I've used a couple different kinds of
solar cookers at our school in Ladakh, which is high desert, so it's ideal for
solar power.
The reflector box cookers are great for the gee-whiz factor, but we never used them regularly. They can bake a small volume of items, and do better with sweet things than not, because I guess the sugar browns nicer. Baking is not a tradition here, and the box ovens we have had were too small to really produce much. I have met people who claim to cook other things in a box cooker, such as rice, but when we tried it, it fogged up the glass and the whole thing cooled down. We have two sitting around impressing people but not being used.
Parabolic reflector cookers that concentrate the sun's rays with a roughly parabolic disk of shiny material have been much more effective for us. The small ones, about 4 feet diameter, work pretty well, but you have to go outside and turn them every 15 minutes or so. They are too small for the numbers of people at our school, but they would be great for cooking for 2 or 3 people, I think. These are more like stovetop cooking and you can cook all kinds of pots of food on them. I've seen two models, one with the dish low to the ground and the pot raised, and one with the dish and the pot at about waist height. They are pretty affordable to put together from shiny aluminum or steel if you can make the frame. In your first week of having one, it is a rite of passage to burn holes in some clothing that you think will dry quickly by draping it on the solar cooker.
At our school we use a big Scheffler reflector type cooker, with a parabolic dish about 8 or 10 feet in diameter, focused on a hole in the (non-flammable) wall and a secondary reflector shining up to the pot. This works very well, and we can cook big pots for 50 people on it. Ours have gone through two models of self-regulating mechanisms, where you'd weight the thing down with a stone, pull it over towards the east in the morning so the stone goes up, and a tick-tock pendulum mechanism would control its speed turning back to the west as the stone pulled down. Both mechanisms failed, and now we just turn it by hand every 15 minutes or so. Either way, you have to make a seasonal adjustment every few weeks. It's a bigger investment, and rather complex engineering to get the angles right, I think. I don't even know where the designs are; I hope they are
online as Scheffler cooker. Ours was installed by a Swiss guy in the 1990s who came around and trained lots of
local people in how to fabricate and install these, and we've been using both ever since. The others that were installed in our region are no longer used. User motivation is essential.
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![[Thumbnail for scheffler-solar-cooker-at-secmol-in-ladakh.jpg]](/t/64491/a/49200/scheffler-solar-cooker-at-secmol-in-ladakh.jpg "Filename: scheffler-solar-cooker-at-secmol-in-ladakh.jpg
Description: Scheffler parabolic solar cooker at SECMOL in Ladakh")
![[Thumbnail for pressure-cooker-on-solar-cooker-at-secmol.JPG]](/t/64491/a/49201/pressure-cooker-on-solar-cooker-at-secmol.JPG "Filename: pressure-cooker-on-solar-cooker-at-secmol.JPG
Description: Pressure cooker on a solar cooker at SECMOL")
![[Thumbnail for scheffler-solar-cooker-diagram.gif]](/t/64491/a/49202/scheffler-solar-cooker-diagram.gif "Filename: scheffler-solar-cooker-diagram.gif
Description: My rough diagram of how the Scheffler cooker works")
