WASHINGTON

Only blocks away, the Energy Department manages the search for quarks and NASA scours the heavens for Earth-like planets. But inside a big white tent on the National Mall, the focus is on something simpler: oak, ash and elm, and how to make them heat a house with as little pollution as possible.

It is not rocket science, but the 12 teams that were competing to solve the problem are finding ways to get twice as much heat out of a log of firewood. The effort preserves woodlands, reduces the labor and expense for the mostly low-income people who use wood, and cleans the air.

The stoves on display here, in a tent with a dozen chimneys incongruously poking through the roof, use combinations of computer controls, catalytic converters and sophisticated gas-flow modeling.

“It’s a combination of low tech and high tech,” said James Meigs, one of the judges. “It’s a humble area that doesn’t get enough attention.”

Late last Tuesday, the judges announced a winner, based on efficiency, cleanliness, consumer appeal and price: an entry by Woodstock Soapstone, of Woodstock, Vt., which builds stoves that are not only clean and efficient, but are intended to be eye-catching, too. The company was awarded $25,000, but the bragging rights are probably worth more, said John Ackerly, president of the Alliance for Green Heat, which is running the competition sponsored by the New York State Energy Research and Development Authority, the federal Departments of Energy and Agriculture, Popular Mechanics magazine and others.

Ackerly, citing census data, said wood was the primary source of heat for about 2.3 million American households, largely in rural areas.

Wood stoves typically deliver only 40 to 50 percent of the energy potential of the wood in the space they are supposed to heat. Some of the models in the competition deliver more than 90 percent and make the smoke cleaner. In wood stoves, cleanliness and efficiency turn out to be the same thing.

The stoves are mostly cast iron or steel, and some are covered in enamel or soapstone. They look like lowtech devices, but in the tent they have been hooked up to digital meters that count their output of carbon monoxide and fine particles, which, like the particles from coal plants, cause respiratory problems. In places with many stove-equipped houses and unfavorable topography, the particles can build up to high concentrations.

Many of the stoves use catalytic converters, somewhat like the ones in cars, to take carbon monoxide and hydrocarbons, both pollutants, and convert them at high temperature into simple combustion products: carbon dioxide and water.

¦ ACCORDING TO census data, wood was the primary source of heat for about 2.3 million American households, largely in rural areas.
¦ WOOD STOVES typically deliver only 40 to 50 percent of the energy potential of the wood in the space they
are supposed to heat.