Long Burn vs Efficiently

[firebrick43]

Whitespider

Ok, you are relating everything to "your" current setup in the basement.

If I am in the house I am there to baby sit it as it 3 feet away from the couch. If I am not in the house my house my fire goes out. My house has been upgraded to mitigate the lack of a constant fire. Upgrading the building envelope pays back all year just not in the winter.

I suppose by your post you have an unfinished basement. How about insulating the walls with 2" extruded polystyrene "Dow blue board". This made a hude difference in the comfort of my house. The place some black painted drums full of water around your stove. Run the stove full and let the radiated heat go into the water so it real eases when you go to work.

 

[Whitespider]

Ok, you are relating everything to "your" current setup in the basement.

No I'm not... I simply asked you a question about your setup, and how you said you run it.

I suppose by your post you have an unfinished basement. How about insulating the walls with 2" extruded polystyrene "Dow blue board". This made a hude difference in the comfort of my house. The place some black painted drums full of water around your stove. Run the stove full and let the radiated heat go into the water so it real eases when you go to work.

Say what?? I'm not trying to heat the basement‼ I'm heating the living space above it‼
It ain't a "stove", it's a forced air furnace... I try and keep heat "radiation" into the basement to a minimum, and maximize heat "conducted" to the forced air going upstairs. I'm having no problems keeping my house comfortable...
Run the stove (furnace) full?? Holy crap man, that would melt the paint off my living room walls.

It might work over there in PA where the outside temps are warmer but here in the UP it dont't cut it with the weather we've been having.

Another point to be made...
There's a huge difference between one or two consecutive days of sub-zero (or even single digit) temperatures, and weeks of consecutive days.
*

 

[stihly dan]

Seems to me the solution should be easy. Have an epa stove with secondary or cat that works for many people. Then why can't the manufacturers make a manual air intake go under the coals like the smoke dragons. essentially getting the best of both worlds, the stove starts out epa efficient then when the wood dies to coals and not heating enough you can spin open the under air, closing the air wash getting the rest of the coals to HEAT at a high temp. The smoke will be gone so there is no wasted emissions or particulates. this could even be done automatically if they wanted to be fancy. If you don't need the extra heat, or don't have a mountain of coals you will never have to touch the air under control.

 

[firebrick43]

White spider ,wait what do you have??? You don't have a purpose built furnace you attempted to modify a stove into a furnace and it's not working to well???

If you heat the basement and insulate the walls so the are not pulling the heat out the were else does does the heat have to go? UP. Is that not where your house is, above your basement. Warm floors are actually more comfortable than warmer air. Many in Europe and Asia heat the floors directly and it's catching on here. If your feet are warm then the temp around your body can be cooler with the same feeling of warmth.

sorry I went back and reread the post and you did say furnace. My bad. I didn't even know there was EPA furnaces, I assumed that the Let me start off by saying I was tired when I wrote this and there was some small choice but important words I left out. thread was about stoves. I figured if you were lost in the 50's you would be getting up from watching your black and white tv while smoking your pipe and stoking the basement smoke dragon relying on the heat rising to move it.

With "my" setup if I load maple or cherry in finer split batches I don't have a coal problem. Oak, elm, or hedge I have to stir them after a few hours which really doesn't bother me during the evening. So I burn different wood depending on how it operates. Fall and spring I will burn one load of pine to knock the chill in the morning off and that's all that's needed all day .

 

[firebrick43]

Seems to me the solution should be easy. Have an epa stove with secondary or cat that works for many people. Then why can't the manufacturers make a manual air intake go under the coals like the smoke dragons. essentially getting the best of both worlds, the stove starts out epa efficient then when the wood dies to coals and not heating enough you can spin open the under air, closing the air wash getting the rest of the coals to HEAT at a high temp. The smoke will be gone so there is no wasted emissions or particulates. this could even be done automatically if they wanted to be fancy. If you don't need the extra heat, or don't have a mountain of coals you will never have to touch the air under control.

Maybe it's like the limiters on small engine carbs in that the EPA doesn't allow air controls that if left open all the time would allow the stove to burn out of parameters???? Just a WAG.

 

[dustytools]

I

(deep breath)
OK... I'll ask the question again.
How does, "using a faster burning wood that doesn't coal as much helps as doe a couple of splits in batches opposed to filling the stove", work when you're not there to "babysit" the stove??

