The Octagon Parabolic Solar Cooker made by San Diego, California's ClearDome Solar Thermal will soon be the newest Solar Cooker on the market. It's expected availability in late August 2007 is eagerly awaited. I had the unexpected luck and good fortune of very recently meeting it's designer, Deris Jeanette (pictured here cooking in his prototype Octagon Cooker) who happened to be visiting his daughter's family just several miles from my own home, in North Idaho - which shares the same latitude in the US Pacific Northwest with Seattle.
The Octagon Cooker made an immediate impression on this Solar Cook. For one, it's all reflector - with more surface area and being noticably more reflective than either of the Panel Cookers I own - those being a CooKit and one of it's design variations, a South African SunCatcher. Because of the Octagon Cooker's innovative design, despite it's appearance, it's not a Panel Cooker at all but actually an eight-sided, single piece parabolic constructed of ClearDome Solar's amazingly reflective AA (coated anodized aluminum) Panel, an exceptionally reflective (95.5%) polished aluminum metal sheeting of European import made to ClearDome Solar's own research specs to maximize direct ray reflection and minimize scattered optical ray diffusion - it sports a front and back transparent overcoating of anti-oxidizing weatherproof/UV protectant that gives a minimum of 5-7 yrs of outdoor life with an expectancy of up to 20 years of exposure to the elements. It's also unaffected by corrosive salt water seaside use.
The Octagon's geometry and reflector composition directs Sunlight at the Cookpot and does not errantly scatter light away from it's heatsinked base plate. The heatsink itself is an 11" X 8 1/2" piece of 3/4" lightweight fiber and concrete mix standard house siding sprayed flat black with hi-temp BBQ paint - it's adhered to and temp-isolated away from the Octagon's base plate with Silicon-2 caulk (because it's non-outgassing) which works well. The Octagon's wrap-around structure only requires repositioning infrequently - up to 2 hours of unattended cooking is possible as sunlight is passed around inside it's circular reflector, however I couldn't keep myself from attending this beautiful Cooker much more often than that as it most resembles a piece of dazzling sculpture. Cooker sun orientation is accomplished by arranging for a hands-width of shadow along it's base's left edge, then pivoting the reflector on two baseplate wingnut bolts forward or back until the cookpot is maximally illuminated. The reflector can be tilted far forward for early morning or late afternoon and low-azimuth winter/high or low latitude cooking and back to it's middle or back slanting swing range for the middle "shank of the day". "Fine tuning" of forward-and-back cookpot placement within the Octagon Cooker can be accomplished by extending a finger over the top of the reflector's back and looking for a finger shadow down below in front of the cookpot. Just making sure the cookpot isn't partly shaded and fully in focused light is sufficient though.
For Cookware, glass-lidded standard stovetop pots and frying pans are used - the usual black thin walled aluminum or sheet steel cookware proviso for Solar Cooking is of course still recommended for quicker cooking. The Octagon Cooker will accommodate standard kitchen cookware 11" wide and nearly a foot in height (not counting a tight fitted domed glass lid), though food cooks hotter and faster in shallower pots, like sauce pans and skillets which present less thermal mass to heat. There's cutouts in the front and back of the Octagon Cooker that lets you pass a handle of a frying pan out beyond the Cooker. A glass-lid Cookpot is itself the "Oven" - the Octagon's design makes usual cooking a "No Oven Bag" Solar Cooking system.
That's because the Octagon features large reflective surface area (6 sq. ft.), it's very reflective material, heatsink and circular geometry. Designer Deris Jeanette explained that sunlight is a roughly half-and-half mix of long wave visible light and invisible infrared heat wavelengths (the balance is UV which amounts to only about 3% of sunlight's spectrum and the bulk of sunlight potential damage to reflectors - the Octagon is UV protected), so his Octagon Cooker is designed to take advantage of most of sunlight's spectral range, which is why the Cooker uses glass-topped cookware, taking advantage of light focused from above through the pot's lid as well as directed to all sides of the cookware.
An extra oven cooking bag or ClearDome Solar's optional clear polycarbonate domed pot cover will reduce solar irradiation by 8-10%, but may be helpful in maintaining heat in steady wind conditions and on cold days. I found reheating a dark mug of coffee was easily done by just covering the top with a piece of clear kitchen wrap and setting it into direct light in the Octagon. I could begin cooking a rice and vegetable casserole before 8 AM this morning. Octagon's designer Deris Jeanette cooked us several nice boneless Chicken fillets in a Chipotle chile sauce for lunch in about an hour, earlier baking potatoes before noon, placed dry in a glass-topped pot.
The temperature check below shows the chicken after 45 minutes of solar cooking. In another 20 minutes the chicken temperature reached 165 degrees F, ready for eating. Many clear glass lids normally have removable plastic handles that allow for temperature checks though the hole in the lid so the cover does not need to be removed.
An option is an unbreakable clear Solar Still container will be also soon be offered for the Octagon - making it a first for any commercially available Solar Cooker. The distilling unit can batch distill ultra-low particulate pure H20 (4-5 times less particulates than bottled water) from salty and brackish water or from any fresh water source, having an output of 2-3 cups/day. Interesting and useful pure fragrant essences of any herb or spice can be easily produced when placed in H20 or ethanol alcohol for distillation in the Octagon Cooker's Still. Any Wine can be distilled into quite drinkable Brandy as well which incidentally can be included as a flavor ingredient in some Solar cuisine. Interesting possibilities for Solar Still experimentation naturally come to mind. Incidentally, the Still can also be used to bake bread. That's versatility.
My delight in viewing this pre-release Solar Cooker was complete when ClearDome Solar's Designer Deris Jeanette offered to sell me one of his (coveted by many) prototype Octagon Cookers, which I'm happily putting to daily use. Expected pricing for the Octagon Cooker will be USD $189, plus shipping and it's later release Solar Still's yet undetermined price may be about $50-75. Other accessories will be upcoming periodically in the development cycle, including a 1-gallon crock pot option that gives the solar cook an easy way to keep on cooking using low wattage wall power when clouds unexpectedly cover the sun. When sun energy goes away, the black cooking crock is lifted out of a clear polycarbonate insulating container when on the Octagon cooker, then placed into the 120 volt AC-powered standard crock pot heater in your kitchen. The AC low wattage (100-190 watts) slow cooker unit remains inside, and the black cooking crock becomes a hybrid solar/AC cooking container.