Thermal analysis of exothermic process in a magnesium hydride reactor with porous metals

• Numerical simulation of Mg/MgH2 system with porous metals was carried out.
• Effect of porous metals on heat transfer performance was examined.
• Two major driving forces lead to an optimal bed temperature for the reaction.
• Parametric studies were performed to examine the optimal conditions for output power.
• A sensitivity analysis was performed to evaluate the factors influencing the reaction time.

Compared with sensible and latent heat storage, thermochemical heat storage has the advantages of high storage capacity, low storage loss, etc., which make it become a most promising candidate for heat storage. Among numerous materials used for thermochemical heat storage, magnesium based materials are abundant, inexpensive and have a high storage density, therefore they have attracted extensive investigations. In this paper a two dimensional mathematical model for the heat releasing process of the Mg/MgH2 system was established to study the transient heat and mass transfer process. The results show that the effective heat transfer is the key factor influencing the output power. With the addition of metal foams, the effective thermal conductivity has a significant promotion, and thereby shortening the reaction time and improving the output power. A parametric study was conducted to examine the optimal conditions for the highest output power and a sensitivity analysis was performed to evaluate the various factors influencing the reaction time.