The reversible thermochemical reaction between magnesium hydroxide and magnesium oxide is recommended for storing heat energy in the middle temperature range of 300-500 oC. However, the low hydration rate of magnesium oxide limits the heat storage performance for practical applications. In this study, the nano-porous carbon supported composite was prepared by calcination method for improving the heat storage performance. The hydration and dehydration experiments were carried out. The results show that the overall heat storage density of composite can be improved to 1053 kJ/kg, which is 1.4 times that of pure material. Compared with other experimental results, the heat storage density of the composite has been improved by more than 30%.
Keywords thermochemical heat storage, hydration, magnesium hydroxide, nano-porous carbon