A new concept for thermal energy storage involves a material that absorbs heat as it melts and releases it as it resolidifies — but only when triggered by light.
A good way to store thermal energy is by using a phase-change material (PCM) such as wax. Heat up a solid piece of wax, and it’ll gradually get warmer — until it begins to melt.
PCMs are now used in applications such as solar concentrators, building heating systems, and solar cookers for remote regions.
Jeffrey Grossman - Professor
MIT - Know more