Windshield Shade Solar Funnel Cooker While experimenting with various designs of cookers over the past year to introduce in the indigenous communities where I live and work in southern Mexico, I hit upon an utterly simple way to make an instant portable solar oven. Taking a reflective accordion-folded car windshield shade, you can turn it into a version of the solar funnel, by simply sewing on little Velcro tabs along the long notched side. Here’s how:. Materials needed:. A reflective accordion-folding car sunshade. A Cake rack (or wire frame or grill). 12 cm. (4 ½ in.) of Velcro. Black pot. Bucket or plastic wastebasket. A plastic baking bag. Lay the sunshade out with the notched side toward you, as above.. Cut the Velcro into three pieces, each about 4 cm. or 1 ½ inches long.. Hand sew one half of each piece, evenly spaced, onto the edge to the left of the notch; sew the matching half of each piece onto the underneath size to the right of the notch, so that they fit together when the two sides are brought together to form a funnel. (see below) Note: I first tried sewing these on a sewing machine, but found it cut through the reflective material.. Press the Velcro pieces together, and set the funnel on top of a bucket or a round or rectangular plastic wastebasket.. Place a black pot on top of a square cake rack, placed inside a plastic baking bag. A standard size rack in the U.S. is 25 cm. (10 in.). This is placed inside the funnel, so that the rack rests on the top edges of the bucket or wastebasket. Since the sunshade material is soft and flexible, the rack is necessary to support the pot. It also allows the suns rays to shine down under the pot and reflect on all sides. If such a rack is not available, a wire frame could be made to work as well. Note: the flexible material will squash down around the sides of the rack.. The funnel can be tilted in the direction of the sun.. A stick placed across from one side of the funnel to the other helps to stabilize it in windy weather. (see below). After cooking, simply fold up your “oven” and slip the elastic bands in place for easy travel or storage.. I have found this totally simple solar oven extremely practical, as it is so lightweight and easy to carry along anywhere. But in addition, it has reached a higher temperature in a shorter time than all the other models I have experimented with so far (I haven’t used a parabolic) - a little above 350 degrees F. I have cooked black beans in about the same amount of time as on a gas stove; I’ve used it to bake breads, granola, brownies, lasagna, all sorts of vegetables, and to purify water. The sunshade may not be available everywhere, but I suspect it can be found in most urban areas, since I found it here in southern Mexico. The Velcro was also available in fabric stores. Cost of the sunshade was about $3.00 USD; the Velcro about $.25.. Kathy Dahl-Bredine. Apdo. 1332. Oaxaca, OAX 68000. kpdbmx@gmail.com.

PLAN D - The quickie-hot-dog at the ballpark cooker for your friends and family to marvel at just how clever you are.

The Pentagon Star Cooker I am teaching unemployed people how to make and use solar cookers in KwaZulu-Natal. We have clear winters and cloudy summers and the people I have been helping have little or no money. I developed this cooker for use here and it works so well that I felt it would be of use else ware. This is a great cooker. Out side the tropics a straight panel cooker battles on all but the best days and this cooker takes advantage of lower sun angles in morning and afternoon. Being more efficient it makes up for the odd cloud in the day. It is stable in wind and if put together with paper fasteners can fold down flat for storage. Seasonal changes are made by adjusting the side flaps up or down. Most medium sized boxes work, a short side of 350 mm to 500 mm and a height slightly more than the width works best. Four short cuts and a few simple folds is all that is required there is no waste and a whole box is used. Paint the un-foiled sections of the cooker to guard against moisture. To cook, place food in a black pot or black painted jar, place the food and container in an oven bag close up with a clothes peg and place on card board scrap in the back corner of the reflector. Now place in full sun and adjust straight into the sun by the cookers shadow. Richard Pocock Solarworks 81 Archer Crescent Manor Gardens Durban 4001 KwaZulu-Natal South Africa edufun1@iafrica.com

PLAN E - Less folds means less adjusting for movement of the sun

PLAN F - FOR FREEEZING FOGGY DAYS!

