Stoves/Furnaces

General

Pellet stoves are commonly made to burn only wood pellets. However, multi-fuel pellet stoves are capable of burning a lot of different biomass fuels such as corn and other biomass pellets. Pellet stoves dispense pellets from a hopper into a fire pot or burn box which is visible through a glass window. A typical hopper holds from 40 pounds (18 kg) to over 100 pounds (45 kg) of pellets (“Pellet Stoves: How they Work”). An auger or large screw, driven by an electric motor, deposits the pellets at a steady rate into the fire (“Pellet Stoves: How they Work”). A fan blows a jet of air across the fire maintaining a high temperature and enabling the pellets to burn evenly and efficiently (“Pellet Stoves: How they Work”). A second fan blows hot air, warmed by passage through heat exchanger pipes that run through the interior of the stove, into the surrounding room (“Pellet Stoves: How they Work”). Exhaust is vented through a pipe that is smaller and less expensive to install than an ordinary chimney (“Pellet Stoves: How they Work”).

pellet_stove_cutaway.gif (From “Pellet Stoves: How they Work”)

Most pellet stoves are free-standing and supported by legs or a pedestal. Designed for almost any living area (restrictions may apply to sleeping areas), they have built-in heat shields that allow them to be situated very near to a wall (“Pellet Stove”). One restriction is that they need to stand on non-combustible floor covering such as tile (“Pellet Stove”).

Top feed vs. Bottom feed

Top feed stoves send pellets down onto the fire and bottom feeders store the pellets behind or beside the fire. Bottom feeders have the edge with standard grade pellets because the feeding action moves ash and clinkers away from the burn area (“Pellet Stove”). This keeps air inlets open and lengthens the time between cleanings of the burn box. In some top feed designs, grates or rotating burn pots can also shift spent fuel from the inlets preventing clogs that result in lower efficiency (“Choosing and Buying a Pellet Stove”). Top feed stoves have an advantage in heating efficiency since pellets stay in the burn box until they are completely burned (“Choosing and Buying a Pellet Stove”).

Pros:

Pellet stoves are more efficient (better for you budget), cleaner burning (better for air quality and less ash clean up), and easier to use than conventional wood burning appliances like a fireplace or wood stove.

Some pellets are made from waste materials created from the manufacture of wood products (i.e. furniture and lumber), material that is useless otherwise (“Pellet Stove Pros and Cons”).

Unlike wood stoves, pellet stoves work by convective heat so they don’t get too hot to touch which is an important consideration for families with children (“Pellet Stove”).

Pellet stove inserts are available to convert an existing fireplace.

On a larger scale, pellet furnaces are large units designed to heat an entire house using a system of duct work. They are usually installed in a basement or other non-living area of the house (“Pellet Stove”).

Pellet stoves are convenient. The fire starts with the push of a button or by adjusting a thermostat. Modern pellet stoves have a thermostat that allows precise control of room temperature by adjusting the rate at which fuel is added. The thermostat may be programmable so that, for example, at night the stove automatically runs at its lowest feed rate (“Pellet Stove Pros and Cons”).

Pellets require less storage space and are easier to handle than wood.

Pellets are typically packaged in 40 lb bags which can be easily stacked and transported (“Pellet Stove Pros and Cons”).

Pellet stoves typically range in price from $1700 to $3300. Installation costs are low, typically between $350 and $550 (“Pellet Stove Cost”).

Burning pellets produces in-cycle CO2 where as gas or coal stoves pollute with out of cycle CO2.

Cons:

Pellet stoves are mechanical and therefore more prone to malfunction than a wood or gas stove, especially if they are not maintained correctly (“Pellet Stove Pros and Cons”).

Wood stoves are inefficient and polluting, but they don’t have many moving parts that need cleaning and that can malfunction like pellet stoves do (“Pellet Stove”).

Pellet stoves require electricity to run the various fans and motors. This adds to the operating cost and if the power goes out the stove cannot run.

Pellet stoves can make a noise: “a constant, dull, mechanical rumble” (“Pellet Stove Pros and Cons”).

Pellet stove fires are not as visually pleasing as wood stoves or gas stoves. The fire is small and concentrated.

Pellet stoves need maintenance to ensure efficiency. They need weekly and monthly maintenance by the owner as well as having the stove cleaned by a professional yearly.

For more information explore the following websites and articles:
http://www.daviddarling.info/encyclopedia/P/AE_pellet_stove.html
http://www.daviddarling.info/encyclopedia/P/AE_pellet_stove_manufacturers_United_States_and_Canada.html
http://www.oldhouseweb.com/how-to-advice/how-to-choose-a-pellet-stove.shtml
http://www.smartmoney.com/spending/deals/should-you-buy-a-pellet-stove-18323/

Works Cited:

“Choosing and Buying a Pellet Stove.” Encyclopedia of Alternative Energy and Sustainable Living Accessed November 17, 2009. http://www.daviddarling.info/encyclopedia/P/AE_pellet_stove_buying.html

“Pellet Stove.” Encyclopedia of Alternative Energy and Sustainable Living Accessed November 17, 2009. http://www.daviddarling.info/encyclopedia/P/AE_pellet_stove.html

“Pellet Stove Cost.” Encyclopedia of Alternative Energy and Sustainable Living Accessed November 17, 2009. http://www.daviddarling.info/encyclopedia/P/AE_pellet_stove_cost.html

“Pellet Stove: How they Work.” Encyclopedia of Alternative Energy and Sustainable Living Accessed November 17, 2009. http://www.daviddarling.info/encyclopedia/P/AE_pellet_stoves_how_they_work.html

“Pellet Stove Pros and Cons.” Encyclopedia of Alternative Energy and Sustainable Living Accessed November 17, 2009. http://www.daviddarling.info/encyclopedia/P/AE_pellet_stove_pros_and_cons.html