Recommended for High School and K-8.
Solar cookers convert sunlight into heat energy. They are a low-cost, pollution-free method of food preparation. Under normal conditions, solar cookers can reach temperatures between 80-120°C (175-250°F). Since food cooks at around 80-90°C (175-195°F), solar cookers are hot enough to fully cook food, but not to burn it or dry it out.
There are three common types of solar cookers: box, panel, and curved concentrator. Box cookers have transparent tops for sunlight penetration, dark bottoms for heat absorption, and reflective sides to reflect the heat back toward the cooking pot. They can accommodate multiple pots and typically reach moderately high temperatures. Panel cookers are built from reflective panels arranged in such a way as to direct sunlight onto a dark cooking pot. They are the simplest and cheapest to make, but their temperature range is the lowest of the three designs. A curved concentrator is built from a 360° parabolic reflector with the food placed at the focal point of the parabola. Curved concentrators can achieve very high temperatures, but they are difficult to construct, require frequent repositioning, and can cause serious eye damage from misdirected reflections. No matter which design is chosen, the effectiveness of a solar cooker is dependent upon the transmissivity of the cooker, the heat absorption and retention properties, and the amount of concentrated sunlight.
- Build a container for cooking with energy from the sun.
- Determine the optimum sun angle for your location, day, and season.
- Create an 8-hour temperature profile for a solar cooker.