Blueprint: Strontium Bromide Thermochemical Seasonal Heat Store — Design and Failed Cost Test (from DOI 10.5281/zenodo.24109015)

DESIGN BLUEPRINT — SIMULATED, NOT MEASURED — NOT BUILT. This blueprint package publishes the strontium bromide thermochemical seasonal store of DOI 10.5281/zenodo.24109015 together with its failed economics at full size, so the licence record shows both. The design: 3,500 kg of strontium bromide in a 3.04 m3 packed bed inside a steel reactor 1.6 m in diameter and 1.64 m high, a 1.25 m3 water reservoir holding the 1,064 kg of water driven off on charging, 0.20 m of mineral insulation, and auxiliary evaporator, fan and ducts; total system 8.16 m3 and 4,040 kg, holding 935.2 kWh gross and 795.0 kWh usable at 97.4 kWh per m3 system level, retaining 0.996 of its charge over four months, and delivering 779.8 kWh after the stand. Charging needs 88 C, reached by a 12.0 m2 evacuated-tube array at 0.601 efficiency in 23.8 days (flat plate 0.43, 33.3 days). Discharge is rated 3.5 kW, covers the stated house's 2.52 kW average winter load but not its 4.2 kW peak, and one charge is 7.1 percent of annual demand. THE FAILED COST TEST, AT FULL SIZE: salt at $9 per kg costs $39.62 per kWh of usable capacity, total capital is $45,800, and heat delivered in seasonal use costs $4.93 per kWh — about thirty times a heat pump's $0.166 per kWh and more than five times a seasonal water tank's $0.92 per kWh. On present material prices, for a grid-connected house, the correct decision in the source is the heat pump. The package gives a bill of materials at component-class level, sizing rules, construction sequence, commissioning tests, operating limits, degradation figures, and failure modes. Nothing was built or tested.