New salt hydrate composite for low-grade thermal energy storage

This study aims to develop a new salt-based thermochemical composite for long-term storage of low-grade thermal energy which enables overcoming mismatch between energy demand and supply. The energy density and dehydration behaviour of five different salts; Al2(SO4)3·18H2O and MgSO4·7H2O, CaCl2·6H2O, MgCl2·6H2O, and SrCl2·6H2O are examined. Subsequently, the performance of two low cost host porous structures; expanded clay and pumice, impregnated with the most suitable salt for storing low-grade thermal energy is studied over a few number of cycles using a lab-scale packed bed reactor. The results showed that SrCl2·6H2O has the highest energy density and lowest dehydration temperature so that >80% of its energy density can be stored at