Solar-powered fridge off the grid
New design helps India’s villages cool food via a solar-powered refrigerator.
A startup based in Cambridge, Mass., has developed a new solar-powered refrigeration system for food storage in Indian villages that are off the grid. Promethean Power Systems' design is a hybrid of conventional compressor-based refrigeration and thermoelectric materials--semiconductors that convert electricity into cooling and vice versa.
The chilling units will be cheaper than what is currently used in Indian villages, most of which are off the grid. In such villages, food distributors and processors store raw food products in traditional compressor-based cooling units that run on diesel generators. These cost about $12,000, says the company's cofounder Sorin Grama. And that cost, says Grama, doesn't include the escalating cost of diesel needed to run the units. During a month spent in India a year ago, Grama and his cofounder, Sam White, identified a crucial niche.
Grama says that even including the expense of the photovoltaic (PV) panels, his design would cost about the same as or slightly less than the diesel-powered refrigeration units. More important, it would have no fuel costs, and almost no maintenance costs. According to the company's initial calculations, using a compressor combined with thermoelectric modules would use 20% less power to generate the same cooling as a compressor alone.