Experiments on a novel metal hydride cartridge for hydrogen storage and low temperature thermal storage

Abstract

Even though metal hydrides have been mainly studied for hydrogen storage, their applications can be extended to thermal energy storage by utilizing the exothermic and endothermic reactions during the hydride formation and decomposition processes, respectively. In this paper, a low temperature hydride, La0.75Ce0.25Ni5 is experimentally investigated for hydrogen storage and thermal energy storage applications. Heat and mass transfer characteristics of a novel scalable cartridge type reactor is studied at various heat transfer fluid temperatures and hydrogen supply pressures. Maximum hydrogen storage capacity of 1.38 wt% and a gravimetric thermal energy storage capacity of 127.01 kJ.kgMH-1 at about 70% efficiency were achieved. The energy storage capacity achieved during experiments is compared with the theoretically possible output by defining a performance index, namely, the energy storage effectiveness, and its maximum value was found to be 0.67 at 20 °C and 20 bar.