The Wood Stove Decathlon concluded Tuesday (Nov 19,2013) after five days of testing and judging among teams that came from around the world. The goal? “Heat more cleanly, cheaply, and renewably,” said John Ackerly, organizer and president of the Alliance for Green Heat. The New Hampshire company Woodstock Soapstone snared the $25,000 first prize with its hybrid stove, which regulates combustion and includes a regulator to ensure efficient heat. It also comes with unique plates that can be personalized to a homeowner’s taste. Beyond the heating element, the decathlon had a warm air of collaboration and congeniality. Woodstock Soapstone shared its prize with the two teams that competed without financial sponsorship, Walker Stoves and IntensiFire. The $10,000 second prize was shared by Wittus-Fire by Design and Travis Industries, which donated its share of the prize back to the Alliance for Green Heat. Winners for individual categories were HWAM for innovation; Travis Industries for lowest carbon monoxide emissions and also for market appeal; IntensiFire for affordability; the University of Maryland’s Mulciber for lowest particulate emissions; and Woodstock Soapstone for efficiency.
Rocket Heater Combustion System by Dragonheaters.com
The smallest box and tower containes the combustion chamber. Wood is fed vertically into the black metal opening in the shortest box. The wood then burns sideways and then up the short tower. The combustion path is highlyinsulated to facilitate temperatures in excess of 1800F. This insures that all smoke, creosote and other volatiles are consumed. You can read more about the combustion system here…
Masonry Heat Capture. At the top of this tower, the supper hot exhaust is then routed into the primary bell (tallest of the towers) where the hot gases rise. The heat is absorbed by the towers masonry and the exhaust gases cool, become heavier, and thus sink and exit at the bottom. Depending on the design the exhaust can enter another smaller bell (tower) where the same process happens again, or in the case of a single bell, the exhaust exits to the chimney.
Advantages of Bells
This design approach for heat capture facilitates a very strong draft, since there is no friction from flues. It provides for smaller foot print designs since the heat capture is vertical rather than horizontal and it is inherently more efficient than flues, meaning you need less mass to capture the same number of BTUs. You can read more about why bells are more effective here.
By using easy and low cost construction materials masonry style heaters can now be built for substantially less than traditional masonry heaters.