Experimental investigation into cascade thermochemical energy storage system using SrCl2-cement and zeolite-13X materials

Abstract

Significant improvements can be made to thermochemical energy storage system, through heat transfer and thermodynamics analysis. A cascade thermochemical energy storage system has been theoretically shown to improve thermal and exergy energy efficiencies. In this work, an open, cascade system using zeolite 13X and SrCl2-cement composite material is investigated in a lab-scale reactor and compared to the traditional single material systems. The two materials were chosen based on their respective hydration and dehydration requirements. The volumetric energy density ranged from 108–138 kWh m−3 with dehydration temperatures of 50–130 °C and hydration conditions of 12 °C, 75% RH. The thermal and exergy efficiencies were analysed for each system. It was found that the cascaded system improves power output and temperature lift. Furthermore, the cascade system improved exergy efficiency by 6–38% when compared to a traditional salt-based system. This research demonstrates how a cascade thermochemical energy storage system can be cost-effective whilst still maintaining high energy density, power output and temperature lift over a range of dehydration temperatures.