How Solar Ovens Work
- Solar cookers all work by using the sun's rays to cook food or boil water. They are cheap to build and cost nothing to run, which makes them excellent for developing countries and people living far off the grid. The fact that they require no fuel also makes them popular with environmentalists seeking to conserve energy.
- The simplest kind of solar cooker is the panel cooker. A panel cooker uses flat panels covered with a reflective coating to direct solar energy. The panels can be made of cheap materials such as cardboard, and simple aluminum foil can be used to for the coating. The panels direct solar energy towards a black pot above the solar cooker. Because the pot is black, it absorbs most of the light, turning it into heat. The bag is wrapped in a plastic bag, which stops the heat from flowing out into the air. Panel cookers can not usually reach very high temperatures, but they are hot enough to cook grains and, on sunny days, can be used to cook vegetables and meats as well.
- Curved concentrators work like high-tech versions of panel cookers. Instead of flat panels, a parabolic or bowl-shaped reflector focuses the sun's light on a pot. Depending on the size of the reflector and the weather, these solar ovens can produce as much heat as conventional ovens. The one drawback is that they need to be tended, since the movement of the sun can throw them out of focus.
- A box oven is an insulated box with a plastic or glass top to trap heat inside. The sides and bottom are either black or reflective, and a black pot is placed inside. Box ovens with reflective sides reflect sunlight onto the pot, which converts that light into heat. In black ovens, the sunlight turns into heat as soon as it enters the oven, and that heat is then radiated towards the pot. This type of oven can reach temperatures of 300 degrees Fahrenheit, hot enough to cook food but a little cooler than most recipes call for. Because of the low temperature, food can take a bit longer to cook in box ovens.
