/diy/ - Do It Yourself

>>819658
You really have to be trying to make something that catches on fire and is a solar box oven. A solar funnel cooker (pic) or parabola solar cooker can set things on fire easily; like a magnifying glass.

As for your questions, it really depends on the design and style of the solar cooker. For overcast days the best one to use is a well insulated solar box cooker with lots of reflective panels. However, cooking temperatures do not need to be as high as a conventional oven. So long as it reaches 170F you are good to go. The length of time for cooking does increase. Thus, a high heat solar oven helps reduce cooking times.

On a fairly overcast day, my solar box oven can reach about 200F to 215F without too much trouble. It doubles that when the full sun comes out. In that cooker, I've cooked fried chicken and baked bread in the dead of winter with 2 feet of snow around me and -10F temps outside.

Obversely, you can use these things to chill stuff on a very clear night. Just point them at the open sky and they will lower the temps in the cooker up to 15 degrees sometimes. You can even make ice water. It uses the open sky as a heat sink and shields it from ambient heat in the surrounding environment.

>pic of my old funnel cooker at a worksite