Solar Powered Refrigerator

October 29, 2010 - 23-year-old Emily Cummins re-invented the refrigerator in her grandfather’s shed, when she was in high-school. The 43F (6°C) temperature that it maintains helps people in various African countries like Namibia, South Africa, Botswana and Zimbabwe keep their food for longer without using any electricity or atmosphere-harmful gas. Basically, the device is made from two concentric cylinders, with some space between them. The inner one is made of metal, to be thermally-conductive, and the outer one can be earth pots and plastics. Sand fills the space between them, which the users impregnate with water that evaporates when placed in the sun. For this invention Cummins has been named an Oslo Business for Peace Honoree. This solution was previously explored by Mohammed Bah Abba, who won a $100,000 prize at Rolex Awards 2008. Here's more by Ovidiu Sandru at GreenOptimistic.com.