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 LaNi4.7Al0.3, LaNi4.6Al0.4, and MmNi(4.6)Al(0.4). The maximum coefficient of performance, second law efficiency (eta(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.