Tests on a metal hydride based thermal energy storage system

In this paper, the performance tests on Mg + 30% MmNi4 based thermal energy storage device is presented. Experiments were carried out at different supply pressures (10–30 bar) and absorption temperatures (120–150 °C). The effects of hydrogen supply pressure and absorption temperature on the amount of hydrogen/heat stored and thermal energy storage coefficient are presented. The maximum hydrogen storage capacity of 2.5wt% is reported at the operating conditions of 20 bar supply pressure and 150 °C absorption temperature. For a given absorption temperature of 150 °C, the thermal energy storage coefficient is found to increase from 0.5 at 10 bar to 0.74 at 30 bar supply pressure. For the given operating conditions of 20 bar supply pressure and 150 °C absorption temperature, the maximum amount of heat stored is about 0.714 MJ/kg and the corresponding thermal energy storage coefficient is 0.74.

► We demonstrated the feasibility of storing heat using metal hydrides.
► Reported maximum hydrogen storage capacity is 2.5 wt%.
► Reported maximum heat storage capacity is 0.71 MJ/kg of alloy.
► Effects operating parameters on the system performances are investigated.