Computational study of metal hydride cooling system

A computational study of a metal hydride cooling system working with MmNi_4.6Al_0.4/MmNi_4.6Fe_0.4 hydride pair is presented. The unsteady, two-dimensional mathematical model in an annular cylindrical configuration is solved numerically for predicting the time dependent conjugate heat and mass transfer characteristics between coupled reactors. The system of equations is solved by the fully implicit finite volume method (FVM). The effects of constant and variable wall temperature boundary conditions on the reaction bed temperature distribution, hydrogen concentration, and equilibrium pressures of the reactors are investigated. A dynamic correlation of the pressure–concentration–temperature plot is presented. At the given operating temperatures of 363/298/278 K (T_H/T_M/T_C), the cycle time for the constant and variable wall temperature boundary conditions of a single-stage and single-effect metal  hydride system are found to be 1470.0 s and 1765.6 s, respectively. The computational results are compared with the experimental data reported in the literature for LaNi_4.61Mn_0.26Al_0.13/La_0.6Y_0.4Ni_4.8Mn_0.2 hydride pair and a good agreement between the two was observed.