How can someone construct a solar powered oven locally? This really good question came from a reader of this blog in response to the post Solar Powered Cooking Oven. There are several good resources on building your own solar oven, and I’m going to summarize them here.
Start with a Black Box
Any kind of non-toxic, non-shiny waterproof box will work. A box with suitcase-size dimensions will allow you to use a medium-sized baking pan that is about 9 by 12 inches.
Next you will need to paint it black with a food-grade, heat-resistant paint. In a poor country, I’m not sure where you can readily find this kind of paint, but most hardware stores in developed countries sell oven paint. Paint the inside of the box thoroughly, air dry and give it a second coat. Air dry until the pain is cured and all of the gases are clear.
Add a Glass Lid
The glass lid does a few things: keeps the heat in, traps moisture and keeps critters out. Attach the glass to the box with a hinge on one side so that you can easily lift the lid. On the opposite side, attach rubber feet so that the glass will seal when closed. Finally add one or two small screw hinges or clamps that firmly hold the lid closed.
The reflectors gather the sunlight and focus it into your black box. You can use any sturdy outdoor material (i.e., plastic, wood, metal) as long as it’s waterproof. Cut four pieces, one the length of each side of the box and attach them to the top of the box. Cover them with a shiny, reflecting material. Aluminum foil or paint will work. Just make sure than reflecting surface is smooth and shiny.
A few optional items will make the oven easier to use: a thermometer inside the oven, carrying handle, a swivel tray inside the box and an adjustable leg to raise and lower the oven to match the angle of the sun. If you can’t find these, the oven will work without them.
However, you need a non-reflective pan for cooking. It can be glass, cast iron or even teflon just as long as it’s not shiny. A shiny pan will reflect the heat away from your food, which defeats the purpose.
Another reader in India mentioned that she uses a parabolic cooking dish like the one shown above to capture sunlight and slow-cook food. You cannot fry or bake on high heat, but the design is much simpler. It is literally a curved dish with the depression in the center. So if you can’t find the materials locally to make your own solar oven, try a parabolic cooking dish. You might even try recycling an old satellite dish, cover it with reflective material and voila!
Good luck and let me know how yours turns out!