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 are 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 B. Meigs, one of the judges. “It’s a humble area that doesn’t get enough attention.”