Can combined troughs replace parabolic dishes for amateur solar cooking? Answered
I have being doing limited testing of the combined trough shown below and it seems to work as expected. I used a 4ft by 8 ft piece of corrugated plastic for the big trough (too wide but I was reluctant to cut it). Compared to dishes, this was incredibly easy to make and actually gives more reliable concentration over a longer time period.
Would anyone like to try it on tiny demo scale? (I mean something tiny made with 1ft by 2 ft paper perhaps) see if you can make a panel cooker with the design as a template?
I think it will work with hemisphere curve, or parabolic curve, any curve or panel cooker shape that shines the light on a cooking vessel.
Key points. 1 The troughs must be curved in directions that are at right angles to each other.
2 the long primary collector trough must be in line with the path of the sun.
And thats basically it! The primary trough concentrates light in one plane and the secondary trough (the little wings round the red pot) concentrate it in the other plane.
I then tried to get software to show if it was any good and It seems to show that it would cook for significantly longer than a parabolic dish. But the software showed that it was not as good as I had hoped. From running the software (art of illusion) I came up with the kyoto trough as a possible solution.
The kyoto trough is a trough made by taking 2 halves of a parabolic trough and twisting them a little inwards roung the focus. This can focus all the light between the focal line and the bottom of the trough for a time period coresponding to the angle of twist. 15 degrees of twist coresponds to one hour. http://www.youtube.com/watch?v=uX9Z-nsUHiA. That is a really useful property because it confers reliability. The next part of the kyoto trough can just be an ordinary parabolic trough to do a final concentrationof the light onto the cooking pot. Well 2 small troughs to deal with 2 streams of light going towards the cooking pot from either side of the trough.
Are any mathematicians interested in resolving the troughs into a Kyoto Dish? which would give much longer cook times than a parabolic dish.