In order to elucidate the mechanism of thermal runaway of the solar cell, we created a simulation model consisting of positive feedback due to the temperature characteristics of the shunt spot and negative feedback due to the thermal resistance of the spot, and calculated the temperature distribution of the solar cell. In this paper, we report the simulation results of the shrinkage rate of the shunt spot diameter, the change of the shrinkage rate due to the design change of the solar cell, and the change of the shrinkage rate due to the addition of electrode resistance. Furthermore, we propose design formulas for elucidating the spot diameter stop mechanism.

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If a waste heat of a factory, solar heat etc. can be used effectively, it can contribute to great energy saving and construction of a low carbon society. In this research, we propose the “latent heat thermal energy storage type direct-contact heat exchanger” which combined a latent heat thermal energy storage technology and a direct contact type heat exchange system. We adopted the Mannitol-water mixture as a phase change material. In this heat exchanger, the air is heated by a generation of the air bubble sent in the Mannitol-water mixture. At the same time, the crystal of the Mannitol generated at the air-liquid interface is destroyed by an air bubble and precipitated. Therefore, the heat exchange is performed continuously. This heat exchanger is excellent in cost performance, and can store the energy with high density. In this report, we estimate the possibility of a practical application synthetically.

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