Solar ovens aren’t a new phenomenon, but with the worldwide interest in alternative energy growing, new attention is being focused on them.
NGOs are distributing them to impoverished villages where deforestation and desertification are a problem, and they’re also popular in places where fire risk is extremely high (for instance, with campers inside particularly dry national parks).
One interesting fact about solar cookers is that many of them use the greenhouse effect to cook food: solar rays are reflected and concentrated inside a glass box, which traps increasingly hot air inside. As the temperature builds, your food cooks, and even the humblest of solar ovens can reach 350 degrees in about 30 minutes.
The main problem with these contraptions is that they function best during the hottest parts of the day — when people are the least likely to want a hot meal. But a Colorado company has found an ingenious way to use the midday cooking power of the sun to their advantage: by roasting coffee....
From Mental Floss
Here's a 1959 model at Bizarre Labs
Here's the list of partners working with Solar Household Energy, Inc.
Solar Cookers International's list of projects
The Cornell Solar Cooking Team: Design for Solar Ovens For Use in the Developing World 14 page PDF