Three teenagers from India have won the 2025 Earth Prize for Asia for their unique invention of a mini-refrigerator that uses only salt and not electricity. Their invention, called the Thermavault, will help hospitals in remote areas without access to electricity, to transport medical supplies, such as vaccines and organs.
They used salt as the main cooling material. ammonium chloride and barium hydroxide octahydrate were a mixture of salts that they used to maintain a temperature of 2 to 6 degrees Celsius, perfect for storing vaccines. If lower temperatures are required, it becomes subzero, ideal for transplant organs.
The Thermavault is an insulated plastic container with a copper lining inside. The cooling solution from molten salt is placed between the plastic and copper walls, so even if you don't have electricity, it's still reusable. This is a big help compared to cold boxes and coolant packs that only use ice packs.
They plan to produce 200 Thermavault for 120 hospitals in India and obtain Performance, Quality, and Safety certification from WHO.
