(Courtesy The Earth Prize)
Many people take electricity for granted. But in rural areas around the world, there are no electrical grids to provide power. Now, three teenagers in India have invented a mini-refrigerator that is powered by salt that can be used to help transport medical supplies to rural areas that do not have electricity, reported MSN.
The three teens who all live in Indore, Dhruv Chaudhary, Mithran Ladhania, and Mridul Jain, have parents who work in medical fields. They told MSN that they were inspired to find away to keep medications cold after hearing about how challenging it was to bring Covid19 vaccines to rural areas that did not have electricity.
Their invention, called Thermavault, recently won the teens the 2005 Earth Prize for Asia which comes with a $12,500 prize that the teens plan to use to build 200 salt-powered fridges to send to rural hospitals for testing.
The Earth Prize is the world’s largest environmental competition and ideas incubator for 13-19-year-olds, reported Forbes. It was started by The Earth Foundation in 2021. The foundation was created by Peter McGarry, an Irish hedge fund option trader living in Geneva, Switzerland after he watched a student climate protest.
In 2025, there were seven global winners by region – North America, Africa, Asia, Central and South America, Oceania and Southeast Asia, Europe, and the Middle East – and the winners were announced in April, according to the organization.
The Science Behind the Thermavault
When the teens set out to create a salt-run refrigeration unit, their first obstacle was to find which salt was the most efficient to use. They understood that some salts can have a cooling effect when dissolved in water, according to MSN. That’s because when the salt dissolves, the atoms that it is comprised of break apart using energy from the environment.
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Dhruv, Mithran, and Mridul first did an internet search to find out which salt could work, narrowing it down to 20. They evaluated the salts at a lab at the Indian Institutes of Technology but none of the salts cooled the water enough.
“While we did scour through the entire internet to find the best salt possible, we kind of just ended up back to our ninth-grade science textbook,” Dhruv told MSN.
They found that ammonium chloride could maintain temperatures of around 2 to 6 degrees Celsius (about 35 to 43 degrees Fahrenheit), which would work well for some vaccines. Adding barium hydroxide octahydrate lowered the temperature enough to support transplant organs.
Three months later, the trio built their prototype and began testing it in hospitals.
Meet the Thermavault
The refrigerator itself consists of an insulated plastic container with a copper wall lining where the vaccines or organs will be housed. The dissolved salts cooling solution is poured in between the two. The salt is reusable, so no ice packs are needed.
The tests on the unit have been largely successful. “We have been able to keep the vaccines inside the Thermavault for almost 10 to 12 hours," Dr. Pritesh Vyas, an orthopedic surgeon who tested the device at V One hospital in Indore, says in a video on the Thermavault website.”
He added that with some improvements including a built-in temperature monitor, the fridge can be useful in remote off-the-grid places.
The money from the Earth Prize will help Dhruv, Mithran, and Mridul improve and scale up their invention to help bring medicines to rural communities around the globe.
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