A woman milks a cow in an Indian village.

A woman milks a cow in an Indian village.

Lance Casey

MIT grad brings new refrigeration system to rural India

Every year in India, millions of gallons of milk gathered by rural farmers from their small herds spoil on their way to market. Last week, the co-founder of a U.S. startup company that is trying to solve that supply chain problem was named one of seven “invention ambassadors” in a new program that highlights the value of technology-driven solutions to global problems.

When Sorin Grama graduated with a master’s degree in engineering and management from the Massachusetts Institute of Technology in 2007 and started Promethean Power Systems with entrepreneur Sam White, their goal was to sell solar power concentrators to generate electricity in clinics and schools in villages without a dependable source of electricity. But the villages couldn’t find a use for the expensive technology, so Grama and White turned their attention to the country’s dairy industry, which is dominated by farmers with a few cows and who depend on rickshas, bikes, or their own feet to transport the warm milk on the first leg of its long journey from farm to local village collection center to the dairy plant. “[Milk] really is like liquid cash to them, because milk is something you harvest and sell daily,” says Grama, an electrical engineer who invented a refrigeration system to help these villagers keep their milk fresh longer.

On 1 July, the Lemelson Foundation announced that Grama and six other inventor-entrepreneurs had been named invention ambassadors. The event, co-sponsored by AAAS (which publishes ScienceInsider), marks the start of a 3-year effort to engage inventors with the public through talks with everyone from high school students to policymakers.

Grama’s invention is called the rapid milk chiller, a dome-shaped machine that couples to a thermal energy battery to cool milk from 35°C to 4°C. The rapid milk chiller cools the milk by means of a heat exchange with cold fluid inside the dome. When electrical power is not available, the rapid milk chiller can cool up to 500 liters of milk using only the thermal energy stored in the battery.

Dairy plants install the chiller-battery pairs in village collection centers. Now, villagers can keep their milk fresh for up to 2 days. Dairy trucks don’t have to make daily rounds and no longer have to transport milk from a village collection center to a separate chilling center. The dairy plants can also extend their reach to more isolated villages with rapid milk chillers.

Promethean Power has sold 60 chiller-battery pairs to dairy processing facilities since the first one was installed 3 years ago. The company plans to produce more chiller-battery pairs as demand rises, and Grama and White hope to apply their technology to cool vegetables and other perishable food items.