mtfallsmikey
Addicted to ArboristSite
That's where the gasifier comes into play...it blast-burns, but you really need a bunch of storage to fully utilize it. Plus good dry wood.
Energy Star Tax Credit,gasifiers & marketing
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That's where the gasifier comes into play...it blast-burns, but you really need a bunch of storage to fully utilize it. Plus good dry wood.
barkeatr
ArboristSite Operative
Kieth,
I guess what im asking is how much heat loss do you think the OWBs have sitting out in 30 below weather...I just checked the depth on my Central Boilers insulation foam at the control panel access area. It is 3/4 of an inch thick. thats not much. What is that R-5? with 175 degree water on one side..I think the foam is deeper in other areas..but still, the circulator, valves..all these things are directly exposed to frigid temps. once more there is no airspace/thermal break between the foam and the water, so the foam looses lots of heat to conductive losses.
I agree with your issues, not the personal ones ,but the OWB ones. OWB suck for efficiency. MY OWB stack looks like a just launched saturn 5 launch vehicle upside down... That is one of my motives in wrapping a greenhouse around the OWB and using a magic heat (or two) to extract heat from the stack. I cant do any of the secondary burn things you mention...and I cant afford a new gasifier OWB.
Yukon should start desinging wood pellet or chip boilers for small commercial buildings...We are architects in upstate NY and are working on several wood boiler gasifier projects for school districts. Seems like they are too big for a smaller commercial building and OWB...well they suck pretty much.
love that new energy bill! we are comin aroudn folkS!
Tim
I guess what im asking is how much heat loss do you think the OWBs have sitting out in 30 below weather...I just checked the depth on my Central Boilers insulation foam at the control panel access area. It is 3/4 of an inch thick. thats not much. What is that R-5? with 175 degree water on one side..I think the foam is deeper in other areas..but still, the circulator, valves..all these things are directly exposed to frigid temps. once more there is no airspace/thermal break between the foam and the water, so the foam looses lots of heat to conductive losses.
I agree with your issues, not the personal ones ,but the OWB ones. OWB suck for efficiency. MY OWB stack looks like a just launched saturn 5 launch vehicle upside down... That is one of my motives in wrapping a greenhouse around the OWB and using a magic heat (or two) to extract heat from the stack. I cant do any of the secondary burn things you mention...and I cant afford a new gasifier OWB.
Yukon should start desinging wood pellet or chip boilers for small commercial buildings...We are architects in upstate NY and are working on several wood boiler gasifier projects for school districts. Seems like they are too big for a smaller commercial building and OWB...well they suck pretty much.
love that new energy bill! we are comin aroudn folkS!
Tim
CrappieKeith
Addicted to ArboristSite
We realize that we can not go after the wood burning market as a whole.
The segment we are after is the whole house furnace slice of the pie.
So many folks even when they call here ask for stoves.
There's a big difference between a stove and a furnace.
We are bringing back the Yukon Bison which was a small UL listed and tested furnace that will be even more affordable.
It appears from all of the posts I've been reading that people buy stoves because they are less expensive then a furnace,but then I'm always running into guys asking how much wood will our furnaces take.
They ask this because their stove does not give them 10-15 hour burn times and to be able to stuff more wood into them ...say's they will get longer burn times.
You see a home has a heat load which is different all over the U.S. depending on how cold it is and what the heat loss of their home is.
So many have bought something that they thought would do the job only now it doesn't.
Hence...how much wood can I put in it?
The questions should be...
What kind of afterburn does it have as their are no real gasifiers on the market although some companies advertise that.
There's not a furnace out there that runs the smoke through a fluid bed filter which then turns the smoke into syngas or wood gas to be burned cleanly.
There are furnaces that run smoke through hot screens(catalytic) or there are some like ours that pre heat the combustion air to around 1000 degrees and then mix it into the smoke which burns off the smoke generating another 30-40% of the available btu's.
Most furnaces I've seen run draft speeds in that .04-.06 inches of water column.
