Cookin' with Sunshine Ed Eaton In just a few days, the sun showers us with energy equal to all the earth's fossil fuels. Consider our environment and its condition; using solar energy seems only logical. One way to use the sun is to cook with the solar energy. We can bake, fry, steam, or even solarque our favorite dish right in our own backyard. Brief History Successful solar cookers were reported in Europe and India as early as the 18th century. The increased use of glass during that period helped inventors to trap heat & hot air. In 1870, Augustine Mouchot invented a fairly portable oven for the French Foreign Legion. It could bake a pound of bread in 45 minutes or 2 pounds of potatoes in one hour. Around the same time, W. A. Adams developed an eight-sided mirrored oven which reflected light through a glass cone located in the center of the oven. This oven could cook a 12 pound turkey in 4 to 5 hours. This is still a popular design today. We actually use a large model, very similar to Adam's oven. In this oven we can cook 60 pounds of food at a time Present Times Interest in solar energy seems to fluctuate along with the price of fuels (oil in particular). We feel a new awareness is blooming. It is due to the ever growing concerns about OUR planet EARTH and our desire to help Earth out! Solar cooking enables us to contribute in a small, simple way. How It Works Sunlight is concentrated in a cooking area by using mirrors or any reflective surface. Consider a car parked in the sun with all the windows up. The sunlight is absorbed as heat by the car's interior. The rolled up windows help keep the heat and hot air within the car. In solar oven heat is captured inside an enclosed area and is absorbed by the food and pots or pans. This is called the greenhouse effect and applies to cars, solar cookers and planets. In solar ovens, temperatures as high as 425¡F can be achieved. INSERT ILLUSTRATION Methods of Cooking Ovens come in may shapes and sizes. For example there are: box ovens ¥ slant-faced ¥ multi-mirrored ¥ four sided pyramids...... This list could go on forever. INSERT ILLUSTRATIONS Designs vary, but all OVENS trap heat in some form of insulated compartment. In most of these designs the sun actually strikes the food. It is pleasing that the sun's energy is absorbed by the food we eat. Cookers or hot-plates reflect light to a focal point. Just the same as a magnifying glass. They are used for frying or by holding the food in the focal point (like a hot dog on a stick). Use caution with a cooker, especially when children are around. Intensified light can cause fires, burns and be harmful to the eyes. Steamers work just like they sound. The cooker's heat boils water to make steam, which cooks the food. I have seen designs that are just a solar hot water collector. Simply directing steam to a box with a relief valve on it. Just like a pressure cooker, except the sun provides the power. Our Favorite The Slant-Faced Oven. We use 3 of these, along with other designs. One nice feature of this oven is it works in the winter. For the avid solar cooker, this is essential to roast the Christmas turkey! Its ease of construction is nice too. You can vary from the design readily, so you can use available materials. The oven is fairly portable and very durable. The compartment size can be nice and big too. This design is capable of exceeding 400¡F. They generally cook at 325¡F to 350¡F. INSERT ILLUSTRATION Important Facts ¥ There are some important facts to know when building a solar oven. One is to: GO FOR IT. Don't be afraid to experiment. That is how progress is made. ¥ When choosing insulation, be sure to use insulation that will not out- gas. Ask your supplier if the insulation can handle high temperatures. Some will actually break down at 250¡F and lose their insulation capability. Stay away from ALL foam type insulations. We recommend duct-board insulation. It made of pressed fiberglass with strong, waffle- like foil on one side. Regular fiberglass insulation works fine also. Just be sure to cover it some how, insulation tastes horrible. ¥ Paint the inside of your oven black with non-toxic, lead free paint. A good paint is equal parts of black tempera powder, white glue and water. Simply mix together and brush on. ¥ Use dark cooking containers. Stay away from shiny pots & pans which reflect light instead of absorbing it. We use cast iron pots with glass lids. Cast iron cooks well and retains heat. With the glass top, you actually have an oven inside of an oven and you can see your food cooking. ¥ Cooking bags can be used for those bigger foods, such as turkeys, roasts, etc. They are very durable and can be purchased at most markets. Be sure not to tie these real tight as they expand when the heat can't escape at all. ¥ Good reflectors are very important. Make your reflector surface as large as the area you are reflecting into. Reflectors can be made out of aluminum foil, reflective mylar, glass mirror, polished aluminum, stainless steel or any item that reflects light well. We use mirrors because you can clean glass easily and repeatedly. This is a strong point, although they are cumbersome for portable ovens. Try to use at least double strength glass. Lighter glass seems to crack when cooling down. Leave room for the expansion of your glass. A metal liner