The system is described by its creators as a cost-effective solution for water heating by storing thermal energy in fine sand. Techno-economic analysis indicated the system is economically viable for domestic water heating applications, with an initial capital cost of $278 and an expected lifespan of 25 years…
https://www.pv-magazine.com/2025/05/30/indian-scientists-design-pv-powered-fine-sand-solar-geyser/
