58. Thermochemical Heat Storage Using Mn₂O₃/Mn₃O₄ for Next-generation CSP : Cyclability Improvement by Mixing Nanoparticles

Abstract

Thermochemical energy storage (TCES) utilizes the thermal charging/discharging process in a reversible chemical reaction, and is one of the most promising thermal storage technologies. An inexpensive material of Mn₂O₃/Mn₃O₄ system has a suitable storage density in next-generation CSP plant, but suffers from slow kinetics in its discharging process, as well as poor cyclability of the redox reaction in air under atmospheric pressure. To improve the cyclability of Mn₂O₃/Mn₃O₄ system, the authors examined and evaluated a solid mixture of nanoparticles and Mn₂O₃ to suppress their sintering at high temperature. In this study, the authors tried to evaluate and compare two kinds of mixing method. The thermochemical cycle of thermal reduction process (charging step) and subsequent oxidation process was conducted by using thermogravimetric analysis (TGA). The extent of oxidation reaction during the discharging step of multi-cyclic performance assessment was examined.