# New "compound" parabolic solar cooker to try.



## gaiatechnician (Sep 24, 2008)

A parabolic dish focuses light to a sharp point (which is great unless you put your eye or hand there or burn a hole in your pot there).
Another big problem with the parabolic dishes is that that spot of light only happens if the dish is pointed EXACTLY at the sun. So as the sun moves across the sky you either have to move your dish constantly or your point of light quickly spreads out away from the food.
The compound parabolic dish does not produce a point of light. It produces an area of light. If the sun is within the "acceptance angle" (if it is pointed relatively accurately at the sun) the light lands on an area that extends from the focus to the back of the dish. In the dish I made the acceptance angle to be 45 degrees which means that it accepts the light from the sun and puts it on the pot for up to 3 hours without moving the pot! Compared to a parabolic dish, this is awesome performance! Please check it out. 
I have details at instructables.com and at utube.com and my username in both places is gaiatechnician. 
I designed mine for a specific cooking pot. The pot can bring 7 l (about 14 pints) of water to over 90C. This is hot enough for pasturisation or slow cooking of stews,etc. I include a template on instructables if you want to try to make one yourself. 
http://www.instructables.com/id/Make_a_quotcompoundquot_parabolic_solar_cooker/
Brian White Victoria, BC Canada


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