The development of the heat pipe working temperature with the state of charge of the storage unit is very similar for all three cases with deviations up to + 39 K and 19 K from the LiF-phase change temperature, for the insolation and eclipse periods, respectively. The intermediate common heat pipe frequently suggested for an equidistribution of the solar heat to all heat pipes and storage units should be avoided because it may reduce the Stirling efficiency by ca. 5% (abs.). Efforts to increase the heat transfer coefficient to the working fluid of the Stirling engine appear very worthwhile because they may increase the Stirling efficiency by up to ca. 5% (abs.). The desired heat flows are essentially feasible with the HPSE. Deviations from the desired heat flows may be eliminated by acceptable adjustments of the mean temperature of the working gas in the Stirling heater tubes. These predictions will be useful in determining the overall heat balance of a spacecraft with a solar dynamic power system using a Stirling engine. They may easily be extended to a power system with a gas turbine. REFERENCES [1] Strumpf, H. J. & Coombs, M. G. (1987) Advanced heat receiver conceptual design study, NASA CR-180901. [2] Tanaka, K., Abe, Y., Kanari, K. & Kamimoto, M. (1989) ISES Conf., Cobe, Japan. [3] Lindner, F. & Stahle, H. J. (1990) TEXUS experiment on LiF in a graphite capsule, as yet unpublished. [4] Tanaka, K., Abe, Y., Takahashi, Y. & Kamimoto, M. (1988) Latent thermal storage for space solar dynamic power system, Proc. 23 rd IECEC, Denver, CO, USA, July 31 - Aug. 5, 1988. [5] Keddy, E., Sena, J. T. & Merrigan, M. (1988) Transient performance evaluation of an integrated heat pipe - thermal storage system, Proc. 23rd IECEC, Denver, CO, USA, July 31 - Aug. 5, 1988. [6] Fujiwara, M„ Sano, T., Suzuki, K. & Watanabe, S. (1990) Thermal analysis and fundamental tests on a heat pipe receiver for a solar dynamic space power system, J. Solar Energy Engineering, Aug. 1990, Vol, 112/177. [7] Lindner, F., Stahle, H. J. & Tattermusch, P. (1990) Warmespeicher mit Expansionausnehmungen, Patent DE - PS - 39.05.706. [8] Stahle, H. J. & Lindner, F. (1989) Development of a high temperature storage unit for integration with solar dynamic systems, Proc. European Space Power Conference, Madrid, Spain, Oct. [9] Darooka, D.K. (1988) Conceptual designs and integration of Stirling engines in space power systems, Proc. 23rd IECEC, Denver, CO, USA, July 31 - Aug. 5.
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