Friday, January 28, 2011

No Batteries Required

Somewhere between sci-fi magazines and the Whole Earth Catalog?
Nope, quite real, but forgotten low-tech solar devices.
The second picture is of the "Umbroiler" (umbrella-shaped broiler) made by solar pioneer George Lof, who tried to market it in the 60s and 70s. The high cost of metalized fabric at the time and the convenience of modern appliances made it a commercial failure. It worked quite well cooking food using free energy since it employed the ever-reliable parabolic form to focus the sun's rays, but its delicate construction and obvious problems with cleanliness called for a more robust design. Now if old George had thought of placing a small, durable parabolic dish on every other roof for satellite television instead, he'd have had a hit. The second of the two solar homes he built was well-designed and is still going strong after all these years, but you still see very few of those around.
The first photo is a homemade solar cooker; the Maria Telkes version, designed in the 1950s, has proven itself. In terms of scale, a 30" x 30" size glass cover reportedly does a bang-up job. If you're in the mood to build one and be considered a raving nut by the neighbors, the booklet "Capturing Heat" by the Aprovech Research Center in Cottage Grove, Oregon, has plans for five stoves and ovens.
It looks like Jules Verne-era sci-fi, but the magazine cover above reflects (OK, pun intended) the interest in and success with solar power in late 19th-century France. There was a lot of sun but no fuel in the colony of Algeria, so the government asked one Augustin Mouchot to help out. He developed a portable solar oven (under 40 lbs.) for the Foreign Legion which did the job. Today such ovens are being re-introduced to Africa, Asia and Brazil. Will they ever have enough impact to limit deforestation or diesel/kerosene polluting the soil?
A passive slow cooker colloquially known as a "haybox" was actually used all over the U.S. until the mid-20th century; it was even in Girl Scout handbooks before 1950. There were shiny commercial models as well as homemade ones. It's just a heavily insulated box in which you place a pot heated up on a conventional source; the contents are done and ready to serve six hours later, just by the preserved heat. A slab of soapstone, heated in the woodstove which was presumably in use anyway, was placed in the bottom of some "hayboxes" for even greater efficiency.
As long as the gas is available or the electricity's on, the appliances we are familiar with are ready to use day or night, whatever the weather, so complete convenience trumps severe frugality. But if you lived in a sunny place, were home during the day or out tramping across Algeria, could keep the dog away from the food, and can't or won't pay the utility bill, there is an old, simple technology to make that chili!

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