Wöhler Brings New Particulate Analyzer to Wood Stove Design Challenge

The German precision test equipment manufacturer, Wöhler, is providing one of its new Wöhler SM 500 particulate analyzers to do accurate PM 2.5 testing in the field. The Wöhler unit is a Suspended Particulate Analyzer for online PM 2.5 mass concentration measurements of small solid fuel appliances. The brand new technology just came out last year to meet requirements under a new German law that requires wood stoves and boilers to be checked in the field for emissions every year. German chimney sweeps play the same role as vehicle emission testing stations in the US. If the emissions are too high, the problem has to be fixed or the system taken out of service.


The Wood Stove Design Challenge will be using the Wöhler equipment at its national exhibition to educate policy makers and the public about modern wood heater emissions. The 10 judges who are preparing for the Challenge are gaining experience in using the new Wöhler technology in anticipation of using on-site testing of emissions. The Wöhler SM 500 is now at the Brookhaven National Laboratory where one of the judges, Dr. Thomas Butcher, is performing trial testing. Other judges will join him in coming months as they test the fueling protocol and compare the Wöhler SM 500 to the traditional, but more cumbersome, dilution tunnel test procedure that is used in wood stoves tests to ensure they meet EPA emissions standards. Dilution tunnels are large, time-consuming and expensive to use and are not an option for testing up to 14 wood stoves on the National Mall over a 5-day period.

In Race to Build Cleaner Wood Stove, 16th and 21st Centuries Collide

 Alliance for Green Heat, January 16, 2013 - A wood stove design competition to be held on the National Mall in DC this November is pitting 16th century designs against microchip-controlled automation. And it is not clear who will win.

“The wood stove has become of icon of tradition,” said John Ackerly, President of the Alliance for Green Heat. “But the question is, can microprocessors deliver far cleaner and more efficient wood heat at a very affordable price?”

For most Americans, clean renewable energy conjures up images of solar panels and wind turbines – not wood stoves and furnaces. But that could change. “This competition may produce technology so consistently clean that wood can become a top tier renewable like solar,” Ackerly said, whose organization is hosting the competition.

Eight of the 32 entries are innovations on masonry heaters, a technology developed in the 16th century when wood prices soared in Europe. These heaters are known for their ability to efficiently store and radiate heat for hours after the initial fire goes out. However, they tend to be expensive and may lose points in the affordability category.

Five of the stoves are automated, using oxygen sensors and thermostats to control some or all of the combustion. Some make their own electricity while others require it to operate their automatic controls. Some can recharge cell phones and be operated by smart phones.

Three of the stoves are technically boilers which send water to heat other rooms in the house, but look like regular living room wood stoves. Seven of the stoves are downdraft designs, meaning the flames are sucked down during the combustion process, which can result in extremely low emissions. Other designs don’t easily fit into any single category because they include several innovative features or are just very unique. Eight of the stoves are already in stores, vying for recognition and market share.

With a few exceptions, most teams come from North America and Europe, where the race to deploy renewable energy heating equipment is building momentum. Later this month, nine judges representing universities, institutions and government agencies will narrow down the 32 entries into 12-16 finalists that will be rigorously tested by trained stove technicians until an overall winner is chosen. Funding for the competition comes from government agencies, foundations and sponsors.

“The history of wood heating is not always a linear progression towards cleaner and more efficient designs,” said Ackerly, who created the competition with college friend Jim Meigs, now Editor-in-Chief of Popular Mechanics. “The pellet stove, invented in the U.S. in 1973, was a great leap in the history of cleaner wood heating. A similar leap is needed with cord wood, and when the right technology meets the right price, we could see a renaissance in wood heating,” Ackerly said.

To learn more about the Wood Stove Design Challenge, visit: http://www.forgreenheat.org/stovedesign.html