Three teens from Indore, India, are making a lifesaving impact with a simple but groundbreaking idea. 

As reported by Business Insider, their invention, a mini salt-powered refrigerator called the Thermavault, keeps vaccines and other medical supplies cold without electricity, offering a powerful solution for rural health care systems.

Dhruv Chaudhary, Mithran Ladhania, and Mridul Jain were high school students during the COVID-19 pandemic when they saw firsthand the challenges their health care worker parents faced. One obstacle stood out: How do you keep vaccines cold in places without power?

That question led them to an answer tucked away in a ninth grade science book. After testing over 150 salts and hitting dead ends, they revisited the basics at a teacher's suggestion. 

There, they rediscovered ammonium chloride and barium hydroxide octahydrate, salts that absorb heat from their surroundings when mixed with water.

Using ammonium chloride, they could keep temperatures inside their prototype fridge between 35 and 43 degrees Fahrenheit, ideal for most vaccines. 

Barium hydroxide octahydrate brought temps even lower, suitable for organ transport. The result: a reusable, insulated container with a copper lining that works without electricity.

It wasn't a straight line to success. The teens initially relied on internet research that yielded disappointing results. 

When none of the tested salts produced the cooling effect they needed, they felt stuck.

However, that setback led to a breakthrough, and their personal connection to health care and the communities their families serve kept them motivated.

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They named the invention Thermavault and entered it in the 2025 Earth Prize competition. After winning the $12,500 award, they set plans in motion to build 200 units for testing across 120 hospitals in India. 

The impact of this project goes beyond innovation. It's about young people making a meaningful difference in their communities by developing low-cost, tech-based solutions rooted in empathy and education.

Now, the teens are working to secure certification from the World Health Organization so they can partner with global vaccine distributor Gavi. 

They're also pursuing a patent with guidance from an Earth Prize mentor, a step toward scaling their solution further.

By turning a classroom concept into a practical tool, these teens have made grassroots innovation feel personal, tangible, and effective. 

This kind of grassroots innovation mirrors a larger trend. From local climate action efforts happening across communities to initiatives that encourage people to donate to climate causes, more individuals are stepping up to build a safer, more sustainable future.

According to Pritesh Vyas, an orthopedic surgeon who piloted the prototype at V One Hospital, "It will be definitely helpful, definitely useful in the remote places, the villages."

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