Box Solar Thermal Energy Cooker

Introduction: Box Solar Thermal Energy Cooker

Hey! We created this awesome Box thermal cooker, follow the directions to replicate.

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Step 1: Materials

To make this EXACT model of a Solar Thermal Energy Box Cooker, you will need the following materials. Please remember that these are just recommendation, feel free to make you box as big or as small as you want.

  1. Regular Cardboard approximately 20 x 15 (1) 10 x 15 (2)
    1. You can look in recycling bins all over, and get this material for free
  2. Foam Board
    1. You can look here to find the correct pricing of the size of your foam baord
  3. Aluminum Foil approximately one roll
    1. At Walmart they sell them for $5.98 USD
  4. Glue Gun / Glue Stick
    1. You will need a glue gun, here is a mini glue- gun which comes with 10 glue sticks and it costs $5.99 USD
  5. Duct tape
    1. here you can find 1.88" x 10 yard duct- tape for $3. 37 USD
  6. Yard Stick
    1. An aluminum yard stick for $4. 97 USD
  7. Marking Utensil
    1. You will need anything that you can mark your measurements. We used a pencil so we could erase our mistakes easily; however you may use whatever you have handy.
  8. Something to cut with
    1. You will need something to cut your measurements with. We used a saw and a pair of scissors, but feel free to use whatever you have available or want to use.
  9. Glass 20 x 15 (1)
    1. We got our glass for free however you can get your glass here
  10. Spay Adhesive
    1. This will allow your foil to go on semlessly on the foam board and cardboard. Get yours here
  11. Plumbing pipes
    1. You can get this from a friend or any old steardy stick would do just fine!

*All links are the best prices that we know of/ and could find. Some are substitutes because the original was expensive.

Step 2: Logistics

1. What was the goal of your project? What were you trying to accomplish?

The goal of our project was to use the suns energy to bake the "mini" cupcakes you see above. We were trying to accomplish a green and efficient way to cook outdoors. We also hoped that people in places where the sun is prominent will use our box cooker design-- and save money and our Earth.

2. What was the maximum temperature achieved?

The maximum temperature that our box cooker received was around 150°F. Unfortunately since we used glass over our box cooker we could not get an accurate measurement of the temperature, but the water we put in our box bubbled a little, but it didn't quite boil, so the temperature was less than 212°F.

3. Who would be interested in building this project?

This project is for people who live in sunny areas, and have little to no access of ways to cook outdoors (or indoors) in a way that is healthy for their own well- being; as well as the environment. This project might also spark your interest if you are a person who loves building cool things, and respect the environment.

4. How long will it take?

This project should take no longer than 2 hours to make.

Step 3: Let's Get Building! (Before)

We first used our writing device to make one rectangle, 20 x 15, two 20 x 10 and two 15 x 10. We made these measurements on our foam board. The foam board is made out off hard materials so we had to use an electric saw to get the perfect shape, we so desired. We then used the duct tape to tape the pieces together and see if the fit. Luckily we did this because we ended up having to shave off a couple inches. After you have taped it, and made sure every thing fits-- take off all the tape carefully. Fast forward to the "make it shiny" step and then come back to this step. For the next step you will need your glue gun, with a glue stick inside, and place the pieces together and vuhla you're box is complete. The final touch would be to put your glass on top and make sure it fits.

Step 4: Cutting the Reflectors

After cutting the 4 foam board pieces, we assembled them roughly to make sure that all the pieces fit. We also put the glass on top to make sure that it fits perfectly. You want to make sure that the glass fits perfectly so heat will not escape! We then, cut the cardboard to make the reflectors of the box. You will need to cut (2) 15" by 10" and (2) 20" by 10".

Step 5: Making It Shiny

You want your foam and card board cutouts to be as "shiny" as possible. To be efficient, you should first line then up together equally. Then spray the edges first and continue to spray in a circular motion until you have sprayed all oh your boards. After you take your aluminum foil and simply roll it across the entire section. With your hand go back across the boards and smooth it out. Finally you break the pieces apart, and using your scissors cut any excess off.

