The goal of our project was to create a solar thermal cooker that is able to convert sunlight into thermal energy to cook the food of our choice. The maximum temperature we achieved was 138 degrees Fahrenheit. Someone that would be interested in this project maybe someone who can not afford to use an oven to cook their food and would like to use cheap resources to created a solar thermal cooker of their own. We chose hybrid box cooker design because it would be portable and easy to move around.
The total cost of materials will be about $10 or less. Some of these items can be easily found around the house. This project will about 2-3 hours to assemble. Also, if foam board is not available, you can replace it with cardboard.

Materials needed:
1 cardboard box
3 yards of foil
1 roll of tape
Foam board (14.5 inches x 14.5 inches and 17 inches x 17 inches)
1 yard of Saran Wrap
1 pair of Scissors
1 box cutter

Dimensions of the final project:
Width: 16 inches
Length: 16 inches
Height: 23.5 inches

The way that the light enters into our solar thermal cooker is that the sunlight reflects off the “walls” of the hybrid box cooker, which are all shiny and reflective cause they’re covered in aluminum foil, and goes towards the center of the cooker. The sunlight goes through the clear saran wrap and is focused onto the center of our black base. The light is focused towards the center because the largest “wall” on our cooker is bent down in a way that focuses the sunlight on the center.
Since our base is black, it absorbs the most light energy. This light energy goes into the box cooker, and with this extra energy, the molecules start to move around more. Since the molecules in the materials of the box cooker are moving around more, they begin to heat up. As a result, the light energy gets transferred into thermal energy. The heat energy is then transferred to the pan which heats up and cooks our hot dogs.

Step 1:

1. Cut three rectangular shapes out of cardboard. Each cardboard piece should be 16 inches x 8 inches.

Step 2:

2. Completely cover all three rectangles with aluminum foil and secure it with tape.

Step 3:

3. Cut out a square out of a Styrofoam board which will serve as the base. The base should be 14.5 inches x 14.5 inches.

Step 4:

4. Spray paint the square base black.

Step 5:

5. Cut out a larger rectangle that is 23.5 inches by 17.5 inches.

Step 6:

6. Cover this rectangular piece in aluminum foil and secure it with tape.

Step 7:

7. Tape all the pieces together onto the base and make sure they are secure. Cut another square base that is 17 inches by 17 inches and tape it to the bottom of the solar cooker.

Step 8:

8. Take the solar cooker outside and make sure it is facing the sun.

Step 9:

9. Cover the box cooker with saran wrap to prevent the heat from escaping the solar cooker.

Step 10:

10. Place what you are trying to cook inside a pot or pan, and put it in the center of the box on the square base.

Step 11:

Overall, our solar thermal cooker worked efficiently and we were happy with the results. Before our first trial, we just set the solar cooker outside and after just a few minutes, the base was already getting hot. However, the heat was escaping out of the bottom/base of our cooker. To fix this problem, we added another piece of Styrofoam board that was also black. This way, the box cooker would be more insulated and keep the heat from escaping from the bottom. The highest temperature that our solar cooker reached was about 138 degrees Fahrenheit.

During our second trial, we inserted the pan near the center and shifted the foil wings to concentrate the sunlight onto the center and onto the pan. After five to fifteen minutes, pan heated up and started to cook two hot dogs on the pan. We waited until the hot dogs turned a little bit darker, and that's how we knew that the solar cooker was working and actually cooking our hot dogs.

Some adjustments or changes to improve our hot dog cooker may be to get more stronger materials to cover our cooker with. The clear saran wrap was not durable or secure, so the heat still escaped the box cooker even though it was supposed to trap the heat inside. Also, it is important to make sure that the solar cooker is placed in a strategic location in which it would face the sun at all times. We recommend that all the surfaces are smooth and that there are not many bends and ridges on the surfaces because the more ridges there are, the less sun gets reflected.

Our group worked diligently to make this project possible, and our teacher Mr. Bording supplied us with the materials that we needed. If anyone use our steps to build a solar cooker, we hope it works for you, and good luck!