"Light, compact, durable and inexpensive" is the way Roger Haines of San Diego, California, USA describes his "open source" Haines Solar Cooker. For only $15 USD per cooker, entrepreneurs in Nairobi, Kenya, and San Diego, California can buy materials to make Haines Cookers to sell for $36. Roger's Rotary Club distributed 291 solar cookers in Nairobi in 2013 and found that, on average, solar cooking saved $9 a month in firewood costs. So a $36 cooker will pay for itself in 4 months and yield a $9 profit every month thereafter. The buyer can "pay from the profit, not the pocket."
Instead of cardboard and foil, the Haines reflector is made of MPET (metalized polyester) film bonded to 3mm of IXPE (cross-linked polyester) foam, with a white PET film backing. The reflective polyester will not oxidize, cannot be scratched off, and has a high melting point. Importantly, the new material is easy to recycle and is environmentally safe through the whole production and recycling process without pollution. In the U.S., this material is used to make high-end auto windshield sunshades that last more than 10 years.
The reflector is a 60 cm. x 120 cm. (2' x 4') rectangle of reflective material, with three cuts. Overlapping the cuts as shown produces a flat bottom and a parabolic shape, secured with a single brass fastener inserted through grommet holes. The cooker sits solidly on the ground and withstands strong winds when secured by a string passed through holes in the bottom of the cooker. When the sun is low, the front of the cooker can be tilted down to catch more sun.
The cooking sleeveEdit
Because disposable plastic "oven bags" are expensive and awkward, Roger designed a permanent "cooking sleeve" to insulate the cooking pot while keeping the lid accessible during cooking. The sleeve is a 6" x 48" rectangle of UV-resistant 0.5 mm. clear polycarbonate film. rolled into a cylinder that is adjustable to fit any round cooking pot that has a top rim and no handles. The top rim of the pot rests on the top rim of the cooking sleeve, elevating the pot so that the sun's rays can be reflected onto the bottom of the pot. Roger has found that a glass lid works best because it retains more heat.
A circular windscreen keeps the reflector rigid in the wind and creates "oven-like" conditions around the cooking pot. The windscreen is made from a 30 cm. (2-foot) diameter circle of 0.5 mm (.020-inch) UV-resistant polycarbonate film. For increased rigidity, a radius cut is overlapped two inches to form a flat cone like a sun hat. The overlap is secured by a string connecting grommet holes in the windscreen and the reflector. To access the pot, the windscreen can be moved to the side, as shown in upper left of the photo.
Shipping and storageEdit
For shipping and storage, the cooker rolls into a cylinder 60 cm (24") long and 10 cm. (4") in diameter, weighing 0.5 kg (1.1 lbs).
Recent news and developmentsEdit
- November 2014: Solar Cooker Business Opportunity. Roger reports that a prominent Nairobi, Kenya building supply company is now selling materials to make "open source" Haines Solar Cookers for $15 per cooker in wholesale quantities of 50 or more. Contact Nishal Sodha at Global Hardware, Ltd., a subsidiary of Elgon-Kenya (http://www.globalhardware.co.ke), telephone: +254 20 2399998, +254 20 2399998/7. Cell: +254 786 456 225; E-Mail: email@example.com. Finished cookers and training are available from Faustine Odaba, director of the Nairobi NGO, NAREWAMA. Telephone: +254722828317; Email: firstname.lastname@example.org. Materials for 500 cookers have been delivered to the Rotary Club of Gulu, Uganda, and plans are being finalized on a partnership between Rotary and a prominent microcredit lender to provide $250,000 USD in microcredit loans to entrepreneurs to sell Haines "open source" Solar Cookers in Kenya.
How to Make a Haines Solar CookerEdit
Making the reflectorEdit
1. Make a template from a 60 cm. x 120 cm. rectangle of thin material using a saw to make 3 cuts, and drill 6 small holes "B" and "C" as shown. 2. Lay a large piece of plywood on a table. 3. To "guide" the material, attach a length of 2 cm. square wood to the plywood, exactly 60 cm from and parallel to the bottom edge, and another piece 124 cm. (four cm. longer than the 120 cm. template) from and parallel to the right edge of the plywood. 4. Unroll 120 cm. of material onto the lower right-hand corner of the plywood, and line it up with the "guides 5. Lay the template on top of the reflective material and line it up with the "guides." Use a utility knife ("box cutter") along the right side of the template to cut 120 cm. of material off the roll, and to make the three cuts along the bottom edge. This will cut grooves into the plywood, but that is okay. 6. Use a black pen to MARK the 7 holes on the reflective material. Lift the template. Lay a small stiff template on the "fold" lines, and FOLD the material, allowing it to unfold. 7. Move the material to another table, and use a grommet tool to install GROMMETS at the 7 marked places. 8. Put a brass connector through the hole in short middle section, pointing up, and spread the two sides apart.
Making the windscreenEdit
1. Cut a flat square or circle of plywood or fiberboard at least 65 cm. on a side. 2. Put a nail through the exact center, so that the nail protrudes at least 3 cm. 3. Take a 3 to 5 cm. square of wood, about 35 cm. long. Screw a box cutter blade to the end as shown. WARNING: put tape over the left part of the blade for safety. 4. Drill a hole slightly bigger than the nail approx. 29.75 cm. from the blade. 5. Take a sheet of 60 cm. x 120 cm. clear polycarbonate film. Treat as two 60 cm. squares, and drill a hole at the center of each 60 cm. square, the same size as the nail. 6. Lay the polycarbonate sheet on top of the flat plywood, with the nail through one of the drilled holes. 7. Put the piece of wood with the cutting blade on top of the sheet polycarbonate, with the nail through the hole in the wood and the cutting blade down. 8. Press down on the wood so that the blade cuts into the polycarbonate, and rotate 360 degrees to cut a clean circle. 9. Use scissors to make a "radius" cut from the edge to the center. 10. NOTE: The sheets come with protective film on both sides. REMOVE this film now. 11. Use the grommet tool to attach a grommet 1.5 cm. from the radius cut, a second grommet 6 cm. from the other side of the radius cut, and a third grommet 180 degrees opposite, on the other side of the circle. 12. Tie 42 cm. lengths of braided string to the two opposite holes.
Making the cooking sleeveEdit
The cooking sleeves come ready-made as 16 cm. x 120 cm. sheets. However, the protective film on both sides must be removed.
Early design prototypeEdit
The original Haines Solar Cooker was designed in 2013 by Roger Haines of San Diego, California USA. This first Haines cooker was made from reflective bubble insulation sold "off-the shelf" at Lowe's Home Centers in 4-foot by 25-foot rolls. The cooker was made from a single 48" by 48" rectangle of bubble material, and required only three cuts with ordinary scissors for cooker assembly.
- See Roger Haines.