Here is an idea for a solar cooker that is easy to build and is versatile. Solar cookers do not have to be complicated or require expensive hard-to-work with materials. In fact, the simpler (and cheaper!), the better as far as I’m concerned. The first ones I built were a variation of the funnel types made with two rectangular reflectors fastened together at one end and spread out at a 45 degree angle to form a wedge. Each reflector was about 18 inches by 30 inches. An isosceles triangle, 24 to 30 inches tall was used as the bottom reflector. The beauty of this type, besides being super simple to build with no complicated angles or folds, is that it is very efficient and works well whether the sun is low (winter) or high (summer) in the sky. Another positive attribute is that it only has to be adjusted on the horizontal axis, not the vertical like some more complex styles of funnels. It is also a good style for camping, traveling, etc. because it all folds up flat. The downsides are that the ends need to be staked down if it’s windy and it requires the use of an oven bag to insulate the cooking vessel from the ambient air.
I have wanted to build a solar cooker that was not susceptible to wind and didn’t require an oven bag for insulation. I have made a couple of box cookers/ovens, but could never get them to work very well. It seemed I just couldn’t get them to heat up enough to cook. However, the other day I was out in my shop and saw an old wood ammo box and thought I would give the box cooker another try.
· A large wooden box with lid
· Heavy duty foil
· Spray adhesive
· Heavy cardboard
· Some ¾ inch pine boards
· A 5/16 inch wood dowel rod
· A piece of plexiglass or glass to fit the box
This box was made from ¾ inch pine and is about 16 inches by 20 inches and 9 inches deep and has a hinged lid. You can look around army surplus stores or yard sales or just build your own wood box. You could use a cardboard box, but it would need to be insulated and would be susceptible to wind. The first thing to do is to line the box and lid with foil using the spray adhesive. This is not an oven and we don’t want to waste solar energy heating the box, so the entire interior is reflective, not black as some cooker/ovens are constructed.