Method for screening paired metal hydrides with appropriate phase change material for a thermochemical energy storage system

Thermochemical energy storage (TES) systems using coupled metal hydrides (MHs) have long been recognized as an option for sustainable energy systems such as solar power plants. The MHs-TES system consists of two linked MH beds (energy storage bed and hydrogen storage bed) that exchange hydrogen during the heat storage/release cycles. The heat reaction of the hydrogen storage bed is stored in a PCM as latent heat, which is recovered during the heat release step. One of the main issues of the MHs-TES system is selecting the best-suited combination of MHs and compatible PCM to satisfy application requirements. Herein, an approach is proposed for screening the right pairs of hydrides and the suitable PCM. To assess this procedure's effectiveness, a 2D-mathematical model is developed, and a computer code is established. In addition, using this code, the dynamic behavior of the MHsTES system and the effect of the hydrogen storage bed temperature on the system's performance are examined. The Mg2Fe alloy as HTMH bed, and two LTMH beds as LTMH (LaNi4.25Al0.75 at medium temperature and LaNi5 at low temperature) are used. With an efficiency of 86.5%, the results show that Mg2Fe/LaNi5 is a viable MHs combination for a thermal storage system.