HISTORY
Solar box cookers (SBCs) are the earliest form of solar cooking in Western culture. An early European record of cooking in a solar box was made by Horace de Saussure, a Swiss naturalist experimenting as early as 1767. He reported successfully cooking fruits at that time with initial temperatures of 189.5 F (87.5 C). Over the years, de Saussure and others focused their solar box cooker design work on variations of shape, size, sidings, glazings, insulations, reflectors, and the composition and reflectance of the internal surfaces.
These components have been varied endlessly in an effort to increase solar box temperatures. Our solar boxes now successfully reach temperatures between 275 -300 F (135 -149 C), depending on size and location of use. Since many foods will cook with an internal temperature of 190 F (88 C) and water boils at 212 F (100 C) at sea level, it is clear that solar box cookers have reached adequate cooking temperatures for a long time.
Meanwhile, the higher temperatures of cooking over fire have continued to force us to stir foods and protect them from scorching from excessive bottom heat, while needless amounts of fuel and human labor have been unnecessarily used. Now, we can do better than that by using readily available, free solar energy whenever the sun shines.
At the time I was first exploring solar cooking, my home was dedicated to developing Earth-Conscious Homemaking. I was exploring all the ways that could be used in an urban home to reduce consumption of earth resources. As a part of this effort, I made and used a lot of solar cookers. At one time I had seven different types of solar cookers and some duplicates in my back yard. Most were homemade. There were various parabolic and non-parabolic troughs, one five foot dish parabolic concentrator, and several four-reflector slant-face ovens—one made from the Halacy plans. There was the beautiful octagonal Solar Chef designed by Sam Erwin. Almost daily, neighbors and friends would join me for potluck dinners using the solar cookers.
When I put together my first solar box cooker in March of 1976, I had simply heard that an Indian designer, Ghosh, had made a solar box that cooked, but I had not been able to obtain plans or illustrations of it. Unaware that it "should" be made of metal or wood, I used cardboard boxes and thus opened a new line of SBC development. Had I been more knowledgeable, I would not have been so surprised that it cooked very well, if somewhat slowly, at its initial temperature of 240 F (115.5 C). With improvement in the thermal dynamics of the box, 300 F (149 C) was reached, a more than adequate temperature for boiling, roasting, baking, and gentle frying...surely a solar kitchen range.
During June and July of that year, Sherry Cole, my good friend and neighbor, and I faced a definitive test for solar box cooking. We had a large social action group in our homes. In addition to office and sleeping space, we offered to provide meals for the volunteers, planning to use the backyard solar equipment as much as possible.
Meeting the daily food needs of 35 to 40 hungry adults presented a perfect opportunity to compare the practicality of the various solar cookers. It provided fine tests of comparative function under stress. Our choice of cooking apparatus gradually shifted away from the multiple reflector and parabolic cookers to solar box cookers. While we initially had been aware of some of the special qualities of solar box cooking, it was through the routine serving of large quantities of food that the major strengths of the solar box technology emerged. They reliably cooked large quantities of food but required minimal attention. With a hectic schedule, it was not possible to give focusing cookers the attention they required. When attention lapsed, the focusing collectors would go out of focus and the food would not be done when needed. In addition, little gusts of summer wind would close or topple the multiple reflector cookers—again resulting in partially cooked food. But if food was placed in a solar box cooker early in the day, we were assured cooked food at mealtime.
Our parabolic and multiple reflector cookers came to be used only for foods requiring shorter cooking or warming periods, preferably while someone was close at hand to tend them. They ended up being used mainly for optional dishes, while solar boxes became the workhorses for cooking the main dishes. An additional solar box cooker or two would have done as well or better at meeting our needs than my yard full of the more intricately designed cookers. When using solar box cookers, once the food was in I could give full attention to other chores. In addition, on the few semi-cloudy days, food in the SBCs cooked much better than food in the cookers that depended more heavily on reflectors.
Although solar boxes have been used for home heating, water heating, and distilling, the box design has not yet been widely used for cooking. Perhaps this is because solar boxes are so unassuming; it is hard to jazz up a large, simple box to appeal well in advertising. It needs to be seen in action to be believed. But solar box cookers have clearly demonstrated their effectiveness when it comes to meeting food service needs whether it be for individuals or groups, households, schools, businesses, or other organizations.
Sherry Cole identified the widespread value of such a device. We joined forces to tell as many people as possible about solar box cookers. As the effort began to attract media attention, we had a string of visitors, including several from the engineering department of the nearby university. Earnestly and with all good intent, I was advised to drop the solar box as it was an inherently inefficient design. One good-hearted engineer sat next to a solar box that was quietly and cheerfully cooking a large pot of beans and told me that "solar boxes just won’t cook," and proved his point by referencing a scale in a technical book he had brought along!
