Numerical investigation of two discharging procedures of a metal hydride-hydrogen storage tank

This article presents a numerical investigation of two discharging procedures of a metal hydride-hydrogen storage tank (MH-HST). The former is categorized as "simultaneous procedure" as the heating of the MH-HST and the discharging of hydrogen from the same start simultaneously. The latter is categorized as "separated procedure" as the heating of the MH-HST was carried out initially and the discharging of hydrogen from the same began only when the desired desorption temperature is attained. To the best of authors' knowledge, the separated procedure is simulated and compared for the first time with the simultaneous case. For the two procedures, the discharging process was carried out in two ways, that is, at constant and variable applied pressure. A computational model governing heat and mass transfer within the MH-HST was developed and successfully validated with experimental data. The simulation results ascertain that the simultaneous procedure is faster than the separated procedure. For example, with a desorption pressure of 0.1 bar and a heating fluid temperature of 353 K, the "simultaneous procedure" provides a reduction of the discharging time by 57% in comparison with the "separated procedure."