Seasonal solar thermal energy storage using compressor-assisted thermochemical sorption for domestic space heating applications

Due to the unreliability and intermittent nature of solar radiation, using seasonal solar thermal energy storage is necessary to maximise solar energy exploitation. Among different types of seasonal solar thermal energy storage technologies, thermochemical sorption technology has gained increasing attention due to its high energy density along with the negligible heat loss in long-term storage. This study investigates a novel compressor-assisted thermochemical sorption energy storage (CATSES) system using strontium chloride–ammonia (SrCl₂/NH₃) integrated with flat-plate solar collectors (FPSC) to supply domestic space heating. This study develops a dynamic model using real weather data from Newcastle, UK, to evaluate charging in summer and discharging in winter across a range of dwellings with annual heating demands from 3145 kWh to 15,717 kWh, and for both low- and high-temperature heating systems. Results show that using two compressors with 30 m² of solar collectors increases stored solar heat nearly fourfold, from 1153 kWh to 4545 kWh, raising storage efficiency from 39.5 % to 76.3 % with only 434 kWh of electricity input. During winter, the system can fully cover the 6917 kWh heating demand of an energy-efficient dwelling with low-temperature heating, and supply up to 53 % of the 15,717 kWh demand of an inefficient dwelling. The study shows that low-temperature systems allow more effective use of stored heat and solar input, while compressor integration delivers a greater enhancement to storage capacity than increasing collector area. By evaluating system behaviour under real weather conditions and diverse heating demands, the work provides new insights into how CATSES-FPSC can transform low-carbon summer electricity into reliable winter heating, with performance shaped by building efficiency, heating system type, and compressor operation.