Development of a Two‐Stage Hydrogen‐Based Thermochemical Energy Storage System

Both energy conservation and the use of renewable resources are necessary due to the global increase in energy demand. A useful technique for energy storage, when renewable energy sources are available, is a thermochemical energy storage system that relies on the interaction of gases with solids. From this vantage point, hydrogen offers a sustainable and regenerative response to this pressing issue. In line with that, herein, the operation of a novel two‐stage hydrogen‐based thermochemical energy storage system (TS‐H‐TCES) is proposed to attain a higher energy density and is analyzed with the help of the thermodynamic cycle. The proposed system operates at 298, 373, 403, and 423 K as atmospheric temperature ( T atm ), waste heat input temperature ( T m ), storage temperature ( T s ), and upgraded/enhanced heat output temperature ( T h ), respectively. For the given operating temperature, the thermodynamic performance of TS‐H‐TCES is evaluated using experimentally measured pressure–concentration isotherms of LaNi 4.7 Al 0.3 , LaNi 4.6 Al 0.4 , and MmNi 4.6 Al 0.4 . The maximum coefficient of performance, second law efficiency ( η II ), and thermal energy storage density are found to be 0.67, 0.70, and 220.98 kJ kg −1 , respectively. The impact of operating temperatures on system performance is also investigated, which is important in choosing the best temperature range for a certain application.