The Wood Stove Decathlon concluded 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 won first prize with its hybrid stove, which regulates combustion and includes a regulator to ensure efficient heat. Woodstock Soapstone shared its prize with two teams that competed without financial sponsorship, Walker Stoves and IntensiFire. The 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 Dragon Heaters
The smallest box and tower contain the combustion chamber. Wood is fed vertically into the black metal opening in the shortest box. The wood then burns sideways and up the short tower.
The combustion path is highly insulated to facilitate temperatures in excess of 1800F. This ensures that all smoke, creosote, and other volatiles are consumed. You can read more about the combustion system at Dragon Heaters.
Masonry heat capture: at the top of this tower, the hot exhaust is then routed into the primary bell (tallest of the towers) where the hot gases rise. The heat is absorbed by the tower’s 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.
This design approach for heat capture facilitates a very strong draft since there is no friction from flues. It provides for smaller footprint 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.
By using easy and low-cost construction materials masonry-style heaters can now be built for substantially less than traditional masonry heaters.
IntensiFire Wood Stove Insert
“Another stunning innovation came from the IntensiFire firebox insert. Although an untraditional stove entry, this insert was New Zealand inventor Jason Stewart’s way to instantly transform an old, dirty wood stove into a clean-burning model of efficiency. Jasons’ low-cost IntensiFire downdraft device fits inside traditional wood stoves and burns wood up to 60 percent more efficiently.” David Agrell – Popular Mechanics
Masonry Heaters and cookestoves made by Lars Helbro Denmark
A masonry heater is normally heated up with a single fire pr. day. After a fire, that last for about 2 hours,- the heater will provide an ordinary house with a very equal and nice warmth for at least the next 24 hours.
The upper chamber can, after the fire is out,- be used, as a bakeoven for bread, meals etc. and this with a very special and nice impact to your creations.
The efficiency of these stoves are outstanding, compared to the in Denmark more common metal stoves, and boilers.
My stoves have been tested by the most recognized and reputable institute in Europe, The Danish Technological Institute. The results was shortly, that 87% of the burning value of the wood (5,226kwh/kg dry wood minus 0,695kwh/kg water) became heat in the house, and approximately 10% went to the chimney as absolutely necessary draft. In others words – very close to 100% efficiency, and of course,- very clean burning. A masonry heater isn´t just a masonry heater. It can be made in a lot of ways, and should be, because the needs are not the same from person to person. Read more