Seasonal storage of solar thermal energy using supercooled phase change materials (PCMs) is a promising approach for decarbonizing heating. Erythritol, a sustainable PCM, is stabilized in its supercooled state by adding carrageenan (CG), a bio-derived thickener. This composite PCM maintains a stable supercooled state below -30 °C, preventing accidental heat release. Ultrasonication effectively triggers heat release, demonstrating its potential for high-performance, eco-friendly seasonal solar energy storage.
