Three teenagers in Indore, India, have invented a salt-powered refrigerator that works without electricity—offering a game-changing solution for rural healthcare. Inspired by the challenge of transporting COVID-19 vaccines to off-grid areas, Dhruv Chaudhary, Mithran Ladhania, and Mridul Jain developed “Thermavault,” a cooling system that uses special salts to absorb heat and maintain cold temperatures for up to 12 hours. The innovation recently won the 2025 Earth Prize and $12,500 in funding, which the team plans to use to build 200 units for testing in 120 hospitals.
Their invention uses ammonium chloride and barium hydroxide to create targeted cooling ranges ideal for vaccines and sensitive medical supplies. Reusable and compact, Thermavault eliminates the need for ice or electricity, making it perfect for remote regions. The teens now aim to secure WHO certification and global distribution support. As they prepare to scale their design, the project stands as a powerful reminder of how youth innovation can help solve real-world problems—no power required.