In rural India, more than 400 million people live in areas where power grids are unreliable and few can count on electricity access around the clock. The inconvenience is tolerable for most, but can prove to be extremely detrimental for farmers, who need electricity to refrigerate perishable produce.
More than $10 billion worth of foodstuff is wasted in India annually as a result, much of it milk, of which India is the world’s largest producer. It’s estimated that 102 million gallons of milk is spoiled annually in India due to lack of refrigeration.
The solution to this problem comes from an unlikely source—thermal energy, a technique commonly associated with environmental efforts rather than the food industry.
Geo-thermal energy is harvested by channeling the heat naturally found under the earth’s surface for energy. Thermal coolants work in reverse, where coolant is channeled from a low-temperature material.
Recently, Prometheus Power sold its 100th thermal cooler to dairies in India. Instead of relying solely on electricity, Prometheus coolers store energy in phase-changing material (PCM), which absorbs heat when it melts, acting as a coolant during power outages.
During the heat-exchange process, the PCM is liquidized in a series of tubes that are submerged in heat-transfer fluid, which then absorbs heat from the milk via a stainless steel barrier.
“We call it a battery, because we treat it in the same way as an electrical battery: There’s a charging process and a discharge process to store energy for later use,” Sorin Grama, co-founder of Prometheus Power, said in a statement.
After winning second place at the MIT $100K Entrepreneurship Competition in 2007 for a solar energy generator made out of spare car parts, Grama considered developing a prototype for the India market, but decided to focus on making a cooler instead after discovering the magnitude of milk-spoilage in the country.
