Milk storage unit uses sun to keep cool

Got chilled milk?______

That’s the unofficial slogan for Boston-based Promethean Power Systems, a company that this month received a grant from the National Science Foundation to further develop its innovative milk refrigeration system.

Promethean’s target market is India, though it plans to expand to Africa and Latin America as soon as February. India is the world’s largest producer and consumer of milk; the country is home to some 70 million farmers who contribute to a multibillion-dollar dairy market.

Because temperatures can reach 100 degrees during peak summer months, raw milk begins to spoil within hours of collection. And India’s frequent blackouts, due to a strained power grid, make it difficult to keep milk cold enough.