Cook food using the sun’s heat: Build a solar oven

From a yard in Kampala, Uganda, Moses explains how to build a solar oven using a tire, some glass, newspaper, silver foil, tape, a black pot, and a few hours.

If you’re cooking outside or don’t have an oven, solar ovens are a great alternative for making a hot meal. Building materials are generally inexpensive and easy to find, and rather than requiring fuel or firewood, solar ovens take advantage of a sustainable resource: the sun. How does it work?

• Concentrating sunlight: A reflective mirror of polished glass, metal or metallised film concentrates light and heat from the sun on a small cooking area, making the energy more concentrated and increasing its heating power.

• Converting light to heat: A black or low reflectivity surface on a food container or the inside of a solar cooker improves the effectiveness of turning light into heat. Light absorption converts the sun’s visible light into heat, substantially improving the effectiveness of the cooker.

• Trapping heat: It is important to reduce convection by isolating the air inside the cooker from the air outside the cooker. A plastic bag or tightly sealed glass cover traps the hot air inside. This makes it possible to reach temperatures on cold and windy days similar to those possible on hot days.

• Greenhouse effect: Glass transmits visible light but blocks infrared thermal radiation from escaping. This amplifies the heat trapping effect.

For more information about how to make different kinds of solar ovens, visit MAKE, Instructables, Dummies.com, or come up with your own solution! Then try these: 6 Beginner Recipes for Solar Ovens and Solar Oven Smores.

There are more inventions and sustainable ideas in the archives, including Spain’s first 24/7 Concentrated Solar Thermal Power plant.

Updated video.