for the inside of your oven is a good idea, it retains heat and keep spills in check. Our first oven had cardboard reflectors with aluminum foil glued on. This worked fine until it got wet. But by that time we had saved up for some mirrors. ¥ Our reflectors here in the southwest work very good when set 120¡ from the surface of the front glass. You might want to make a cheap cardboard reflector, like mentioned above, and see what fits your needs. ¥The front angle of your oven will differ according to your latitude. To be quite honest, I don't know how critical this is. I'm sure it does apply if your latitude is very far north or south. We in Tucson have great success with angles of 30¡ to 50¡, and in winter we use 60¡. Quick Tips ¥ Clear sunshine is essential for cooking. You can cook on partly cloudy days but it will take longer. On very cloudy days, FORGET IT! ¥ Remember the outside temperature is not a big concern. We have cooked at 9,000 feet elevation in 3 feet snow. It's the amount of sunshine that's critical. ¥ The time required will vary according to the type of oven you have and the time of day you cook. Most dishes take about the same time as a conventional oven once your oven reaches operating temperature. Preparing your dinner in the morning instead of the evening. You'll go home and eat while your friends go home and cook. All it takes is some practice. ¥ Need $ incentives? For each dollar spent on conventional cooking inside an air conditioned home, an additional three dollars will be spent cooling the house back down (according to a study done by Arizona Public Service Co.). ¥ Solar ovens are great for camping or at the beach. They use no flame and can be used in fire restricted areas. The Tucson Solar Potluck & Exhibition Nancy & I attended the 2nd Annual Solar Cookoff in Phoenix AZ in 1982. It was a great event, about 60 solar ovens in a cooking contest. The problem was that only judges got to taste all the great food. This is when my brain got in gear. Zap, we should organize an event with other solar applications included and have a BIG potluck dinner at day's end for everyone to share. Potluck attendees could sample solar cooked food and see other renewable energy applications as well. We worked hard with several close friends and others interested, writing, calling, begging, etc. Well, about 30 people set up ovens and 300 to 400 people showed up during the whole day. 125 people ate dinner! It was a big success. We had music and stories for the kids. We had PVs, hot water, solar greenhouse displays & more. I have seen cooking devices made from the most unbelievable materials. One fellow this year used three M-75 ARCO PV panels hooked up to an inductive coil inside a small insulated box. He made cookies all day. Food samples are handed out all day, the favorite seems to be our solar cooked pizza. Picture a beautiful panoramic view of the Santa Catalina Mtns, while you are nestled at a lower elevation amongst the mesquite trees. Solar ovens are everywhere, each emitting its own tantalizing smells. The sound of live music is in the air, powered by PV. People are having fun and exchanging ideas all around you. The Sun is alive and well at Catalina State Park! The Solar Potluck has grown with time & continues to thrive. Attendance has varied over the years, this year 350 to 400 people showed up. Most people come, observe and go on their way. But next year, a few of those same people will show up with some type of solar project of their own. This event is organized by a loosely formed group; citizens for Solar Cookery. We are not real formal but we get the job done. Money is not the issue here, it's solar consciousness we want to spread. There is a $2 charge to enter the park itself, but it's worth it. The park has trails, camping and represents the vast Sonaran Desert well. Obviously this event requires some money to make it happen. We never received any financial help, except for donations to cover our beer supply and through the sale of "T" shirts. This keeps us free from greed motivated interests which have different objectives than ours. We welcome all advice and especially welcome any literature, for handouts at the Potluck, that we can get. Camping is available, and we invite everyone to attend. As far as we know, this is the only ANNUAL solar event for the general public in the U.S. I hope I am wrong and strongly welcome news to the contrary. Unfortunately, the date for the 7th Annual Tucson Solar Potluck and Exhibition is not yet set. We cannot reserve the park area more than six months in advance. I promise the date will be in Home Power when we set it in December. The Potluck is to be in late April or early May. If anyone would like info on solar cooking or on the Potluck please write or call, Ed Eaton, POB 55891, Tucson, AZ 85703 or 602-325-7860. Heck, just call to talk if you want to. This article was written by one person but the story has many, many names behind it....Nancy, Ron, Karen, Tony, Chunky, Bob, The Halacy's, The Blankenships and moreÉ Peace, Ed Eaton. Good Sun Cooking Reading "The Solar Cookery Book" by Beth and Dan Halacy Peace Press "Solar Cooking Naturally" by Doris Stutzman HCR Box 305 J Payson, AZ 85541 "A Golden Thread, 2500 years of Solar Architecture and Technology" by Ken Butti and John Perlin Cheshire Books