Ours are set to operate at .03 or slower if a good draft can be maintained.
At .04" the flue gas temps will hover in that 400 degree range staying above that 250 degree mark where that gas will condense(creosote).
Anything faster is causing the heat you want in your home to be waisted up the flue.
Operating a furnace with slower draft speeds allows the heat exchange surface area to do what it is supposed to do...exchange heat.
The more heat exchange surface area a furnace has the better it is at getting the heat into your ducting and not letting it go up the flue pipe.
Of coarse the last item a furnace should have is a thermostat to cycle the burn rate.This gives the furnace time to exhange heats as the heat builds a blower comes on satisfing the homes call for heat.
The fan and limit will continue to cycle until the heat dies down which does take some time. Eventually the stat will call for heat , starting the burn cycle all over again.
Having thermal mass(dense firebrick) built into the furnace will also aide in extracting btus from the fire and holding them in the furnace in liew of exiting the furnace prematurely.Bricks also maintain a hot enviroment in the firebox to aide in that afterburn I had mentioned.
A strong firebox can deliver heats during power outages as long as the ducting does not make any downward turns.
Stoves typically are not capable of this feature.
Water furnaces would fall into the same catagory of stoves in that they do not work without power.
Tim....you talked about a lot of heat loss.
I know the state of NY did a survey on efficienties a few years ago in regards to OWB's.
They determined that most of them operate in that 30-50% range.
I'm not sure how they arrived at this since there is no test for furnaces today.
Although the Canadian...CSA is coming out with a test soon which I'm sure the EPA will adopt,but at this time there is no standard by which to test furnace too.
There is for stoves however, which is what the EPA 40-60 rule subpart AAA calls for(B-14 &28A).
We now have this new standard that stoves can be rated using the lower heat value. In this new European method it assumes there is no moisture in the wood. So that caloric value is added into the equation when doing efficiency tests.
This new method actually raises the % by about 10% more then the normal % # that we in the US have always used under the normal firetemp against the flue gas temps.
For example is a oil furnace has a 2000 degree flame and a 400 degree flue gas temp.
That would be 80%....take 400 divided by 2000. Which would be 20% going up the stack and 80% staying in the home.
There is also a CO test to preform to determine the efficiency.
Tim...be very carefull with your heat-a-lators as they may creosote up and start on fire.
The best thing you could do would be to burn smaller fires and hotter fires.
Building big fires that go into smoldering phases is where the loss of eficiency comes into play.
Also very dry wood is so important.
Kiln dried wood can make aprox. 12,000 btu's per lb.
Seasoned wood logs at 20% can make aprox. 8000 btu's per lb.
The reason no stove or furnace burns kiln dried wood is that the fire temps would get so hot that the steels would fatiuge, even in our furnaces.
We call for seasoned wood.We know that the firebox walls never got over 930 degrees when the wood was burned with our barometric draft regulator set to .04" of W.C.
Underwritters Labratories would not have listed our furnaces had they had gotten hotter.
They also do not list furnaces under 80% efficient...residential anyway.
Here's another thing Tim.
When you say how effiecent is that ie....stove/furnace on solid fuel?
There is no single #.
Not if your burn rates cycle...because the fire temp and the flue gas temp fluctuate...so there is no single number.
The hotter the fire is and the lower the flue gas temp will give the highest percentage.
There are also other factors.
What is the moisture level of the solid fuel you are burning?
This number can be all over the board.
Another thing to think about is how well the furnace drafts.
The easier it draft the slower you can run the draft speeds giving your furnace longer burn times or in other words you are givng the furnace time to exchange the heat as it is made.
Which aides in efficiency also.
here's one... take 2 homes of the same size (3000s/f) with all of the same charachteristics...ie..windows ,doors,insulations and so on.
Now add in a furnace.The heat calc will say that you need 100,000 btu furnace lets say.
If you put in a 95,000 in one home and a 135,000 in the other and bothe furnace are built in the same fashion ie....bricks,afterburn,stat,draft reg. and so on only the smaller furnace has a bit smaller firebox with less heat exchange surface are...that's why it's rated as small the smaller furnace will be more efficient.
