Have you ever tasted the difference between solar-cooked corn on the cob and microwave or steamed corn on the cob?  How about tasty solar baked potatoes, mixed vegetables, or marinated chicken, beef or fish?

In recent years, many people around the world have tasted the delicious difference and are getting hooked on cooking with solar energy. And it's not just the taste that has fueled the rush to make or buy your own solar oven. Improved ease of use and portability now make many solar ovens the perfect camping, hiking or outdoor cooking companion for primary or backup survival use. Even everyday use at home is now possible with some commercial ovens.

Solar cooked vegetables taste more like crock pot cooked food.

Third world countries around the world have made solar ovens a necessary appliance in their communities for years because they have little or no local natural fuel supplies such as wood and oil, or because the price of imported fuel is unaffordable. Solar water pasteurization has made foul water drinkable for many poor nations, thus reducing death and disease in large numbers.

The use of renewable energy products such as solar ovens is expected to increase dramatically in the new millenium, as fuel prices and population numbers continue to rise around the world. Even the U.S. government has begun to designate billions of dollars of funding for the development of new renewable energy products to be sold around the world.

Destined to become a household appliance

Will solar cooking ever transform from it's "novel science fair" status into a "necessary household appliance" status in the United States and other large countries? It seems more possible now than ever before, because of the introduction of lightweight space-age products and raw materials. Unbreakable clear polycarbonate plastic; a new highly-reflective solar reflecting material called "ClearDome SolarFlex"; and new low-density insulating materials are stimulating more interest and bringing down the high costs of making durable and portable solar cooking devices for the masses.

There are currently only a handful of solar oven manufacturers in the world, and the better-known solar oven companies are in the United States, where raw materials are less expensive and easier to obtain. The most popular large solar ovens are priced in the $80-$300 range and are the traditional box ovens or focused mirror parabolic design. They weigh at least 20 pounds or more and must be moved once or twice an hour to the moving sun.

Cost used to be associated with high heat levels, until the introduction of new lightweight reflecting materials and new ways to capture the heat for cooking the food. Now, some commercially produced lightweight solar ovens and reflectors can cost as little as $10 and heat nearly as hot and fast. A quick search on the Internet under "solar ovens" will yield a number of websites that sell and design solar ovens and reflectors. Look for ClearDome Solar, the Sun Oven and the International Solar Cooker's Cook Kit, for example. Assembly plans and user groups can also be easily found at these or other solar oven websites.

Four key components to solar cooking devices

The key components to a typical solar oven are: the reflector, the heat absorber, the insulation and the cooking container. The more visible and invisible (infrared and ultraviolet) solar energy reflected, the faster and hotter the food will cook. High levels of heat absorption also adds to faster, hotter cooking. Without sufficient insulation, the heat will escape. And a black or clear cooking container such as a black metal pot or clear polycarbonate, or glass containers work the best for holding food while cooking.

Most home solar oven builders use household heavyweight aluminum foil or shiny Mylar plastic for their solar reflectors, costing about $3 per roll. It's usually taped or glued to cardboard or flat wood. It is, however, very easy to tear, and breaks down after only a few uses if mounted on cardboard. Larger sheets of metal can cost much more, weigh more, and are not as easy to cut or form. Most metals, glass, and Mylar, are generally less reflective than aluminum foil or Mylar. Reflectance levels of these materials and mirrored glass is in the 75-80% range.

Presently, the most reflective surface available to solar oven builders is ClearDome SolarFlex, a tough, flexible reflecting material that can be used for all types of solar oven construction. It costs around $17 for a large 48" by 24" sheet, it weighs only eight ounces--and is almost 20% more reflective than aluminum foil or glass mirrors at 97.4%. It can be formed over wire or tubing, and can be glued to any surface. And it vey difficult to tear, and is waterproof, so damp environments will not ruin the reflector. Free samples of SolarFlex are available at: www.cleardomesolar.com

Three main types of Solar Cooking Devices

In a traditional box oven, the inside of the oven and the enclosed black food container act as the heat absorber. Solar energy enters through a glass lid at the top of the box, surrounded by flat or curved reflectors that redirect and multiply the incoming sunshine. Most box ovens have black metal or a reflective surface such as aluminum foil lining the interior of the heating box. A layer of insulation surrounds the sides and bottom to retain the heat. Preheating the box is suggested to speed cooking times. And, constant adjustment to the sun is necessary or shadows will begin to cool the food. Box ovens were first made a few hundred years ago.

Typical parabolic dish reflectors generate very high heat levels from a single concave surface mirror that acts like a large magnifying glass, concentrating solar energy on the side or bottom of the cooking container. A smooth mirrored surface will produce extremely hot and bright spots of heat that act like an intense electric hot pad. Caution must be used, however because the heat is so intense and will easily burn the user or the food, and the sharp, focused light can be dangerous to your eyes if the dish moves away from the food container at the focal point. The parabolic dish must be moved to the sun three to four times any hour, and food must be properly secured to prevent spillage when the dish is adjusted.

The new ClearDome Solar-design Square Parabolic reflector incorporates the best of both of the above types of ovens with a very hot, but safe diffused parabolic design. Instead of a box to contain the heat, clear containers or black metal containers absorb solar energy from both the outside and inside at the same time when a clear lid is used. The parabolic form concentrates solar energy into a hand-side area blasting the side and top of the cooking container with intense hea. Instead of a sharp, single focused ray of light that can burn and needs more constant adjustment.

 By adding an additional outer  polycarbonate or glass container, or an oven heating bag, the heat is trapped inside the oven container and builds rapidly. Insulation is provided by the containers and layers of dead air between the containers. No preheating is necessary and cooking heat levels match or exceed most of the other types of ovens. Interior dry container heat can build to over 350 degrees F in only 5 minutes of midday sun. There are also many variations of these three basic designs being made by home solar oven builders.

Solar Cooking is free, non-polluting, and the most natural way to make possibly the most delicious hot food you'll ever taste. And just think, when the power goes out you'll still be able to make a hot, tasty meal!

For questions or comments, please call solar heating designer Deris at 949/233-4747 or 858/587-1377 in San Diego, visit our homepage at: www.cleardomesolar.com,  or send your email to: hotfood@cleardomesolar.com
 

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