Experimental investigation of SrBr₂·6H₂O-based composite thermochemical material for low-temperature thermochemical heat storage

Thermochemical energy storage (TCS) represents one of the three thermal energy storage (TES) technologies, alongside sensible heat and latent heat storage. TCS has the highest energy density among these TES technologies, with nearly zero heat loss during storage. However, TCS remains relatively underdeveloped, with an overall low Technology Readiness Level of 1-3. The main challenges include limited cycle lifespan and low controllability of the charging/discharging kinetics. We report a study on SrBr 2 ·6H 2 O-based thermochemical materials, particularly their thermal cyclability and kinetics of dehydration (charging) and hydration (discharging) processes of the materials. The results show that the dehydration could be completed within 100 min when the temperature is over 70 °C. The hydration process was found to work well at 18-50% RH, indicating that the SrBr 2 ·6H 2 O pair has a fairly wide range of operating conditions. The hydration of the SrBr 2 ·6H 2 O pair can be finished within 2 hours. Additionally, the performance of SrBr 2 ·6H 2 O-based composite thermochemical materials was studied in a packed bed reactor and the results show that the outlet temperature could achieve 50 °C, with the highest temperature lift of ~35 °C. This suggests that the SrBr 2 ·6H 2 O-based composite material could find applications in hot water supply and space heating.