- Nov 27, 2012
- 0
Question:
The basics of wood burning are explained in many places, how to start a fire, burn it clean and so forth. But I could not find anything on the web on how to extract the most heat from a load. We have a Quadrafire 3100 which is a modern non-cat. Lots of wood goes through it but it's often tough to squeeze enough room heat out of it. You can't run this stove at full bore for long, because it can overheat and also it would devour a whole forest in no time. Could be too much draft, who knows. Wood got very expensive now so it's important to use it effectively. Is there any description on the web that describes the more intricate things about wood heating, beyond the basics?
Answer:
You raise a very good question. How to extract the most heat from a load? I believe this is difficult to answer in our current environment, where combustion efficiency is paramount and heat transfer-efficiency is secondary. The modern non-cat stove is purposely designed to keep enough heat inside the stove to completely burn the gases and soot while still inside the stove. Insulators are used to accomplish this and this naturally means less heat is conducting through the stove walls and into your room. If the materials used are good and the design is good you'll get the best the stove can offer in overall efficiency (that is, the proper balance of combustion and heat-transfer efficiency). The overall effect is generally good and preferred to some of the older methods which concentrated more on heat-transfer efficiencies and sacrificed combustion efficiency.I find that I prefer the catalytic model. A well designed catalytic model will burn efficiently and allow for a more direct conduction of heat from the primary burn chamber while the smoke still burns off, but at a lower ignition temperature than required by a non-cat design. The catalyst allows the gasses and soot to start burning off (the secondary burn) while only in the range of 550-650 degrees, instead of the usual requirement of 1300 degrees needed in a non-cat setup. That allows for more extraction of heat while not compromising overall combustion efficiency.These are the basics as I understand them. However, I am not an engineer and I do not have a background in stove design. I'm speaking from general experience and not as a scientist. Several years ago Jay Shelton wrote some books about the burning of solid fuels and discussed heat-transfer and combustion efficiencies. He took a very scientific approach. This was before the "new" technology stoves started appearing. I am curious what he would say about the new models and how non-cat compares with catalytic. If you can find his books at your library they are worth the effort to read.
Sean
The basics of wood burning are explained in many places, how to start a fire, burn it clean and so forth. But I could not find anything on the web on how to extract the most heat from a load. We have a Quadrafire 3100 which is a modern non-cat. Lots of wood goes through it but it's often tough to squeeze enough room heat out of it. You can't run this stove at full bore for long, because it can overheat and also it would devour a whole forest in no time. Could be too much draft, who knows. Wood got very expensive now so it's important to use it effectively. Is there any description on the web that describes the more intricate things about wood heating, beyond the basics?
Answer:
You raise a very good question. How to extract the most heat from a load? I believe this is difficult to answer in our current environment, where combustion efficiency is paramount and heat transfer-efficiency is secondary. The modern non-cat stove is purposely designed to keep enough heat inside the stove to completely burn the gases and soot while still inside the stove. Insulators are used to accomplish this and this naturally means less heat is conducting through the stove walls and into your room. If the materials used are good and the design is good you'll get the best the stove can offer in overall efficiency (that is, the proper balance of combustion and heat-transfer efficiency). The overall effect is generally good and preferred to some of the older methods which concentrated more on heat-transfer efficiencies and sacrificed combustion efficiency.I find that I prefer the catalytic model. A well designed catalytic model will burn efficiently and allow for a more direct conduction of heat from the primary burn chamber while the smoke still burns off, but at a lower ignition temperature than required by a non-cat design. The catalyst allows the gasses and soot to start burning off (the secondary burn) while only in the range of 550-650 degrees, instead of the usual requirement of 1300 degrees needed in a non-cat setup. That allows for more extraction of heat while not compromising overall combustion efficiency.These are the basics as I understand them. However, I am not an engineer and I do not have a background in stove design. I'm speaking from general experience and not as a scientist. Several years ago Jay Shelton wrote some books about the burning of solid fuels and discussed heat-transfer and combustion efficiencies. He took a very scientific approach. This was before the "new" technology stoves started appearing. I am curious what he would say about the new models and how non-cat compares with catalytic. If you can find his books at your library they are worth the effort to read.
Sean
