Picture of Solar Thermal Cooker
Solar Thermal Cooker
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Step 1: Gather your tools and supplies

Picture of Gather your tools and supplies


  • (2) foam boards
  • 1 to 2 rolls reflective tape (alternative: 1 spray adhesive and 1 pack foil)
  • clear packaging tape/ duck tape
  • 1 box cutter
  • ruler (meter stick)
  • pencil
  • white string
  • sunglasses (to protect your beautiful eyes from the hot sun)

Note: It will take about 1 hour to build this solar thermal cooker (about 1' x 1' x 1'). This solar thermal cooker is good for toasting bread. if you leave the pan on the solar thermal cooker for about an hour, it would reach 150 degrees Fahrenheit.

Step 2: The Physics Involved

The solar thermal cooker will work best on a sunny day with low winds. We built this solar thermal cooker to make french toast. This is how the cooker works.

Solar radiation hits the reflective surface of the solar thermal cooker. The reflected light will concentrate in one area when angled to where the sun is. When you place a black pan [preferably a 9 inch or smaller one], the black surface of the pan will convert the reflected light into thermal energy. There is a medium amount of albedo but it doesn't alter the performance of the cooker [you want to toast the bread not bake/fry/burn it].When you put a piece of bread onto the black pan, the converted thermal energy will heat the bread, and then toast it.

Step 3: Preassembly: Preparing the foam boards

Picture of Preassembly: Preparing the foam boards

  1. Make sure that your foam board has smooth ends. if not, use a box cutter and trim off the excess ends.
  2. Lay a foam board on a smooth surface.
  3. The boards should be 25'' x 12'' [or 25'' x 10'' if you want a shorter board].
  4. Using the ruler, mark every 5 inches on the long sides of the board. Do this on both sides
  5. Use you markings and draw a line from the top of the board to the bottom. Your first line should be five inches from the end.

Nice job! How was the toast?