Images credit Solare Bruecke
One of the inconveniences of solar cooking is that it is, well, inconvenient to have to go outside when you would rather be in your kitchen, doing other things while the pot is cooking. Kris de Decker of No-Tech magazine shows a very clever design from Solare Brücke, which was founded in 1992 " to contribute to balancing global inequalities and to promote the dissemintation of renrewable energies." They have come up with a very clever design that tracks the sun and accurately aims it through the kitchen window right onto the bottom of the pot.
To make cooking simple and comfortable the cooking-place should not have to be moved, even better: it should be inside the house and the concentrating reflector outside in the sun. The best solution was a eccentric, flexible parabolic reflector which rotates around an axis parallel to earth-axis, synchronous with the sun. Additionally the reflector is adjusted to the seasons by flexing it in a simple way.
The reflector is a small section of a larger parabola, chosen so that "The sunlight that falls onto this section of the paraboloid is reflected sideways to the focus located at some distance of the reflector." It rotates exactly on the north/south axis because it is mounted on a frame that is set on the angle perpendicular to the sun at the equinox. Since there is some seasonal variation, they can actually flex and distort the reflector.
Here you can see the sun hitting a reflector under the pot, bouncing up to the black bottom of the pot. That's not a huge target; one has to adjust the flex of the reflector every two or three days. In Europe, they use more sophisticated photovoltaic tracking devices.
The system has been used for steam heating, and has been focused on iron blocks for heat storage. One can think of so many uses, from solar powered air conditioning to water heating. What a neat idea. More at Solare Brücke.
More Solar Cooking:
TreeHugger Picks: Solar Cooking
Fancy Solar Cooker Concept a Possible Solution For Off-Grid Communities
Solar Cooking Extreme - Eggs in Ten Seconds