TG-DTAによるNa₂S化学蓄熱材料の水和･脱水反応サイクルの特性評価

抄録

This paper describes the results of using Na₂S･xH₂O hydrate to study the repetitive properties of chemical heat storage cycles. The hydration/dehydration cycle experiments were carried out using TG-DTA with varying dehydration temperature, hydration temperature and water vapor pressure. This hydrate melts in two cases and the repeated reaction could not be obtained. One is when the heating temperature exceeds the melting point during the dehydration process, and the other is the case when the hydration temperature is lower than the melting point which is decreased due to the increase of the hydration number x. According to the experimental results in the dehydration temperature range of 60~100°C, repeated characteristics could not be obtained at the temperature higher than 90°C, and the dehydration reaction did not proceed at 60°C or lower under water vapor pressure of 1.2 kPa. It was clarified that the dehydration reaction temperature is limited to 70~80°C. From the experiments in which the hydration temperature was changed in the range of 25 to 40°C, the results showed that the cycle characteristics were not significantly affected. Although the amount of sample is small, and the number of cycle reactions is 10 to 20, the conditions of dehydration reaction temperature, hydration reaction temperature, and saturated vapor pressure to obtain chemical heat storage cycles were clarified.