This experience made it clear just how different our design goals are from engineering approaches. Engineering approaches and available literature often emphasize maximum solar collection at the expense of simplicity, functionality, appropriate materials and ease of use. Such designs do not lend themselves to being used as routine home appliances, nor can they be built without special tools and skills. Our design goals emphasized simplicity in design and construction easy for nonprofessional builders, the use of appropriate and available materials, ease of operation, and dependability under a wide variety of conditions. Our cardboard designs assumed the use of recycled materials and minimal additional costs.
After it became known that Sherry and I had experience with inexpensive solar box cookers, we were approached by two elementary school teachers. They wanted us to produce a lightweight teaching model made of cardboard that could be taken apart and reassembled repeatedly by third grade students in a special gifted program. They wanted a teaching device and a good cooking unit combined. This work led to the development of the patented Kerr-Cole Solar Box EcoCooker and the production of kits and complete stoves. Although designed for maximum simplicity, the EcoCooker design proved to be a useful teaching tool for all age and educational levels. We received both national and state energy innovation awards on this work.
While we did make wooden models, and still sell plans for a wooden design, the cardboard designs have been most popular. To allow viewers to see the construction details, the teaching model boxes can be completely disassembled. They can then be reassembled in a few minutes to start cooking.
In 1978 Dr. Robert Metcalf, an early SBC user, identified the SBC as a potentially powerful tool for public health efforts to reduce microbiological illness, and as a component for many environmental and social efforts from nutrition projects to tree planting efforts and more. With the full support of his Department Head, he has used his degree in microbiology and his position as Professor of Biological Sciences at California State University Sacramento to lay the scientific base for major expansion of SBC usage. Studies done with his students established the safety, microbiologically, of solar box cooking and the feasibility of water pasteurization by means of SBCs. With the safety of cooking and pasteurization scientifically established, Dr. Metcalf has spoken to thousands and has given hundreds of demonstrations to the academic and environmental community. He has spent private funds to travel to Washington, DC and elsewhere to speak to and demonstrate the solar box cooker for key people in government and private volunteer organizations. He and his wife have opened their home to travelers from all over the world coming to see the incredible cooking box.
Dr. Metcalf has donated hundreds of hours of his private time to give speeches and demonstrations. He interested Dr. Fred Barrett of the United States Department of Agriculture and together, with funds from US-AID, they prepared a video, "Four Square Feet of Sunshine," which introduces the concept of solar box cooking and its potential benefits. He also had a major role in preparation of the video, "A Bright Future." He recruited numerous friends, including Dr. William Sperber, from the Pillsbury Company, a company which provided funding for an SBC project in Bolivia as a part of an Applied Nutrition Program with the Freedom From Hunger Foundation. Together with an anthropologist, Dr. Aaron Zazueta, and local Aymarans, in March, 1987, they walked out beside potato fields on the altiplano of Bolivia and held the first international solar box cooker demonstration focused on technology transfer through the use of a functional cardboard model.
Dr. Metcalf also interested Leland Brenneman of PLAN International, formerly Foster Parents Plan, and worked closely with him as well as Dr. Sperber during a second Pillsbury-sponsored international project which was held in El Progreso, Guatemala in January, 1988.
Although the work by Sherry Cole and myself was progressing, it became clear that many more resources were needed to spread the knowledge and practice of solar box cooking. SOLAR BOX COOKERS INTERNATIONAL (SBCI) was formed in 1987 as a non-profit volunteer organization to respond to inquiries and provide central coordination of volunteer donations of time and money, develop educational materials, and promote knowledge of the technology and use of SBCs worldwide. Our goal came to be to make solar box cooking as widely known as cooking with fire. SBCI publishes a newsletter covering the broad aspects of what is happening in the SBC field. Their work is closely coordinated with SOLAR BOX COOKERS NORTHWEST (SBCN). Formed in 1989 in Seattle, SBCN publishes a fine quarterly newsletter specifically on solar box cooking, with reports on SBC activities around the globe. SBCN also coordinates an on-going international computer conference on EcoNet dealing with appropriate technology in general and SBCs in particular. Through these organizations, numerous volunteers with a broad spectrum of skills and professional qualifications have donated hundreds of hours of work. Through their efforts in providing workshops and literature, information on SBCs is now moving out to people all over the world.
The educational materials that SBCI has produced, which are available from their office, have greatly multiplied the effects of individual volunteers in the spread of knowledge about solar box cooking. But perhaps their most important contribution to date has been development of a training system and a workshop outline with materials to assist individuals in teaching others how to build and use SBCs to cook with the sun. These organizations deserve all possible support.
Information on other solar cooking efforts in many locations and with diverse designs has been gathered and published by the German Appropriate Technology Exchange. It appears at this time our effort is the one most heavily focused on technology transfer.
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