There are two types of solar ovens. The most common is the "direct heat" solar oven that uses reflectors to direct the heat into an "insulated" box. The will work in warm climates as long as you keep them turned and tilted in the right direction and angle. They are big, bulky to store and are better at warming leftovers (if you have a few hours) than they are for cooking.
The "indirect heat" type of solar oven is an improvement in that it is better insulated and you can use charcoal or a fire to heat it if the sun is not available. It has an exposed metal top (an inverted heat sink) with the other five sides well insulated. You direct the light from the sun through a Fresnel lens onto the center of the top. Depending on the size of the lens and the distance from the focal plane you can get some very high temps (which are controlled by varying the distance to the focal plane). Just like any other solar device you have to keep the lens between the top plate and the sun. It is very labor intensive and as a general rule not very good except in bright sunlight on warm days. O cloudy days you can place a charcoal ring (just a steel ring) on top and build a fire or burn charcoal to warm the oven. It still takes a long time and you have to tend the fire (it is rather small) to keep a proper temperature.
A dutch over in a fire pit is much better as far as an investment goes.
The "indirect heat" type of solar oven is an improvement in that it is better insulated and you can use charcoal or a fire to heat it if the sun is not available. It has an exposed metal top (an inverted heat sink) with the other five sides well insulated. You direct the light from the sun through a Fresnel lens onto the center of the top. Depending on the size of the lens and the distance from the focal plane you can get some very high temps (which are controlled by varying the distance to the focal plane). Just like any other solar device you have to keep the lens between the top plate and the sun. It is very labor intensive and as a general rule not very good except in bright sunlight on warm days. O cloudy days you can place a charcoal ring (just a steel ring) on top and build a fire or burn charcoal to warm the oven. It still takes a long time and you have to tend the fire (it is rather small) to keep a proper temperature.
A dutch over in a fire pit is much better as far as an investment goes.