THE WINIARSKI ROCKET STOVE In the last 13 years, variations of the Rocket Stove have been built in over 20 countries. Efficiency: 12-42%. The efficiency depends on type of a heat exchanger used. Construction: Simple to construct with a number of different materials. The simplest Rocket Stove can be built with thick tin cans and wood ash (5,000 of these were built in refugee camps in Zaire). Material costs: $0-$20 US. In Honduras we made a simple refugee version of this stove for approximately $1.50 US in material costs. Life expectancy: Is 2 weeks to ten years depending on the materials used. The Rocket elbow can be made from different materials to improve its durability. We have used sand/clay (Lorena), pumice/concrete, heavy steel pipe, 430 stainless steel or special heat resistant ceramic. Currently all of our stoves in Honduras are built with this type of refractory ceramic. Each of our wood cookstoves incorporates a unique combustion chamber. This is how the Rocket elbow works: This elbow is then placed inside of a container that is filled with insulation . The container can be made from almost any material. We have used 5 gallon drums, brick, clay, cement. For insulation we suggest using wood ash or pearlite, or pumice,. Do not use massive things such as earth, sand,or cement. These will rob heat from the stove and reduce your combustion efficiency. For optimal use we recommend a 9" chimney and a 4" fuel feed magazine. The Rocket stove is an improvement over the three stone fire but it is only one part of the equation. In order to really save fuel wood we must maximize the heat transfer to the pot. This picture shows a thin piece of metal (a skirt) wrapped around the pot. This skirt forces the hot flue gases to rub against the bottom and the sides of the pots. The gap between the pot and the skirt should be about 1cm (assuming you are using an average-sized pot). In our tests, this simple heat exchanger (an old coffee can works well!) almost doubles the efficiency of the rocket stove.

PLAN G - FOR TECHIES - ADD A CHEAP TRACKER!

THE SOLAR TRACKER THE TRACKER CONTROLS The heart of the Tracking Solar Oven is the electronic control. A Very simple control may be built from a photo diode (Electric Eye) and 12 volt DC relays. Most of the parts are available at local radio parts stores. The photocell battery charger that works well is the new thin film, glass-encased type that produces 18 to 20 volts and measures only 6 inchs square. The batteries are simple AA nickel cadmium rechargeable cells in series to produce 12 to 15 volts at 50 to 80 milliamperes. The photo diode (Electric Eye) is really a photo-transistor using only the emitter and collector leads which conduct electricity in the presence of light. A simple shadowbox will shade the electric eye when the oven is focused on the sun and will cause the motor to stop. At first, the photo diode is far too sensitive. To adjust the sensitivity black silicone can be dabbed over its surface then removed with a toothpick until it responds only to direct sunlight. The reset switch will send the motor into reverse until the sunrise switch is tripped. The oven is now positioned for the next day. A wind-up 12-hour timer switch on the reset switch will allow timed cooking; it sends the cooker to the sunrise setting when done and even sounds a buzzer. Conventional solar trackers are available and can be adapted for use on this or almost any other solar cooking oven. The base should be cylindrical shaped with a flat side for the door. Since the oven is supported by the base, the material used should be strong enough not only to hold the weight of the oven but support it during high winds as well. The motor is a critical part of the design. A 12 to 24 volt DC reversible gear head motor is needed which turns at 1 to 5 R.P.M. To further slow the turning rate of the oven, a chain and sprocket with a ratio of about 3 to 1 seems to work very well for final turning speed of 1 to 1/2 R. P. M. The large sprocket should be placed on the shaft connected to the oven base between leather washers to form a slip clutch to protect the drive motor and for safety reasons.

PLAN H - HAVE-A-FEAST - COOKING HINTS!

Learn to cook with more than one jar at a time. Start with the longest-cooking food, and when it is boiling, add more jars. Learn which foods (grains, potatoes, squash, lentils, etc.and what quantities of them— you can cook in one pass, so you can cook when you are gone all day. Learn cooking patterns that fit your lifestyle. Beans: Use 2¼ cups of water for 1 cup of beans. If you boil them actively over a long time, add more water. Pintos take the longest. Grains: Most grains cook better if you preheat the water in the solar cooker for an hour or so. Use a two-to-one water-to-grains ratio. Long grain rice can be put in the cooker in cold water. Vegetables: These cook in jars with little or no water, or they can be added to beans and grains. Potatoes and sweet potatoes cook well on the rack, if lightly oiled. Otherwise, put them in jars. Winter squash cooks in its own skin. Corn on the cob steam-bakes in its own sheath. Bread: Bread cooks best in dark, one-pound coffee cans. Oil the cans. Let dough rise in the cooker without collectors attached, then add the collectors when you’re ready to bake. Bread shrinks, so it will come out of the cans with a gentle tapping when it’s done. Pizza and pies: Bake the crust first. Try jams, cinnamon rolls, cake, corn bread, cookies, and other munchies, as well. When the food is cooked, you can fold the collectors down over the glass. This provides good insulation, so the food stays hot until you are ready to eat.