Thermochemical Heat Storage Using Strontium Bromide Hexahydrate (SrBr₂·6H₂O): Thermodynamics, Kinetics, and Applications

Abstract

This comprehensive study establishes SrBr₂·6H₂O as a viable thermochemical material through coupled thermodynamic, kinetic, and application analyses. Equilibrium vapor pressure measurements reveal P_eq = 12–200 mbar (25–80°C), with ΔH = 58±2 kJ/mol H₂O for dehydration. Kinetic modeling shows Avrami-Erofeev behavior (n=1.5, k=1.1×10⁻³ s⁻¹ at 80°C for doped samples). In Arctic applications, the material achieves 60% solar fraction in residential heating, with composite engineering (graphite/SiO₂ additives) resolving clumping and corrosion issues. A 340 kg test unit demonstrated 0.9 GJ/m³ usable capacity at 75% round-trip efficiency. The work provides design guidelines for SrBr₂ systems, including: (1) dehydration at 80–100°C with <15 mbar P_H₂O, (2) hydration triggering at 50–70°C with >60% RH, and (3) N₂ blanketing for multi-year stability