Last updated: November 23, 2015
"It boils water 50% faster than any other panel or box cooker," says Roger Haines of San Diego, California, USA, based on his side-by-side tests comparing the Haines Solar Cooker with seven other commercial panel and box cookers. According to Roger, the Haines Solar Cooker heated a liter of water to boiling in about an hour, while the next-best cooker took an hour and a half. and some cookers did not reach the boiling point at all. Successive tests were conducted in Del Mar, California on several calm days in August, 2015 with ambient air temperatures around 25 °C (77 °F). For the full report, go to http://www.hainessolarcookers.com/test-results.
Haines Solar Cookers are available in the U.S. at www.hainessolarcookers.com, but outside the U.S., the design is "open source". 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. A new Rotary project, partnering with Washington D.C.-based Solar Household Energy, is facilitating the manufacture and sale of Haines Solar Cookers in stores in Nairobi by the Kenya-based NGO, NAREWAMA,
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 sleeve
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" (15 cm. x 120 cm.) 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 cover keeps the reflector rigid in the wind and creates "oven-like" conditions around the cooking pot. The cover is made from a 60 cm. (2-foot) diameter circle of 0.5 mm UV-resistant polycarbonate film. For increased rigidity, a radius cut is overlapped 7 cm (3 in) to form a flat cone like a sun hat. The overlap is secured by a string connecting grommet holes in the cover and the reflector. To access the pot, the cover can be moved to the side, as shown in upper left of the photo.
Shipping and storage
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 developments
- 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: firstname.lastname@example.org. Finished cookers and training are available from Faustine Odaba, director of the Nairobi NGO, NAREWAMA. Telephone: +254722828317; Email: email@example.com.
How to Make a Haines Solar Cooker
Making the reflector
- 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.
- Lay a large piece of plywood on a table.
- 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.
- Unroll 120 cm. of material onto the lower right-hand corner of the plywood, and line it up with the "guides
- 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.
- 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.
- Move the material to another table, and use a grommet tool to install GROMMETS at the 7 marked places.
- Put a brass connector through the hole in short middle section, pointing up, and spread the two sides apart.
Making the cover
- Cut a flat square or circle of plywood or fiberboard at least 65 cm. on a side.
- Put a nail through the exact center, so that the nail protrudes at least 3 cm.
- 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.
- Drill a hole slightly bigger than the nail approx. 29.75 cm. from the blade.
- 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.
- Lay the polycarbonate sheet on top of the flat plywood, with the nail through one of the drilled holes.
- 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.
- Press down on the wood so that the blade cuts into the polycarbonate, and rotate 360 degrees to cut a clean circle.
- Use scissors to make a "radius" cut from the edge to the center.
- NOTE: The sheets come with protective film on both sides. REMOVE this film now.
- 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.
- Tie 42 cm. lengths of braided string to the two opposite holes.
Making the cooking sleeve
The cooking sleeves come ready-made as 16 cm. x 120 cm. sheets. However, the protective film on both sides must be removed.
- See Roger Haines.