From the vibrant heart of India emerges an inspiring tale of three remarkable teenage inventors dedicated to enhancing rural healthcare. Their journey began with a vision to create a portable refrigerator that operates without electricity or coolant fluids, a truly innovative solution for communities in need.

Introducing the Thermavault—a compact, salt-cooled fridge that cools passively as salt dissolves in water. This ingenious design eliminates the need for power outlets or batteries, making it a game-changer for storing essential medical supplies.

These enterprising teens, Dhruv Chaudhary, Mithran Ladhania, and Mridul Jain, are motivated by their backgrounds as children of medical professionals in Indore. Witnessing the challenges of keeping COVID-19 vaccines viable while traveling to remote villages in the sweltering heat inspired them to develop a reliable solution.

The magic of the Thermavault lies in the way it utilizes salt molecules, which absorb heat from water as they dissolve, resulting in a cooling effect. The team embarked on an exciting quest to discover the best salt combinations for optimal performance. While they explored numerous possibilities online, they ultimately found their answers in the pages of their ninth-grade science textbooks.

Their persistence paid off when they partnered with professors at the Indian Institutes of Technology, who helped them identify two effective salts: barium hydroxide octahydrate and ammonium chloride. These salts work beautifully together, allowing the Thermavault to maintain temperatures ideal for various vaccines—cooling them to between 2 and 6 degrees Celsius, and even below freezing when needed.

In testing, Dr. Pritesh Vyas, an orthopedic surgeon in Indore, shared the excitement of their success. The Thermavault has proven capable of preserving vaccines for an impressive 10 to 12 hours, a significant advancement for rural healthcare.

The team is already hard at work, designing prototypes and preparing to test 200 units across 120 hospitals in Indore. Their ingenuity and commitment to improving healthcare have not gone unnoticed; they received the prestigious 2025 Earth Prize, which includes a generous $12,500 to support their testing phase.

This remarkable invention embodies the spirit of innovation and the power of young minds making a difference in the world. The Thermavault is not just a fridge; it represents hope, progress, and a brighter future for healthcare accessibility.