Researchers from India’s National Institute of Technology (NIT) Kurukshetra and the National Institute of Solar Energy (NISE) have developed an innovative solar geyser system utilizing fine sand as a thermal energy storage medium. This fine sand solar geyser (FSG) system effectively addresses the common issue of solar energy intermittency, resulting in an impressive energy cost of just $0.0233 per kilowatt-hour. It features a photovoltaic integration with solar panels, a nichrome wire heating rod for heat conversion, and a circular heat exchanger that efficiently transfers the stored thermal energy to water. In initial tests, the system demonstrated remarkable performance, achieving significant temperature increases in the sand, from approximately 25.2°C to 164.2°C over two days, and maintaining high discharging efficiencies of around 90%.
The economic viability of the FSG system is also noteworthy, as it presents a favorable techno-economic analysis with a payback period of just 4.45 years and an impressive operational lifespan of 25 years. The system has shown its capacity to deliver substantial quantities of hot water, providing 140 to 152 liters in practical demonstrations. With the ability to operate effectively even during low solar radiation or nighttime, the sand-based solar geyser holds significant potential for affordable and sustainable domestic water heating solutions, thereby making strides towards eco-friendly and cost-effective energy alternatives.