Cooking with soul: Solar cookers

 

 

 

Solar cookers are heat-trap boxes or panels that convert sunlight to energy that cooks your food. Also called solar ovens, these inventions don’t tax scarce raw materials or pollute the environment in any way. You can purchase one at a reasonable cost for a kitchen appliance, or you can make one yourself out of simple materials easily procured at the local hardware store.

 

 

Although it might appear to be one of the latest environmentally friendly crazes, the concept of cooking food and boiling water via sunlight has been around for at least a couple of centuries.

 

Two types of solar cookers were invented in the 1950s: the direct-focusing cooker, in which a pot is supported at the focal point of a reflector in a parabolic, or similar, shape, and the Telkes oven, in which cooking pots are placed inside an insulated oven. This oven has a wall that consists of a window, usually double-glazed, that is surrounded by an array of plane reflectors. A third type invented later, the indirect cooker, is usable indoors and during the evening.
 

 

The direct-focusing cookers are typically the least expensive to build, and they achieve the fastest cooking times, at least for small quantities of food. They lend themselves best to do-it-yourselfers. The skills needed to build most of these cookers include basic sheet metal bending, cutting, welding and drilling holes.

 

If you aren’t the “do-it-yourself” type, many designs are available for purchase, including high-quality, sturdy versions that are very easy to use, like the Global Sun Oven, available at Solar Cookers International (SCI). Inexpensive types are also available for purchase, like SCI’s CooKit, which folds down to a roughly 1-foot square. It can cook two pots at once and is perfect for camping.

 

Telkes ovens are much more expensive and challenging to build. Aside from the large reflector area and two large pieces of glass for the window, the oven requires both inner and outer sheet metal boxes, high-temperature insulation and a door. Compared to direct-focusing cookers, however, these ovens are easier to use and cook greater amounts of food, while keeping their contents warm and protecting them from blowing dirt and wind. Telkes ovens can also operate for long periods without maintenance.

 

The direct-focusing cooker uses a reflector to focus sunlight directly onto a dark cooking pot, which is either suspended or set on a stand at the focal point. The cooker consists of one or more reflectors and a framework that supports both the reflector and the pot. Numerous arrangements of this cooker have been devised to allow the reflector to be tilted to always point toward the sun, with the pot remaining at the focal point.

 

Sunlight is gathered by the reflector and siphoned into the panels of the solar cooker. The sun’s rays are converted to energy focused on the cooking pot in the center.

 

 

You can set up your own solar cooker on a platform in an outdoor area, garden or porch that gets direct sunlight. Optimal usage takes place between 11 a.m. and 3 p.m., a decided drawback for the full-time commuter, but doable for the telecommuter at home and for all home chefs on weekends, holidays, or days off.

 

Since direct-focusing cookers use only the sun’s direct rays, they work poorly on hazy days, and a cloud passing overhead will temporarily “turn off” the cooker. They are not dangerous to leave unattended, but care must be taken to adjust them to face the sun every so often. This can be from every 20 minutes to once an hour depending on the model being used.

If you have children, this is the perfect item to use to introduce them to basic solar energy science. They can assist you in the construction and in the cooking process, and then taste the outcome. 

 

 

Although direct-focusing cooker designs offer good performance at comparatively low costs, they have a number of shortcomings and special design considerations:

 

 

Solar cookers have been available for purchase in the United States for the past 30 years or so, but their international purpose is much more urgent. Aid organizations are providing these items to developing countries including where the poorest inhabitants can scarcely gather enough firewood to cook their meals because of deforestation of the area they live in. They are also distributing them to refugee camps in Kenya, Ethiopia and Chad, with great success. The smoke-free, pollution-free and energy-free appliances offer great benefit to the people of these regions.

 

 

To learn more about Solar Cookers, you can visit the following Web sites:

 

www.solarcookersinternational.com - View various models and obtain designs.
www.solarcookers.org - Read up on how to make your own.

 

There are also a number of books on solar cooking available:

“The Expanding World of Solar Box Cookers,” by B. Kerr 
“Sol Food: A Primer/Cookbook,” by H. Kofalk 

For information on solar oven construction, try:

"Solar Cookers: How to Make, Use and Understand,” 9th Edition, SCI