Ive got an idea, move your computer down to the basement next to your furnace and you should have plenty of time to "babysit" it. .

 

[Chris-PA]

And I never said that‼

Yes you did, that is what comment #57 was all about. "Now, I won't argue that burning 30% more of the available fuel (in this case a portion of the particulate emissions supposedly not burned by a smoke dragon) will result in more heat... it flat has to result in more (generated) heat from the same amount of fuel loaded in a box. What I will argue is whether-or-not you receive, or realize, all of that extra heat in your home." was part of it - if that heat does not enter your home there is only one other place it can go - up the flue, which is exactly what you were going on about in most of that comment. Have you changed your mind now? Please explain where that energy can go if it doesn't go up the flue and it didn't go in the house?

I said if all else remains equal, a hotter firebox temperature means hotter gasses exiting.
It don't matter squat what sort of firebox it is, EPA or not, if ya' run the temperature in any particular firebox hotter, by any means whatever, the flue gas temperature also increases. And nothing short of magic can change that... and I certainly never claimed it wasn't true in a non-EPA box.

Only if the air control hasn't moved. If I stop the air inlet down and the secondary combustion kicks in, then the firebox may get much hotter but the volume of flue gases goes down. Or the flue may get hotter, but not in proportion to the firebox.

I don't use radiated heat to heat the living area of my home, I use conducted heat‼ Radiated heat is, for the most part, worthless, wasted heat for my application... that was the whole friggin' point that you obviously missed‼ It does near no friggin' good to radiate heat into the cold concrete walls of my basement to just be transferred to the dirt behind it... when I'm trying to heat my upstairs living area‼ And it's the same in my shop... It does near no friggin' good to radiate heat into the cold board walls to just be transferred to the outside. If blowing air over the firebox "kills" heat transfer... how in hell is it possible that I heat the living areas of my home with a forced air furnace??

All you've done is say the same thing I have... but with some sort of blinding attitude.
I know the mechanisms of radiated and conducted heat... but it don't matter cold squat how much radiated heat comes off the box if it's going where you can't use it. I have no friggin' use for radiated heat in my application... none, nada, zilch, zip‼ Radiation does very little to warm air directly, it passes through it until it strikes a solid surface. In my applications, heat radiation (from the box) is near worthless, wasted heat‼ It could just as well not even exist.
So... why don't you explain why all this extra secondary burn heat radiation, a very large share of which is passing through the glass door and not even warming the box, is "more better" for me?? And when the secondary shuts-down, the fire collapses into coals, and the primary heat transfer method (in an insulated box) is radiated through the glass door... exactly how is that "more better" for me??
*

And yet you bought a stove intended to transfer heat primarily by radiation, and have been so friggin' incensed that it didn't perform in an application where radiated heat is "worthless and wasted", that you've been on a tirade ever since. You post pseudo-scientific sounding twaddle trying to equate magnitudes and rates and non-related values, calculating hogwash and spaming every thread about how lousy these stoves are. People read these threads and think your BS is actually meaningful information. It isn't that complicated - one type burns at a higher rate for a portion of the burn, converts more of the energy in the wood to heat, but has a longer tail off at a lower heat output (especially with no adjustments). The other has a more consistent but lower output and sends more of the energy up the stack unburned.

You post about how these are "insulated boxes" that don't even use real firebrick (as if that mattered), yet here is your stove:

Only the bottom and sides are insulated (with real fire brick) - the door, top and upper sides are not and that steel can radiate fine, not just the glass door. At higher temperatures that rate of radiated heat transfer is very high. That's what it was designed to do, as a stove not as an heat exchanger to your air ducts.

If you require a more consistently high output rate because you have no thermal mass to store the higher output during secondary combustion, cannot tolerate any temperature changes, refuse to make adjustments during the burn, and have blocked any means of using the higher radiated heat transfer rate mechanism that occurs at high temperatures and want to blow huge amounts of air over the stove surface, then maybe a smoke dragon will heat your home better. The output rate will not be as high as during secondary burn and you will waste more wood up the stack unburned.

Not everyone has a setup so perfectly unsuitable for wood heat.

 

[Chris-PA]

We covered heat already. Temperature in the house is raised when energy (heat) moves up the concentration gradient (inside stove to outside stove). Heat cannot move fast enough in brutal cold when coals build up in an EPA stove for my liking. It might work over there in PA where the outside temps are warmer but here in the UP it dont't cut it with the weather we've been having.

