Solar Cooking in a Cardboard Box

Jon Bohmer with the Kyoto Box Solar Oven

Inventor turns cardboard boxes into eco-friendly solar powered oven

When Jon Bohmer sat down with his two daughters to create a simple project they could work on together, he didn’t realize they’d hit upon a solution to one of the world’s biggest problems for just $5: A solar-powered oven.

The ingeniously simple design uses two cardboard boxes, one inside the other, and an acrylic cover that lets in the sun’s rays and traps them. 

Black paint on the inner box, and silver foil on the outer one, help concentrate the heat.  The trapped rays make the inside hot enough to cook casseroles, bake bread and boil water.

What the box also does is eliminate the need in developing countries for rural residents to cut down trees for firewood. About 3 billion people around the world do so, adding to deforestation and, in turn, global warming.

By allowing users to boil water, the simple device could also potentially save the millions of children who die from drinking unclean water.

Bohmer’s invention won the FT Climate Change Challenge, which sought to find and publicize the most innovative and practical solution to climate change.

“A lot of scientists are working on ways to send people to Mars.  I was looking for something a little more grassroots, a little simpler,” Bohmer said.

Bohmer’s contest win notwithstanding, solar cooking with a cardboard oven isn’t new.  Two American women, Barbara Kerr and Sherry Cole, were the solar box cooker’s first serious promoters in the 1970s.  They and others joined forces to create the non-profit Solar Cookers International — originally called Solar Box Cookers International — in 1987.

Further, the organization’s executive director, Patrick Widner, said that the plans for a solar box cooker were found in a book published by the Peace Corps in the 1960s.

“We are pleased that Mr. Bohmer has taken up the cause and interest of the 95 member organizations and 160 individuals of the Solar Cookers Worldwide Network,” Widner said.  ”It would be a pleasure to work with Mr. Bohmer in Kenya where we have been promoting the use of solar cookers for ten years.”

Bohmer, a Norwegian-born entrepreneur based in Kenya, said he also had been looking at solutions “way too complex, for way too long.”

“This took me about a weekend, and it worked on the first try,” Bohmer said. “It’s mind-boggling how simple it is.”

The contest was organized by the Forum for the Future — a sustainable development charity — and the Financial Times newspaper.

Bohmer’s invention beat about 300 other entries, including a machine that turns wood and other organic material into charcoal, wheel covers that make trucks more fuel efficient by reducing drag, and a feed supplement for livestock that reduces the methane they emit by 15 percent.

Bohmer named his invention the Kyoto Box, after the international environmental treaty to reduce global warming.

The box can be produced in existing cardboard factories. It has gone into production in a factory in Nairobi, Kenya, that can churn out about 2.5 million boxes a month.

Bohmer has also designed a more durable version, made from recycled plastic, which can be produced just as cheaply.

He envisions such cardboard ovens being distributed throughout rural Africa.

“In the West, we cook with electricity, so it’s easy to ignore this problem,” he said.  ”But half the world’s population is still living in a stone age.  The only way for them to cook is to make a fire.

“I don’t want to see another 80-year-old woman carrying 20 kilos of firewood on her back.  Maybe we don’t have to.”

Source: CNN/ EcoSolutions

The design of the Kyoto Box Solar Oven, while simple, does have a number of shortcomings:

Kyoto Box Solar Oven

The reflectors will not stay in position with even the slightest wind.

When the sun is not straight overhead, in order to make use of the reflectors, the entire box has to be tipped up to face the sun. This causes the cooking pot to slide around and spill food.

Rather than have four reflectors, it is much more desirable to have a single rear reflector like the The “Minimum” Solar Box Cooker pictured below.

The "Minimum" Solar Box Cooker uses a single back reflector that is very easily tilted up and down to track the sun instead of tilting the entire cooker as is the case with the Kyoto Box.

The “Minimum” Solar Box Cooker is a simple box cooker that can be built in a few hours for very little money. This is a full-power cooker that works very well, and is in no way minimum as far as its cooking power goes.

Many solar cooker designs are portable which allows for solar cooking anywhere that the sun shines.  So whether you build a solar cooker yourself or purchase a light weight solar oven that is ready to use, you will enjoy the benefits of clean non-polluting solar cooking with solar energy direct from the sun.

Do you use a Solar Cooker?

Share your experience with others and help spread the word about natural sun powered solar cooking by leaving a comment below.

Thanks,
-Red

-

I really appreciate that you keep coming back to my site, it's loyal people like you that make what I do worth it. If you have any questions feel free to email me. Oh and since you obviously like our site it'd be great if you could share it with a friend... They'll love you for it!

Tagged as: renewable energy, Solar Cooking, Solar Energy, solar oven, sustainable technologies