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Warming up to solar ovens

by Sue Halpern and Bill McKibben

This article appeared in the May 2007 issue of House & Garden

image: Tulsi Hybrid solar oven


They haven't reached the mainstream yet, but solar cookers are attracting attention for producing intensely flavored food without match or plug.

Don't get us wrong—we have nothing against our 36-inch wall oven. It has browned countless loaves of whole wheat and roasted a decade's worth of Thanksgiving turkeys. It is so stalwart that most of the time we pay it no mind. It costs money to operate, sure, but how much, exactly, or how much power it draws, we couldn't say. And until we were handed a steaming hot cup of tea in Tibet by a man who lived about as far off the grid as it is humanly possible to get, it didn't occur to us that it might be possible to bake a baguette or fricassee a chicken without turning on our oven in the first place.

The cup of tea had been made from water heated by the sun with the help of what looked like an inverted umbrella of reflectors—what is known as a parabolic solar cooker. It was a simple design, less sophisticated even than the first solar cooker, designed by the Swiss naturalist Horace de Saussure in 1767. Almost three centuries after de Saussure, our homes are chock-full of expensive convection ovens, gas broilers, microwaves, and infrareds. What most of us don't have is a way of cooking minus match or socket.

But what if there is a storm and you are without power? What if there is a heat wave and you don't want to be within ten feet of your oven? (Yes, you can grill, but has anyone invented a way to grill your 7-year-old's birthday cake?) Or what if you're on a canoe trip and have a sudden hankering for Parker House rolls? All of these are possible if you cook with the sun.

Technology typically trickles down the economic ladder, starting with the people who can afford the next new thing, but in the case of solar cookers, a technology so basic that it sets the low bar for low-tech, it has been trickling up. In the past few years a number of nonprofit organizations and forprofit companies have been importing and refining, for the American market, solar cookers originally designed for the developing world— for villages without electricity, for refugee camps, for places where the forests have been decimated for fuel.

"Solar cooking is getting to be more mainstream," says Paul Munsen, president of Sun Ovens International, a company that last year sold about 4,000 solar cookers in the United States, making it one of the bigger solar oven companies in the country. "We're selling to people who want to bake in the summer without raising the temperature in their kitchen, which they'll then have to cool down with air-conditioning. We're selling to the people who like the naturalness of this kind of cooking. We're selling to the people who are into the slow-food movement—solar cookers can take an hour or two longer than you're used to—and to the people who are trying to live a green lifestyle."

Munsen's Sun Oven is a sturdy, deceptively simple-looking insulated plastic box topped by an accordion of reflectors. When the reflectors are unfolded, they ring the box's glass door. We put our oven out on our deck in the middle of December, and within about an hour the thermometer inched up to 200 degrees. Not good enough to boil water, but we weren't boiling water, we were letting a chicken stew in its own juices, which it did, eventually. Because solar cooking typically requires no additional water, the flavor was intense and fresh.

"I love to cook, and when I first tried cooking in a solar oven, I found that the tastes coming out of it were extraordinary," says Bill Potts, a volunteer at the Solar Oven Society, a Minneapolis-based group that sells a solar box cooker in the United States called the Sport, which is similar in design to the Sun Oven. (U.S. sales are used to offset the cost of distributing the Sport to individuals in Haiti, Africa, and other parts of the third world. Munsen's company, though not a nonprofit, works closely with the Rotary Club and other nonprofits to get the ovens in the hands of people in the developing world, while another organization, Solar Household Energy, is dedicated to supplying the HotPot, a low-cost panel cooker it designed, to people in Latin America and West Africa.) Potts maintains an online file of recipes, such as Japanese chicken kebabs and corn on the cob, that he has adapted for the solar oven. "I make potato-leek soup in the solar cooker," he said. "It's got so much flavor it's like you're inside the leek."

Potts's adaptations have a lot to do with how to orient the cooker to the sun, which brings up the main problem with these devices: clouds. Clouds can put a damper on the whole solar enterprise. This is less of a problem in, say, Nevada, where Paul Munsen recently sold a Sun Oven to a doctor who puts his dinner out to cook when he leaves for work in the morning and finds it waiting when he returns after dark, than it is in Michigan or Vermont or New Jersey, except in summer. "About twenty years ago I saw an ad at the back of one of my wife's magazines that said, ?Send in three dollars and we'll send you plans for building a solar oven,' " recalls David Chalker, who lives in intermittently sunny upstate New York. "My wife thought I was crazy, but when I put a steaming hot chicken, with carrots and potatoes, on the table, she changed her mind.

"The Achilles' heel," Chalker continued, was the sun. It couldn't be trusted, not in upstate New York. A few years ago, trolling the Internet, Chalker came across a company in India that was making a portable hybrid solar oven that looked like a Samsonite suitcase. Much like a hybrid car, which augments its battery with conventional gasoline, the hybrid solar oven has the capacity to supplement the sun's rays with a super-efficient electric heating element if the temperature dips below 300 degrees. For Chalker, finding a hybrid solar oven was a revelation that set him on what he calls his "path." He left his job as the supervisor at a pump manufacturer, traveled to India, helped the Indian inventor rejigger the cooker for American consumers, and is now the sole distributor of the Tulsi-Hybrid on this side of the Atlantic. A solar oven that can be plugged in may not satisfy the purists, and it probably won't solve world hunger, but Chalker believes that because it is essentially fail-proof, the Tulsi-Hybrid has a real chance to heat up the solar cooking market in the United States.

"This is a monumental step in solar cooking," he says with the zeal of a guy on a path. "The fact is, once you take the lid off a pot that has been cooked in the sun, you start to look at the world differently."

Related pages:
Tulsi-Hybrid solar cooker
Sun Ovens
Energy-efficient appliances

This article appeared in the May 2007 issue of House & Garden


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