Rolex Award description of an effective earthenware method of keeping food and medicine cool in the Nigerian (and any other) desert. It is called a zeer in Arabic.
The impact of the pot-in-pot on individuals’ lives is overwhelming. “Farmers are now able to sell on demand rather than ‘rush sell’ because of spoilage,” says Abba, “and income levels have noticeably risen. Married women also have an important stake in the process, as they can sell food from their homes and overcome their age-old dependency on their husbands as the sole providers.” In turn and, perhaps most significantly for the advancement of the female population, Abba’s invention liberates girls from having to hawk food each day. Instead, they are now free to attend school and the number of girls enrolling in village primary schools is rising.
A promising high tech non-electric refrigeration system comes from Denmark, a magnetic cooler described as a physics breakthrough that I found searching Digg. An in-depth description is found at Wikipedia’s Magnetic Refrigeration page.