Wood and Coal Stove Advisory

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

The pelletised-fuel burner is beautifully engineered to burn an efficient and super-clean fuel.

High-Tech Stoves

After the first catalytic designs were met with a mixed reception, manufacturers sought to increase wood-stove efficiency and reduce emissions without a combuster . . . through pure design. The resulting "high-tech" stoves feature fireboxes lined with insulating firebrick to burn hotter and cleaner than their conventional predecessors. High-velocity, pre-heated air is drawn in through a hollow smoke shelf or vents at back and sides of the fire to fan the flame at critical secondary-combustion points, burning the smoke—but not as effectively as a combuster. High-techs emit two to three times the particulates and are 5 percent to 10 percent less fuel-efficient than a catalytic.

However, lacking a combuster and its housing, the high-techs are smaller and cheaper. And, as the draft can be opened for full air flow, they are nearly as responsive as their "low-tech" antecedents. Their main drawback is size; to date, high-techs satisfying emission restrictions have small fireboxes and limited heating capacity. And, they aren't cheap. At this writing, our local hardware stores are stocking little two-foot-square welded steel high-techs at a price of $350. Stove designers are working to increase high-techs' heating capacity with more elegantly-engineered oxygen flow, but electric fan-forced-draft may be necessary.

Pellet-Burners

The third new innovation is the palletized burner that in less than a decade is claiming more than a third of annual sales in urban areas of California and the Pacific Northwest. It is also becoming the alternative heat source of choice for many all-electric home owners across the nation. The main advantage of these stoves is also their main disadvantage; they are beautifully engineered to burn an efficient and super-clean fuel—but one which is manufactured so must be purchased.

Though it takes a million-dollar plant, wood of any kind—including manufacturing waste usually sent to a dump or incinerated as well as logging slash and trash timber normally left to rot in the woods— can be ground, dried, and compressed into rabbit-feed size pellets of uniform size and density. The stove is highly automated, feeding in pellets with an electric auger and opening the forced-air draft when a thermostat tells it to. The fuel contains only five percent water to be boiled off, so creosote is non existent and fuel-efficiency approaches 80 percent—better than many oil burners. After start-up, the exhaust really can't be called smoke; after being burned twice and passing through a heat-exchanger, it is cool and clean enough to be fan-forced out through a little three-inch direct-vent pipe. Emissions of about one gram/hr are cleanest of any stove design. The only work needed is to dump fuel into the hopper once a day and clean out the ashtray every week or so.

RSS | Comments | E-mail | Print