Abstract
Chemical heat storage has been researched as a method for utilization of low temperature heat under 150℃ In this study, focus on hydrated Na_2S (Sodium sulfide) for its high heat storage density (308 kJ/mol). We describe examining analysis method, and how shorten time of hydration/dehydration. Through this study, we got the conclusion that composite material makes dehydration time shorten for its high thermal conductivity. However, since hydration is influenced by mass transfer, the composite method does not make hydration time shorten. Consideration for method for shortening hydration time is needed.