Supercooled sodium acetate aqueous solution for long-term heat storage to support heating decarbonisation

Heating decarbonisation through electrification requires the development of novel heat batteries. They should be suitable for specific application and match operation conditions domestic renewable energy sources. Supercooled liquids, often considered a drawback phase change materials, are among most promising technologies supporting heating decarbonisation. Although some studies have shed light on stable supercooling, fundamentals stability remain open problems not always accompanied by relevant experimental investigations. This research critically analyses physic chemistry sodium acetate (SA, NaCH3COO) aqueous solution, low-cost, non-toxic, abundant compound with supercooling long-term storage. It has an appropriate temperature high-density storage using pumps or solar thermal in residential applications. The existing discrepancies literature discussed systematic evaluation, providing insights into efficient material design boundary reliable use Despite previous showing that reliability solution as supercooled liquid cannot guaranteed, this study demonstrates encapsulation sealing method, peritectic composition (p-SA 58 wt%) can used melting 57 °C, technologies. is demonstrated efficiency maintained under cycling, constant latent capacity 245 kJ/kg volumetric density 314 MJ/m3. was confirmed achieve fully-melted state supercooling. Finally, local cooling retaining seed crystals high pressure were highlighted basic principles successful crystallization release. store long periods without losses due to its subcooling. Latent released when required at any selected time just simple activation process.