Metal hydrides for thermochemical energy storage applications

Abstract

Due to the depletion of natural energy resources, worldwide, solar energy is accepted as an emerging energy source because it is free, endless and can be convertible to other forms, but it is intermittent. Therefore, in the present study, different energy storage techniques, that is, sensible heat, latent heat and thermochemical heat storage techniques, suitable to store solar thermal energy are discussed and compared. Based on the energy storage density, reaction kinetics, operating temperature range and volume of storage material, the metal hydridebased thermal energy storage (MH-TES) system is observed to be the most promising for thermochemical energy storage applications. In continuation, the current work enlightens on the screening of MHs best-suited to the MH-TES, which results in the alloy pairs of MmNi 4.15 Fe 0.85 -TiCrMn and LaNi 4.85 Al 0.15 -MmNi 4.6 Fe 0.4 , working on high-pressure and low-pressure sides, respectively. The thermodynamic performances are observed to be 140.25 and 188.16 kJ of heat generation with a coefficient of performance of 0.47 and 0.50 for MmNi 4.15 Fe 0.85 -TiCrMn and LaNi 4.85 Al 0.15 -MmNi 4.6Fe 0.4 pairs, respectively, working at a temperature range of 403 (storage), 298 (ambient), 373 (regeneration) and 423 K (heat output). The study is extended to investigate the influence of operating temperatures on system performance and observed that the heat generation may be reduced by~5% by increasing heat output temperature by 20 K due to reduction in mass transfer.

Impacts, Barriers, and Future Prospective of Metal Hydride‐Based Thermochemical Energy Storage System for High‐Temperature Applications: A Comprehensive Review

“…Metal hydrides (MHs) have been used in several thermal applications such as cooling, heating, hydrogen compression, and so on, discussed in review articles. [13][14][15][16] Review articles based on MH-based TES applications have focused majorly on Mg-based metal alloys. Some of them also reviewed low-temperature MHs (LTMHs) such as alanates and borohydrides.…”

A Review on Energy Storage Technologies: Current Trends and Future Opportunities

“…This charged material releases heat during the discharging process, enabling applications such as water heating, space heating, and power generation. Thermochemical materials (TCMs) like salt hydrates [33,34], metal hydroxides [35,36], carbonates, zeolites [37,38], metal organic frameworks [39], metal oxides [40], metal hydrides [41][42][43][44] and composites [45,46] exhibit diverse reactions. TCMs offer a significantly higher energy storage density, approximately 8 to 10 times greater than sensible energy storage and twice that of phase change materials (PCMs) [47].…”

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

“…Apart from this, the selection of alloy also depends on its thermodynamic properties (i.e., reaction enthalpy and entropy), operating temperatures, and pressures. It is also observed that many studies have been carried out on single-stage TCESs, including the authors' previous studies, [3,7,21] in which several metal hydride pairs were tested to identify their suitability for TCES at different operating conditions. Though many studies are available on single-stage TCESs, the study can be extended further for multistaging to achieve higher efficiency.…”