Rocketdyne has been studying the use of phase change materials (PCMs) for storage of thermal energy for space power systems during the eclipse portion of orbit. The phase change materials are typically contained in metal canisters, and a heat transfer fluid is used to transfer thermal energy in and out of the canisters. The major limitation to heat transfer is the thermal conductivity of the PCM. Incomplete freezing or melting can occur due to this limitation, and as much as 25 % of the PCM may be underutilized. To improve heat conduction to the PCM, heat transfer enhancement designs were made and analyzed by a finite difference technique. Radial fins of 0.25- and 0.51-mm thickness were recommended from this analysis. In this design, the fins were stacked on a central rod at a spacing of 2.5 mm. The heat transfer enhancement designs were tested in 25.4-mm OD, 1.3-mm wall cylindrical tube calorimeters, which were filled with the fin material and phase change material. Simple copper bar fins and a coiled copper screen improved the overall heat transfer by up to 110 % in pure LiOH. Nickel fins of 0.25- and 0.51-mm thickness improved the heat transfer by up to 160 % in 80.5 mole % LiF-19.5 mole % CaF2. The use of internal structure can significantly improve heat transfer, and this option should be considered in the overall design to minimize system mass.


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    Title :

    Tests of heat transfer enhancement for thermal energy storage canisters


    Additional title:

    Versuche ueber die Verstaerkung des Waermeuebergangs von Speicherbehaeltern fuer thermische Energie


    Contributors:
    Gay, R.L. (author) / Pidcoke, L.H. (author) / Munaim, A.I. (author) / Springer, T.H. (author)


    Publication date :

    1988


    Size :

    6 Seiten, 8 Bilder, 3 Tabellen, 1 Quelle


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English