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Research and Comparison of Existing Concentrated Cookers

Parabolic Dishes

The team initially examined design options that rely on a reflective parabolic dish.  The geometry of a parabola takes incoming light that is parallel to its own line of symmetry and reflects the rays such that they converge on a single point in space called the focus.  This focusing of sunlight can result in very high temperatures in a dark object placed at the focus.  However, there were a number of issues with using a parabolic dish.  In a review of existing parabolic cookers, none of the designs reviewed could be used to fry foods, as they relied on enclosed pots and/or clear plastic bags as the cooking vessel.  This is related to the fact that the cooking vessel must intercept rays from many angles, unlike a flat cooking griddle that is heated from below by a wood fire.  Likewise, a parabolic dish is somewhat awkward to use, as energy is aimed at a point hovering in space, requiring the cook to reach across the dish to reach the cooking vessel, which can create performance problems when the cook's shadow falls on the dish and blocks the sun.  There are also safety concerns that users could easily burn themselves by accident if a hand strayed too close to the focus, the location of which is not visually obvious.

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