The reason is because it will be asked for heat more often keeping the firebox hotter and the fire will be hotter.
That bigger furnace will be able to heat that home easier ,faster and it will shut down or cycle down sooner causing more cooler fires.
Nice to chat Tim....peace
The segment we are after is the whole house furnace slice of the pie.
So many folks even when they call here ask for stoves.
There's a big difference between a stove and a furnace.
We are bringing back the Yukon Bison which was a small UL listed and tested furnace that will be even more affordable.
It appears from all of the posts I've been reading that people buy stoves because they are less expensive then a furnace,but then I'm always running into guys asking how much wood will our furnaces take.
They ask this because their stove does not give them 10-15 hour burn times and to be able to stuff more wood into them ...say's they will get longer burn times.
You see a home has a heat load which is different all over the U.S. depending on how cold it is and what the heat loss of their home is.
So many have bought something that they thought would do the job only now it doesn't.
Hence...how much wood can I put in it?
The questions should be...
What kind of afterburn does it have as their are no real gasifiers on the market although some companies advertise that.
There's not a furnace out there that runs the smoke through a fluid bed filter which then turns the smoke into syngas or wood gas to be burned cleanly.
There are furnaces that run smoke through hot screens(catalytic) or there are some like ours that pre heat the combustion air to around 1000 degrees and then mix it into the smoke which burns off the smoke generating another 30-40% of the available btu's.
Most furnaces I've seen run draft speeds in that .04-.06 inches of water column.
Ours are set to operate at .03 or slower if a good draft can be maintained.
At .04" the flue gas temps will hover in that 400 degree range staying above that 250 degree mark where that gas will condense(creosote).
Anything faster is causing the heat you want in your home to be waisted up the flue.
Operating a furnace with slower draft speeds allows the heat exchange surface area to do what it is supposed to do...exchange heat.
The more heat exchange surface area a furnace has the better it is at getting the heat into your ducting and not letting it go up the flue pipe.
Of coarse the last item a furnace should have is a thermostat to cycle the burn rate.This gives the furnace time to exhange heats as the heat builds a blower comes on satisfing the homes call for heat.
The fan and limit will continue to cycle until the heat dies down which does take some time. Eventually the stat will call for heat , starting the burn cycle all over again.
Having thermal mass(dense firebrick) built into the furnace will also aide in extracting btus from the fire and holding them in the furnace in liew of exiting the furnace prematurely.Bricks also maintain a hot enviroment in the firebox to aide in that afterburn I had mentioned.
A strong firebox can deliver heats during power outages as long as the ducting does not make any downward turns.
Stoves typically are not capable of this feature.
Water furnaces would fall into the same catagory of stoves in that they do not work without power.
Tim....you talked about a lot of heat loss.
I know the state of NY did a survey on efficienties a few years ago in regards to OWB's.
They determined that most of them operate in that 30-50% range.
I'm not sure how they arrived at this since there is no test for furnaces today.
Although the Canadian...CSA is coming out with a test soon which I'm sure the EPA will adopt,but at this time there is no standard by which to test furnace too.
There is for stoves however, which is what the EPA 40-60 rule subpart AAA calls for(B-14 &28A).
We now have this new standard that stoves can be rated using the lower heat value. In this new European method it assumes there is no moisture in the wood. So that caloric value is added into the equation when doing efficiency tests.
This new method actually raises the % by about 10% more then the normal % # that we in the US have always used under the normal firetemp against the flue gas temps.
For example is a oil furnace has a 2000 degree flame and a 400 degree flue gas temp.
That would be 80%....take 400 divided by 2000. Which would be 20% going up the stack and 80% staying in the home.
There is also a CO test to preform to determine the efficiency.
Tim...be very carefull with your heat-a-lators as they may creosote up and start on fire.
The best thing you could do would be to burn smaller fires and hotter fires.
