CYCLIC HEAT-TRANSFER IN A NOVEL STORAGE UNIT OF MULTIPLE PHASE-CHANGEMATERIALS

A novel storage unit of multiple phase change materials (PCMs) is deve loped. The physical module consists of a tube which is surrounded by a n external coaxial cylinder made up of several segments of different P CMs with different melting points. A heat transfer fluid flows through the tube to store-extract thermal energy from the PCMs. A finite elem ent model has been developed to simulate the cyclic thermal process in volved as a result of alternating melting and freezing processes. Comp utations have been carried out for the case of high-temperature therma l storage to investigate the advantages of using multiple PCMs over a single PCM in the module. Numerical results indicate that the heat tra nsfer rates can be greatly enhanced using multiple PCMs as compared wi th a single PCM. The enhancement of the heat transfer rate is of pract ical significance to improve the performance of latent thermal storage exchangers. Copyright (C) 1996 Elsevier Science Ltd