Thermochemical Heat Storage for Homes: A Strontium Bromide Seasonal Store Designed From First Principles

A household thermochemical heat store using strontium bromide is designed from first principles: summer solar heat at 88 C drives water out of the hydrated salt, and in winter the water is evaporated back and the heat of hydration heats the house. A system with 3,500 kg of salt stores 795.0 kWh usable in 8.16 cubic metres (97.4 kWh per cubic metre at full system level), retains 0.996 of its charge over four months, and delivers 779.8 kWh at a rated 3.5 kW. It beats a seasonal water tank on volume (8.16 against 26.4 cubic metres) and standing loss (0.4% against 49.1%), but the salt costs $39.62 per kWh of capacity and seasonal delivered heat costs $4.93 per kWh, against $0.92 per kWh for the water tank and $0.166 per kWh for a heat pump. SIMULATED, NOT MEASURED: nothing was built or hardware-tested.