Building big fires that go into smoldering phases is where the loss of eficiency comes into play.
Also very dry wood is so important.
Kiln dried wood can make aprox. 12,000 btu's per lb.
Seasoned wood logs at 20% can make aprox. 8000 btu's per lb.
The reason no stove or furnace burns kiln dried wood is that the fire temps would get so hot that the steels would fatiuge, even in our furnaces.
We call for seasoned wood.We know that the firebox walls never got over 930 degrees when the wood was burned with our barometric draft regulator set to .04" of W.C.
Underwritters Labratories would not have listed our furnaces had they had gotten hotter.
They also do not list furnaces under 80% efficient...residential anyway.
Here's another thing Tim.
When you say how effiecent is that ie....stove/furnace on solid fuel?
There is no single #.
Not if your burn rates cycle...because the fire temp and the flue gas temp fluctuate...so there is no single number.
The hotter the fire is and the lower the flue gas temp will give the highest percentage.
There are also other factors.
What is the moisture level of the solid fuel you are burning?
This number can be all over the board.
Another thing to think about is how well the furnace drafts.
The easier it draft the slower you can run the draft speeds giving your furnace longer burn times or in other words you are givng the furnace time to exchange the heat as it is made.
Which aides in efficiency also.
here's one... take 2 homes of the same size (3000s/f) with all of the same charachteristics...ie..windows ,doors,insulations and so on.
Now add in a furnace.The heat calc will say that you need 100,000 btu furnace lets say.
If you put in a 95,000 in one home and a 135,000 in the other and bothe furnace are built in the same fashion ie....bricks,afterburn,stat,draft reg. and so on only the smaller furnace has a bit smaller firebox with less heat exchange surface are...that's why it's rated as small the smaller furnace will be more efficient.
The reason is because it will be asked for heat more often keeping the firebox hotter and the fire will be hotter.
That bigger furnace will be able to heat that home easier ,faster and it will shut down or cycle down sooner causing more cooler fires.
Nice to chat Tim....peace
Last edited:
Highbeam
ArboristSite Guru
"It appears from all of the posts I've been reading that people buy stoves because they are less expensive then a furnace"
Ugh. Let me be the first to say that I own a woodstove for many reasons and none of them are because they are less expensive than a furnace. I don't care if the furnace was 10$. I can't watch the fire, warm my hands by it, or be warmed by its radiant heat.
The only reason I would want a furnace is that I can theoretically get a more even heat with it but then I would need power to run it and ductwork to move that heat.
Ugh. Let me be the first to say that I own a woodstove for many reasons and none of them are because they are less expensive than a furnace. I don't care if the furnace was 10$. I can't watch the fire, warm my hands by it, or be warmed by its radiant heat.
The only reason I would want a furnace is that I can theoretically get a more even heat with it but then I would need power to run it and ductwork to move that heat.
whitemountain
ArboristSite Operative
After reading all these posts I am very clear on one thing. People are passionate about their wood-burning appliances. I for one am glad. I wouldn't trade mine for a seasons worth of pro-pain. And isn't what these forums are all about, expressing opinions, expressing experiences and learning.
Another thing I've learned is that I don't know squat about the physics or chemistry involved in combustion. I for one am glad I can focus on harvesting wood and not worry about my wood-burner. It is clean-burning, efficient, and I love it. That's all I really need to know.
I am also glad that technology in these areas continues to improve. Maybe in 20 or so years when I am ready to replace my current heating appliance I can get one that will generate it's own electricity! Seriously though, as technology continues to advance better and better things come down the pike.
Another thing I've learned is that I don't know squat about the physics or chemistry involved in combustion. I for one am glad I can focus on harvesting wood and not worry about my wood-burner. It is clean-burning, efficient, and I love it. That's all I really need to know.
I am also glad that technology in these areas continues to improve. Maybe in 20 or so years when I am ready to replace my current heating appliance I can get one that will generate it's own electricity! Seriously though, as technology continues to advance better and better things come down the pike.
CrappieKeith
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CrappieKeith
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