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Simple Solar Cooker Answered


I was invited by GoWithFlo to add this project to the FullBellyProject group. From my understanding this group would be an ideal place to discuss improvements to the design and more importantly test it in the field.

Please don't hesitate to ask any questions and provide any comments!




I think what is needed is a large parabolic dome, say 4 ft wide in the centre of a village. People come with their cardboard boxes, place them on top in the middle and cut radial lines in them. Then you bend every second piece in. Next you bend the other pieces in. So it is like 2 layers of petals. Next you cut down round each top petal to remove a little off each bottom petal and you got a parabolic dish! Then you tape it together and you can have a deep focus parabolic solar cooker easily.

Thanks Lemonie. There are lots of different and effective solar reflective cooker designs available, what I am attempting to do with this design is simplify it to the point where the instructions to build it can be hand drawn on a few sheets of paper. This would allow anyone in any country to distribute, improve, evolve the design to fit their unique situations. The key thing is to have a design that does not require specialist tools, materials or written in any particular language. Hence the use of the rope/chain to get the shape of the reflector etc. Thanks for the link, there are some aspects of that design which could be considered. I especially like the way the alignment is done with the two tabs. Kevin.

I thought that drooping chains were catenary curves. Checking . . . yep. Still, they're probably close enough for governement work, but I read that tying the curves down at regular intervals (like a suspension bridge) will give you a parabolic curve.

Anyhoo . . .

Yes you are right and I have mentioned that in the instructions: "The cooker will use the curve of a hanging rope or chain which will be approximately parabolic. (google catenary if you do not know why) This shouldn't matter as a catenary gets closer and closer to being a parabola the wider you stretch it and we are focusing on a pot, not a point."

I've seen quite a few plans for solar cookers, and this seems to be as good as you can get with the materials you've chosen. The only real problem is the fact that it will only focus properly at near-equatorial latitudes, with the Sun high overhead. At other latitudes or times of day it would need propping up at one end to return the focus to the pot, or move the pot into the focus.

Yes, I agree, the drawings I have made do not show this clearly at all! I have mentioned this problem in step 8 of the instructable, it needs to have clearer details of how to use. The whole reflector can easily be tilted along its length, then rotated on the spot to face the sun.