Wood Combustion

1
Wood Combustion

• Not used as much in the past.
• Low cost / Low efficiency.
• Poses some environmental concerns including
  erosion and flooding form wood gathering, and the
  emission of carcinogens.

2
The Wood Cumbustion cycle-3 components
nessicary wood (fuel), air, and
high
tempretures

1. Moisture evaporates from the wood. So fresh or
   green wood does not make an efficient fuel.
2. Wood catches fire at 315 degrees Celsius.
   
3. The burn wood decomposes to charcoal and smoke.
   This material will combust at tempretures
   approaching 600 degrees. A duel combustion stove
   is required to do this.

3
Stove Design and Efficiency

• In a standard fire place only the fist stage of
  wood combustion takes place and much of the
  chemichal energy in the wood goes out the
  chimney.
  
• Tradtional fireplaces also pull in cold air from
  outside to replenish the air being consumed in
  the fire. Because of this some fire places have
  negative efficiencies.
• To increase efficiency you can reduce the air
  intake by adding a glass screen in front of the
  fire. Or you can arrange the logs in way so that
  they burn more rapidly.

4
Dual Burning Stoves-By sending the smoke
through a second combustion area we can extract
more BTU's per unit weight of wood.
5
Cooking stoves in Developing Countries

• This 3 stone stove is used for cooking in many
  develpoping countries.
• Wood is fed into the fire and used to heat the
  pot for cooking.