI: 10.1615/IHTC16.kn.000023
pages 425-440

要約

The use of phase change materials (PCMs) in energetic systems today is in large parts restricted by dynamic issues, or what could be termed the "rate problem"; i.e. how long will it take (heat transfer rate) to store, or recover, a given amount of thermal energy in a latent heat energy storage system (LHESS) for a specific application? There is no theory today that can easily answer that question. Therefore, this keynote paper focus on the work done currently in the PCM heat transfer community to better understand heat transfer within PCM-based thermal storage systems (TES), the study of application specific designs of PCM-TES, and the search for a theory to guide the design of those systems from a heat exchange point of view. To that affect, the study of a large number of different PCM-heat exchanger configurations is required to achieve the important long-term objective of determining heat exchanger design rules. For some decades now, numerous configurations of PCM-heat exchangers have been designed, built and studied; and important results and lessons from these studies will be presented and discussed. Furthermore, through the sum of all those results, the search for a PCM-heat exchanger's design theory is on-going. This theory could follow traditional ε − NTU or LMTD methods, as some researchers have already tried, or require novel approaches. Fundamental questions are still unanswered: what are the important parameters for such theory? What are and how should the dimensionless numbers needed be defined? What reference temperature needs to be used for the PCM? This paper will ask many more questions and try to provide paths to determine some of the answers.