People may initially wonder about the utility of a solar cooker when they first consider them, but most solar cooker and solar oven owners never look back. They enjoy the fact that they cut out all fuel costs, and every time they use it they are actively recouping their investment in purchasing or building the solar oven. They also enjoy being a part of a sustainable future for cooking, as they test and find more and more recipes that are delicious even when making the food requires no greenhouse gas emission.
That being said, different kinds of solar cookers advantage different aspects. For instance, some cookers can bake bread or muffins admirably, but others will never provide the kind of heat necessary to create baked goods, only great fried/boiled dishes. Others work only in the perfect kind of light, while others can catch enough sunlight in any position to cook admirably.
Box Solar Ovens are an interesting example; some basic models involve a single reflector into a box with reflective material in its lining that concentrates the sun onto a single pot. This basic model can be incredibly inexpensive and can even be made yourself. Box Solar Ovens have also been expanded to include 4 foldable reflectors. They are great in that they can be quite inexpensively made at home and they have the ability to bake. That being said, they are less portable than other cookers, aren’t great for frying, and tend to need high angle sunlight to work, since low angle sunlight (such as sunrise and sunset light) won’t enter the box easily.
Panel Solar Cookers are similar in design because they still involve focusing reflection panels onto a pot, but instead of using a box with a reflector lid or flaps, they are constructed through a foldable, angled panel with a pot set in the middle. These ovens are amazing in that they are portable and inexpensive, allowing people all over the world to cook with no fuel needed. These are not always long-term solutions, since some of the materials used to make the less expensive panels break down over time, and they are ideal for warming and boiling food but not for baking or frying, given their low maximum temperature that tends to be around 248`F. A version with vinyl-covered panels is notable for its curved-panel design, and other simpler designs have great success as inexpensive options produced all over the world.
So the context for a Box Solar Oven versus a Panel Solar Cooker is usually different: Boxes, being more durable and less portable, are great for putting in one place and using frequently in that same area. Panels, on the other hand, are good for moving around and for short-term needs, which is part of why many of them have been used in refugee camps around the world!
Box and Panel are only two of the options available for fuel-free solar cooking. To see all major solar cooking technology compared side-by-side, check out this blog post.