Sun Oven - works well. I've cooked a 3 lb roast in about 1 1/2 hours. Not cheap but effective. You do have to turn it to realign it about every 30 minutes or so. Products - Sun Oven® | The Original Solar Oven & Solar Cooker I did a little writeup on it a couple of years ago...
I've been happy with my Sun Oven. The only complaint I've had is that it won't hold larger pans/pots.
Ed, you will have problems with one in your hidey hole. You need to rotate them for the sun, tracking it around, well, you need a window to match. Of course, if you can bring yourself to it, the roof should be a good place to try it out.
Haven't tried it, but I believe with an extra pot purchased from them, you can double-stack. The top pot's base fits into the lower pot's recess normally used for the lid. Then you can put the lid on the top pot.
I have a big black cardboard box with 4" thick walls and bottom and a glass top with a big reflector that's about 3/4 complete, Every time I think about doing anything with it I realize it's winter, and the sun is less than optimal. And so it sits on the shelf, where its been for ten years or so, waiting for me to get it done. My experiments with smaller scale solar ovens (slow days at work) in the summer were promising, but in the winter the same experiments became frustrating. It required dedication and patience to get everything right. Your power source is always moving out of perfect alignment, and is affected by weather and season. Somewhere about Plan D on my list of cooking options.
Built a 2x2x18 configuration from some old ply from a job site. Used polished aluminum for the reflection parts; those pieces came from a trailer building site. It was heavy and durable. The second generation unit used 3/8 ply for the base and 1/4" luan board for the reflection units. Glued polished aluminum to luan board. Much easier to move. The next version will be in the shape of an pentagon or octagon. Just to see if it improves the heat levels.
This real issue is timing. You have to cook one time a day at mid day for all 3 meals. There was a post somewhere from a woman who showed how to organize your meals so you cooked one time a day on a sun oven and then just heated with small stove or fire in the evening and morning
