Fundamental Study on Composite Chemical Heat Storage Materials Composed of MgSO4 and Mesoporous Materials

Abstract

To utilize low-temperature waste heat below 200 oC effectively, this study focused on a chemical heat storage system employing magnesium sulfate (MgSO₄) hydrates. To overcome practical challenges such as particle agglomeration and low hydration rate of MgSO4, we conducted a fundamental study on the composites of MgSO4 hydrate with mesoporous materials. We prepared the composites using MgSO4 and mesoporous silicas or mesoporous carbons (MPCs), and evaluated pore structure, hydration rates, and heat storage densities of the composites. The results demonstrated that the hydration reactions of the composites proceeded significantly faster than that of pure MgSO₄. Notably, the MPC/MgSO₄ composite achieved a heat storage density of 1130 kJ/kg (per unit mass) and 807 kJ/L (per unit packed bed volume) within 1800 seconds of hydration.