During secondary combustion the temperature of the stove is higher and so the rate of heat transfer is higher. At the tail end is may be lower. It's pretty easy to add a couple of splits of something light (or smaller size) during that period to burn up the coals and kick in more secondary combustion. Poplar and sassafras work well for that, or small dry splits of ash or oak. You don't have to burn it like they did during the emissions tests (no playing with the controls or adding wood).

How big is the firebox on your stove?

 

[chadihman]

I have a highly efficient epa stove that heats my 2800 square foot home for 10 hrs on a full load of hardwood. I clean my chimney once a year and am certain I could clean it every three years and be Ok. Maybe its magic and if that's the case I love it! My neighbor has a smoke dragon that smokes all day and plugs his chimney a couple times a year. I keep my mouth shut but his and everybody elses stinky dirty stove is going to ruin our freedom to burn wood. Epa stoves take a little more work but if you size your stove to your house there shouldn't be any issues.

 

[flotek]

Don't confuse White spider with the facts .. He would rather make his own facts up playing a lawyering game of " leading the witness " You could ask him if the sky is blue and he'd tell you it's red or green just to argue .he probably could have insulated and better sealed his house in the time that he has spent justifying his points on here using technical jargon

 

[Whitespider]

I guess I'll just haf'ta flat come-out and ask you Chris-PA...
Exactly what part of, "if all else remains equal" are you not understanding??

Oh... and one more thing you obviously don't understand... I didn't buy it‼
*

 

[4seasons]

While several post have mentioned thermal mass for heat storage everybody seem to be ignoring the fact that there are stoves designed to do exactly this. Masonry heaters and rocket mass heaters both burn clean complete burns then use thermal mass to store the heat for release over hours. Because of the fast hot burn there are very few emissions and almost no smoke. Then after the fire is out the heat stored in the brick, stone, or cob is released into the house. Of course there are some drawbacks like having to start a fire once or twice a day, but because of the retained heat the draft starts almost immediately so starting a fire is much easier as I understand it. Also they are big, heavy and in the case of a masonry heater expensive. With a RMH people have been building them on the cheap and spending way less money than we can buy a wood stove for. And there are always the government regulations and insurance hoops that must be jumped thru, but I think the benefits far outweigh the drawbacks. After all the trouble I have had with my stove this year I am seriously considering building a RMH at my house. Oh did I mention that they burn less wood too. Since you retain your heat rather than send it up the chimney and because of the complete burn you can actually get most of the BTU's from you wood to be released into the house.

 

[Marshy]

Found a nifty site that talks about combustion efficiency and heat transfer efficiency. Check chapter 14, it has good examples of burn curves...

http://autonopedia.org/renewable-energy/woodburners/making-wood-stoves/

 

[Chris-PA]

I guess I'll just haf'ta flat come-out and ask you Chris-PA...
Exactly what part of, "if all else remains equal" are you not understanding??

Oh... and one more thing you obviously don't understand... I didn't buy it‼
*

You're stalling and trying to distract from the issues.

If your point was that if you build a hotter fire in the exact same stove with the exact same setting then the flue would get hotter, well sure - but who cares and that proves nothing. The discussion was about two different types of stove. You were clearly proposing that the the secondary combustion stove sends more heat up the flue (because you had to open your "stovace" up), and that this explains why "EPA" stoves can't heat like a smoke dragon, and that the EPA doesn't test for this as they only measure particulates. This is nonsense and I called you on it - my stove, which is very similar to the Spectrum, runs with a very small air inlet area and does not run high flue temperatures. The energy is not going up the flue.

Also, it is irrelevant if you bought it or someone gave it to you - the point was that you took a stove intended to transfer heat primarily by radiation (plus some conduction), built it into an air heat exchanger and blew lots of air across it which cooled off the metal and probably the firebox (stopping secondary combustion sooner), and blocked the radiative heat transfer (which would have been ineffective anyway due to the lowered surface temperatures). Now you state that you could not use the radiated heat anyway, but still complain about how it performed.

This is absurd. These secondary combustion stoves are not that complicated or difficult to understand, nor are they hard to use or ineffective. They do have slightly different heat output profiles over the burn cycle compared to a smoke dragon, but this is only a minor thing to deal with for the benefit of wasting less of the energy in the wood.