Step 6: Putting It Together

The following will tell you how to put the reflectors on to the foundation of the box, that you created in the "Let's Get Building" section.

  1. duct tape the 20 x 10 reflectors to the side going the longest of the foundation box. Remember that you want the reflectors to be tilted so they can absorb more sunlight, and NOT cast shadows. You should want them at at about a 180 degree angle.
  2. On the side that is facing the sun, you want to create a large reflector. To create this, you take the two 15 x 20 card board reflectors and set them on top of each other. You then duct tape them at a 90 degree angle, but then bend it until it reaches a 75 degree angle or whatever degree the light is most intense at.
  3. If you put duct tape over your foil, simply spray adhesive over it and with foil paper cover it up!
  4. To ensure your reflectors do not move due to the wind, we recommend breaking your ruler in half and putting it behind your 20 x 10 reflector. For the largest reflector we recommend that you use the plumbing pipe or stick to hold it up.

Step 7: Last Minute Assembly & Tips

1. Find the Sun and then position your box cooker and reflective flaps so the sun reflects on your cupcakes. 
2. Make sure you have something to keep your reflectors in the place you need them to be. This is especially needed when it's a windy day. (Things that work are tape & toothpicks, sticks, or anything to rest the reflector on.  Duct tape is your best friend.)
3. After you put your cupcakes in the box cooker and secure the glass on the top, make sure there are no places where the air can get through. If there is, put some duct tape, more super glue, or whatever you think might help keep your box sealed. 

Helpful Tips:

The bigger the reflector is, the more light being reflected, which results in faster baking. We chose to build medium sized reflectors, but if you make the reflectors bigger, then more light will be reflected, which will make the inside hotter. 

Don't get discouraged. It might take a while to find the perfect spot, and to keep your reflectors up on a windy day, but in the end, you will have a nice dessert, dinner, or whatever you choose to make, and you won't be increasing your electricity bill.

Step 8: How Does This Work?

1. How does light enter the solar thermal cooker?

Light enters the thermal cooker through the reflectors, which we then are able to make it focus on a particular spot. The glass traps all the heat in.

2. Where does the light reflect? How does it become focused onto a single point?

Light is reflected on the glass which traps it to heat up the entire box, so the cupcakes can be made. It can be made to focus on one single point if maneuver the reflectors.

3. What parts of the solar cooker are designed to absorb the light? How do they absorb light energy and convert it into thermal energy, how does Albedo effect this?

The glass and the box are the parts of the solar cooker that are designed to absorb the light. How it works is that the the glass keeps all the heat and thermal energy in, while the box is "shiny" and reflects light-- while allowing the box to still keep heat in. This is effected by the Albedo effect because our pan is a dark color, so it would absorb more heat. We did not choose a white pan because light will just be reflected and white does not absorb heat.


The box cooker creates a green house effect because the glass traps the sun's heat or warmth inside which makes the cupcakes or whatever food you desire to be cooked. Also, the foil inside the box will reflect light onto the cupcake pan.

Step 9: Final Look! (After)

Finaly you're able to pop in your mini cupcakes or whatever food you desire. The mini cupcakes took about 1 hour to be cooked completely. We did put hot water in ever other empty space just to make it heat a little bit faster. Does yours look like this?!?

Step 10: How We Feel

1. How well did it work? What did you cook?

We felt that that this boxer was so cool. It was successful because it was hot enough to make all the mini cupcakes. The only con is that you will have to check on it every 8-9 minutes to make sure that the reflectors are at the right angle because the earth moves-- which cause the sun to change its position.

2. How hot did it get?

Our box cooker got up to about 150°F

3. Are you happy with the final product? What would you change for next time?

We are very happy with the final product because we were able to make mini cupcakes using only the SUN! How awesome is that?!? And they tasted ah-mazing for the record. The only thing we would change for next time would be to try and come up with a way that makes the wind not move the reflectors too much.

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