Study on the hydrogenation of an Mm‐based AB5‐intermetallic for sustainable building applications

In the present study, a numerical approach regarding the thermal management of an Mm‐based AB₅‐intermetallic (MmNi_4.6Al_0.4) for the hydrogenation process is introduced and analysed. Several heat management scenarios are studied. The numerical model was supported and validated with experimental data in terms of hydrogenation capacity and temperature distribution. The numerical analysis is based on the introduction of the energy, mass, and momentum conservation equations to numerically describe the hydrogenation reaction. The main aim of the present study is the numerical description of the heat management when 200 g of hydrogen are stored (13 kg of the hydride). The heat management cases consider the usage of cooling tubes in combination with high thermal conductivity fins. In general, various parameters affect the efficiency of the heat management. The parameters considered are the fin thickness, the fin number—which is directly connected to the metal hydride thickness convective heat transfer coefficient. A nondimensional parameter (nondimensional conductance [NDC]) specially modified to describe the role of the fins in addition to the cooling tubes is introduced to evaluate the heat management. The target of the study was to reduce the hydrogenation time of almost 13 kg of MmNi_4.6Al_0.4, and from the parametric study, it has been found that the more efficient conditions are fin thickness between 5 and 8 mm and the convective heat transfer coefficient of 2000 W/m² K.