They may make lousy hot air furnaces, but I have not much knowledge of wood fired hot air furnaces (and not much interest). Do they make secondary burn hot air furnaces? A hot air furnace uses a media (air) which has very little thermal mass to transfer the heat energy from the furnace to the living space. Since there is no energy storage then the system relies entirely on instantaneous heat output from the stove and must move that air rapidly to the living space. This is unlike a water based system where the transfer media has a very high thermal mass, and is more accommodating of input temperature fluctuations. Therefore a hot air system is more appropriate in a fossil fuel powered system where you can have constant high output at any time. You could do better if you add a thermal mass at the stove end of the system, such as if you built the "air handler" that surrounds the stove out of masonry rather than sheet steel. This is effectively what I have, as the stove is in a basement room surrounded by stone, and I use the old oil-fired system air handler to move air through that room. The stone absorbs the radiated heat from the stove.

 

[stihly dan]

Hey, my furnace is a mass heater, hell it weighs 700lbs.

 

[chadihman]

My EPA stove was a win for my neighbors, the epa and mostly me. It gives me an amazing amount of heat and burns clean. What's not to like about that????
Last night my family came over for my daughters birthday party. I got some comments on how cool the blue dancing flames were in the stove. Its a very neat fire to watch when the secondary fire is in progress.

 

[Whitespider]

You're stalling and trying to distract from the issues.

Stalling?? Hardly.

Let me see if I have this correct??
I make a post arguing that just because a firebox manages to burn 30% more of the fuel available in a stick of wood doesn't necessarily mean you'll get 30% more heat in your home (which I still stand by).
And then you spin-off every direction you can from it, claiming I said certain things by inference, even (it appears) reading my mind. Then you bring up something totally unrelated, something I built, stating facts about it even though you've never seen it... or, for that matter, been within 100 miles of it.
And I'm the one trying to distract from the issues??

Well, the only issue, as I see it, is I said just because a firebox manages to burn 30% more of the fuel available in a stick of wood doesn't necessarily mean you'll get 30% more heat in your home, and you disagree. So what? I also disagree with your disagreement... but I ain't goin' on a tirade over it.
*

 

[firebrick43]

Stalling?? Hardly.

Let me see if I have this correct??
I make a post arguing that just because a firebox manages to burn 30% more of the fuel available in a stick of wood doesn't necessarily mean you'll get 30% more heat in your home (which I still stand by).
*

Your absolutely right, instead of 30 percent more heat from the smoke burn, you may get 49 Percent more heat due to the smoke burn and the additional baffles in the stove . IF you would have read the links you would realize that many EPA stoves have baffles that help hold the heat down in the fire box instead of going up the flue to get the secondary burn going and as a result allows the heat to more efficiently transfer to the surrounding air. There is a reason why most EPA stoves manufactures recomend double wall stove pipe, to get the flue velocity up even though the flue temp is lower due to less heat going up the flue. A single wall pipe may transfer to much heat and reduce draft below what is needed for good combustion.
But it may not apply to your debauchery of a stove, wait furnace, wait, oh never mind.

 

[Whitespider]

Your absolutely right, instead of 30 percent more heat from the smoke burn, you may get 49 Percent more heat due to the smoke burn and the additional baffles in the stove.

The baffle argument don't fly...
My DAKA smoke dragon furnace has a baffle.
It sits above the fire and forces the combustion gasses to go around it in front just above the door, no different than the baffle in my EPA certified stove. It does everything the EPA stove baffle does except one thing... it doesn't have secondary combustion air holes in it. Stove baffles were invented and used to improve heat extraction centuries before the EPA ever got involved. In fact, Benjamin Franklin used the baffle concept in his invention the Franklin Stove 243 years ago. So that puts us back to the secondary burn... and nothing more than that.
*

 

[brenndatomu]

Also, it is irrelevant if you bought it or someone gave it to you - the point was that you took a stove intended to transfer heat primarily by radiation (plus some conduction), built it into an air heat exchanger and blew lots of air across it which cooled off the metal and probably the firebox (stopping secondary combustion sooner), and blocked the radiative heat transfer (which would have been ineffective anyway due to the lowered surface temperatures). Now you state that you could not use the radiated heat anyway, but still complain about how it performed.

Do they make secondary burn hot air furnaces?

Yes, they do make secondary burn furnaces, they work pretty well. So what did spidey do that was that much different from a wood furnace??? I give 'im points for tryin. I say if he would have had a bigger firebox it would have worked a lot better, that stove was just too small.