Solar cooling outfit shows prototype, lands funding

CAMBRIDGE, Mass.--Promethean Power Systems, a start-up developing solar-powered refrigerators for India, has raised a round of angel funding from the Quercus Trust.

The funding, finalized Thursday, will allow the company to build another prototype which it hopes to test in India next year, according to company CEO Sorin Gramma.

Promethean Power showed off its first prototype this week at the Technology Review EmTech 2008 conference.

The Massachusetts Institute of Technology spinoff is combining solar power with thermoelectrics--materials that create cooling or heat from electrical current--to make a standalone refrigeration unit for rural India.

At the heart of its system is what it calls its hybrid compressor, a cooling unit that can run both off of a diesel generator and three to five 180-watt solar panels.

Solar panels make this sort of refrigerator far more expensive. But Gramma estimates that a milk or food distribution company could save two-thirds what it spends picking up food from farmers.

The refrigeration allows for one, rather than two, milk pick-ups a day. Also, by squeezing as much power as possible from the sun, these cooling stations don't need to run their generators as often.

The electricity from the panels flows through the thermoelectric modules. A heat-exchange system of water tubes creates ice for cold storage, while the heat is whisked away.

Gramma said the company is probably two years away from having a commercial product.

The Quercus Trust, run by David Gelbaum, keeps a low profile but has made a number of seed investments in the clean-tech area.

"The Quercus Trust is a leading investor in solar and other clean-tech technologies and is proud to provide Promethean with capital to further its goal of providing better living conditions for the communities that can most benefit from this technology," it said in a statement.