Another model storage unit using LiF only had been previously investigated [2,3], and LiF had been confirmed to be a promising material for latent thermal storage units of space solar dynamic power system. However one canister of this model storage unit had been fractured after several cycles of charge and discharge. One of the reasons of the fracture would be thermal stress during melting of the LiF. Some ideas had been requested for avoiding the fractures caused by the thermal stress. One of the problems on using LiF for the latent thermal storage units, i.e. fracture on the canisters by thermal stress due to large volume change of LiF, was confirmed to be solved by using the composites. Figures 17 to 20 show a comparison of outlet temperatures of the working fluid dining the first cycle of the charges and discharge. The calculated results agree well with the experimental results. Designed values are also shown in the figures. The designed values are obtained on assumption that the additional values of thermal resistance, shown in Table 3, do not exist and that the whole of the canister storage space is filled with the composite materials. In these figures, designed values show that variation of the outlet temperature of the working fluid is smaller than 100K, while experimental results show that the variation is larger than 150K. This phenomenon seems to be also caused by the additional thermal resistance and smaller volumes of the composites.
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