REDOX AND FLUIDIZATION PERFORMANCES OF CO3O4/CoO FOR SOLAR THERMOCHEMICAL ENERGY STORAGE

Thermochemical energy storage using redox pair of Co3O4/CoO powders was studied for thermal energy storage (TES) using concentrated solar radiation as the energy source. Reversible chemical reactions (reduction -oxidation redox cycles) of oxides under air atmosphere are used to storage significant thermal energy via the enthalpies of the chemical reactions at high-temperature. A promising concept for solar TES is proposed using fluidized bed with Co3O4/CoO redox pair. In the present study, the effects of particles size of Co3O4/CoO powders on thermochemical storage performances are investigated in order to explore the potential of the material for fluidized-particle bed reactor. The Co3O4 powders with particle sizes of 100-200, 200-300, 300-500 and 500-700 jum were used to test redox performances by thermo-gravimetric analysis. A flowability (fluidization state) of Co3O4 powders in a fluidized bed reactor for thermochemical energy storage is also examined in this study. A basic relationship between pressure drop of inlet gas and gas flow rate was experimentally examined using bed materials with different particle sizes by a small-scale quartz reactor at ambient pressure and temperature.