Thermochemical energy storage system development utilising limestone

For renewable energy sources to replace fossil fuels, large scale storage is required and thermal batteries have been identified as a commercially viable option. In this study, 3.2 kg prototype (0.82 kWhth) of the limestone-based CaCO3-Al2O3 (16.7 wt%) thermochemical system was investigated near 900 °C in three different configurations: (i) CaCO3 thermally cycled between 850 during carbonation 950 calcination whilst activated carbon utilised CO2 gas material. (ii) The temperature kept constant at while utilising method drive reaction. (iii) A mechanical compressor used compress into volumetric bottles achieve significant under/overpressure upon calcination/carbonation, i.e. ≤ 0.8 bar > 5 bar, respectively, compared ∼1 thermodynamic equilibrium pressure °C. Scenarios showed 64% capacity retention end 10th cycle. decrease partly assigned formation mayenite, Ca12Al14O33, thus absence beneficial properties expected Ca5Al6O14 sintering also observed. 316L stainless-steel reactor regards corrosion issues after being under atmosphere above for approximately 1400 h, no degradation. This study illustrates potential industrial up catalysed battery provides alternative calcium-looping process.