Thermal Management\nin Hydrogen Storage Tanks Using\nMetal Hydrides and Phase Change Materials

Metal hydrides (MHs) are regarded as highly desirable\nsubstances\nfor both fixed and mobile hydrogen storage applications. Given that\nthe hydrogenation and dehydrogenation of metal hydrides are exothermic\nand endothermic processes that involve substantial heat exchange,\nprecise temperature control is essential. Various methods, including\nthe use of phase change materials (PCMs), have been employed to manage\nthis thermal behavior effectively. In this study, sodium nitrate (NaNO<sub>3</sub>) was utilized in different geometric configurations to store\nthe heat generated during the reaction of Mg<sub>2</sub>Ni with hydrogen.\nComputational fluid dynamics (CFD) methods were used to conduct the\nstudy. Therefore, three distinct geometries were designed to evaluate\nthe performance of PCM and MH beds to reduce the bed temperature and\nenhance the reacted concentration of hydrogen within the bed. By increasing\nPCM-to-MH volume percent from 1 to 18 during absorption, the bed temperature\ndecreases from 627 to 620 K for Case B and 590 K for Case C within\n10,000 s. In addition, the maximum reacted hydrogen for three cases\n(A, B, and C) are 0.12, 0.8, and 1, respectively. Finally, the desorption\nprocess was performed using NaNO<sub>3</sub> and the reacted concentration\nin cases A, B, and C became 0.17, 1 and 1, respectively.