How to Build a Kyoto Solar Oven

The Kyoto solar oven uses sunlight to cook food.

The Kyoto solar oven design won its developer, Jon Bohmer, the Financial Times Climate Change Challenge (linked below). The simple design combines use of direct and reflected sunlight along with insulating methods to heat a chamber to cooking temperatures. This design is simple to repeat with common household and items easily available from the local hardware store. The resulting oven cooks in a method similar to crock pots or slow-cookers and is well suited to cooking rice, beans or stews.

Things You'll Need

• 1 Sturdy cardboard box (approximately 36 inches x 30 inches and 18 inches tall)
• Duct tape
• Heavy duty aluminum foil
• 1 Sturdy cardboard box sized to fit inside the first box
• High temperature flat black paint
• Straw, shredded paper or other loose insulating material
• 1 clear acrylic or Plexiglas panel to match the 36 inch x 30 inch box size
• Black metal pot with lid

Instructions

1. Open the top flaps of the larger cardboard box and attach aluminum foil (shiny side up) to the interior sides of the flaps using duct tape.

2. Remove the lid or top flaps from the smaller cardboard box and paint the interior of the box with high temperature flat black paint (such as a grill paint). Allow to dry thoroughly.

3. Place the smaller box inside the larger box and seat to give the most even spacing available around the inner box. Pack your insulation material between the boxes to help keep heat inside the inner box.

4. Lay the clear panel horizontally over the larger box opening; it should rest on the inner box and provide a loose seal.

5. Place wet food and/or water in the black metal pot. Lift the clear panel and place the pot inside the inner box. Lower the clear panel.

6. Set the Kyoto solar oven in direct sunlight. Position the reflective flaps to direct the maximum amount of reflected light into the oven. Use duct tape to fix the reflective flaps into the best configuration.

Tips & Warnings

• The interior of most solar ovens will reach or exceed 200 degrees F. As a result, food cooks in approximately twice the time it would take to cook in a conventional oven.

• Unlike oven or crock pot cooking, solar cooked food rarely needs stirring to avoid scorching the food.

References

• Ecofriend.org: $5 solar oven wins $75,000 green innovation award
• FT.com: Financial Times Climate Change Challenge

Resources

• Solarovens.org: Recipes for solar ovens