Comparing Solar Cookers
When comparing solar cookers, you should consider how you want to cook with your cooker; different types of cookers might be great at one kind of cooking (baking, frying, slow cooking, etc.) while they are ineffective in others. You may need to use multiple types of cookers to reach your goals. Before searching your choices think about the following questions:
- Where will you use your solar oven (camping, at home, for emergency evacuation?)
- Are you prepared to modify cooking habits to adjust to a new technology?
- How often do you plan on using the solar cooker daily or just on occasion?
- Is there constant sunshine where you plan to cook?
Solar cooker types
Box cookers typically cook food at temperatures between 110°C(230°F) and 175°C(350°F). They can often accommodate multiple pots, and usually take between one and three hours to cook various foods. The sides and bottom are insulated to retain cooking heat. Worldwide, they are the most widespread. There are several hundred thousand in India alone. READ MORE
Panel cookers incorporate elements of box and parabolic cookers. They often have a large reflector area and the cook pot has some form of enclosure to retain heat. Panel cookers are capable of cooking at approximately 150°C(300°F). They are the easiest style to make and relatively inexpensive to buy. READ MORE
Parabolic solar cookers use a bowl shaped reflector to focus the light directly onto the cook pot, usually from below, and typically do not require a greenhouse enclosure to retain the heat. The parabolic name refers to the shape of the curve of the reflector cross-section.
There are two main types of parabolic cookers; shallow parabolas and deep parabolas. Shallow parabolas require more frequent reorientation to the sun, possibly every fifteen minutes, but they cook food more quickly at higher temperatures compared to other solar cookers, often reaching temperatures over 315°C(600°F). They also have the ability to fry and broil foods. Many, but not all, shallow parabolas can present a fire hazard because the focal point is outside of the body of the parabola.
Deep parabolas reach lower temperatures than shallow parabolas,175 C(350°F), but can go as long as four hours without being reoriented. READ MORE
Evacuated tube literally means that the cooking chamber is constructed of two layers of blown glass in the shape of a sealed tube, where the air has been removed between the layers. Heat loss happens primarily by conduction and convection through a medium. With no air between the layers of glass the chamber is nicely insulated, well suited for retaining cooking heat. The chamber is so effective it often does not require a large reflector to capture sunlight. The ends of the tube are open so a slender cooking tray can be inserted. Improvements in glass technology is allowing for larger diameter tubes to be fabricated, which will allow larger cooking trays to be inserted inside. READ MORE