Examples of Results in 2009
@In the Winter Sciece Camp 2008, we made three concentrator type, five box type and two panel type solar cookers. I would like to introduce you some interesting results and facts clarified through the analyses. These knowledge are new to me and I enjoyed them a lot. Do not try to mimic the successful ones but try a new improvement. I'm not expecting an old success but new findings by you!
Both above two solar cookers are enlarged Educooker004's having different diameters.
As for the concentration, they have the same performances. This means that the larger one can utilize larger amount of energy. This year, the cooker which outperformed most was the larger concentrator type.
I do not have the numerical analyses for those two box type solar cooker, but I would like to comment on those two. One of them has a inner box with very small aperture and deep depth. They tried to reduce the volume of the inner box but in this case the light cannot hit the bottom of the inner box at all. The booster mirror of the second box type was adjusted incorrectly and as a result, the inner box was not able to intake enough light. Unfortunately both two failed to cook foos.
Those two box type solar cookers have two booster mirrors.@One of them have a shallow inner box. Both of them succeeded to cook foods, but the analyses clarified the difference of their perfomances.
According to the analyses, the second box type cooker with curved booster mirrors has a area where the light strontly concentrates. If you put the pot there the cooker can have a very high concentation rate as a box type solar cooker. However of course, the curved booster mirrors have a problem in compactness when folded.
Generally speaking, the concentration rate of the panel type solar cooker is between that of concentrator type and the box type. Also, the heat insulation capacity of the panel type is between concentrator type and box type. I think it is a kind of concentrator type because you need to aim the pot with a group of mirrors. Just for a criterion for comparison, our Educooker003 has a concentration of 47%.
As for the first one, they tried to make a 2 dimensional parabola but the shape is not exact. A group of reflectors on the top does not contribute to the increase of light on the pot. As for the second one, they should have determined the dimensions and shapes of each panel carefully. Especially the mirror at the back is too large and the two side mirrors are miss directioned. Just imagine that you are holding a hand mirror at the position of each panels.
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