Burn time / BTU output / Magically creating Energy

[Jags]

Nope Jags, I don't think I missed your main point at all. Go back and re-read my post, in my first sentence I agreed with your main point, but what I was commenting on was why you said you made the post in the first place, and that was your knee jerk reaction to recent post like “Yup, I can burn my stove for 20 hours”, and your statement "So What".
I then went on to say why long, though in-efficient, burns are important to some people, why they might make posts about their long burn times, and that they CAN actually heat their house (under certain conditions), unlike your bic lighter hyperbole.
So, now if I make a post that I can sometimes get 8 hour burns with my softwood your knee won't jerk so bad. However if I make the statement that I can heat my house on one load for 20 hours, when it is -10 F -23C outside, be careful that you don't knee yourself in the chin.

What you say is true (especially the part about kneeing myself in the chin. %-P ). And although you may be able to heat your home for 20 hours on a low and slow burn - efficiently or not - is NOT the point. You are making a statement that I AGREE with.

I agree that the "so what" statement may have been a little strong because it does have real world use, But that fact remains that a 60 pound load of wood only has so many BTU to give up.

 

[Danno77]

But that fact remains that a 60 pound load of wood only has so many BTU to give up. unless you split it with a Fiskars.

There, fixed. You are welcome.

 

[53flyer]

Going back to the original post that referred to 1lb of wood having X amount of BTUs- Moisture content has a big impact on BTUs available in that 1lb at 0% would obviously have a lot more potential BTUs than 1lb at 30% because to get to 1lb at 0% requires more wood.

Which is why I added in the 18% value for the calcs.

Yes I know. I wasn't saying you were wrong (I agree with your post). I was simply clarifying and replying to another post in the thread. It was a good post by you to clarify BTU's and burn times.

I "do" have a few Q's irt "the other" efficiency though. I'm talking about efficiency related to a stove delivering it's generated heat into the room/house. I'd like to think it's basically the same for all EPA multi-stage burning stoves but there will obviously be differences and I wish it was easier to discern them. My understanding is that most of the heat transfer occurs through the ceramic glass which makes it seem like a bigger window would transfer more heat but I'm sure it's not that easy. Any thoughts on this aspect? Anyone?

Another related Q stems from my dilemma irt cat vs. non cat. It has to do with something I saw in a Blaze King dealership which I was reminded of by Slow1's post (#16 in this thread). If a cat's main function is to re-burn gases and reduce emissions (same things non cat stoves do with their multi-stage burning) then why do I keep hearing things about lower flue temp associated with cat stoves? The dealer I mentioned had a demo set up where a 4" tall opening could be revealed in the flue pipe (approx 2 ft above the stove/flue connection). The point being that you could expose the opening and insert your hand into the pipe to see how cool (relatively) the flue stayed.

Slow1 described the same thing in his post and it "does" make me think that if less heat is in the flue it must be going somewhere else like into the house "possibly"? Even "if" it were true that more heat went into the heating space (which I don't think has been proven yet) I still wouldn't get is the "why" behind the whole thing because I don't see how it would make that big a difference when, as I mentioned previously, the cat's basic function is simply to re-burn gases just like non-cat's do and that shouldn’t have a big impact on reducing the flue temp should it? Additionally, "if" it were true and made that big a difference then all stove makers would start using cats and that doesn't seem to be the case. If the simple act of going through the cat was responsible for the reduced flue temp it would make me think the heat was somehow being “lost” but then there’s that whole “energy can not be created or destroyed” thing so I’m really confused. Any ideas or thoughts irt all this? Is there any verifiable evidence that would support the reason for the reduced flue temps? J e s u s (had to space out because website kept blocking his name), you seemed to be a bit scientific in your posts in this thread so maybe you have some ideas here? The heat exchanger mentioned in Jesus’s signature seems interesting but I’m on dial up so I haven’t looked at the video. I can’t wait for DSL but that’s another topic…

Honestly I’ve been leaning towards non cats but I’m still debating it and a lot of people here seem to like cat stoves. I was actually turned off by the BK dealer because he was touting a potential 48hr burn. That type of statement turns me off to a salesman because if you need to say seemingly bloated things like that it makes me question “anything” you say.

Thanks

 

[SolarAndWood]

Any ideas or thoughts irt all this? Is there any verifiable evidence that would support the reason for the reduced flue temps?

I'm a guy trying to heat the house not a wood heat scientist. My belief, not supported by any data, is that at medium to high burns there is little difference between a cat and modern non-cat. Cats, however, do allow a lower burn rate than a non-cat and remain reasonably efficient and minimally-polluting. These lower burn rates are the reason for the lower flue temps. These ridiculously long burn times being thrown around are from a very large firebox at a very low burn rate. My personal experience is that there is a lot of time that a 10K btu burn rate is appropriate for my house especially given that the stove sits right in the middle of the living space.

If you are trying to heat the house from the basement, have you considered a furnace or boiler?

 

[53flyer]

These ridiculously long burn times being thrown around are from a very large firebox at a very low burn rate. My personal experience is that there is a lot of time that a 10K btu burn rate is appropriate for my house especially given that the stove sits right in the middle of the living space.

The firebox size was what I was thinking as well. I mean, a 4+ cuft firebox will obviously be able to burn longer than a 2-3cuft box so that would seem to be the main reason the BK can get these long smolder times vs. other non cat stoves that typically seem to have much smaller fireboxes (more fuel in = longer burn/smolder). I say smolder but I'm not sure how far to the smolder side a cat actually gets. It seems like that's what's going on (a smoldering fire that puts out less particulates because the cat catches them which is why the cat needs blown out periodically). Does this seem accurate?

If you are trying to heat the house from the basement, have you considered a furnace or boiler?

Do you mean getting another heat source instead of (or to supplement) the wood heat? A typical furnace that uses ducting and fans to circulate the heat it generates?

 

[SmokeyTheBear]

--that reload frequency is set by demand, not 'burn time'.

Ding - Ding -Ding. I am in no way trying to slight stoves that have the ability to maintain a low and slow fire. I just want it to be perfectly clear that doing so just reduces the heat output of the stove. For many - that is a good thing.

But...I have seen a few claims on burn time and btu that led me to believe that some were squeezing btus out of their stoves that was never loaded through the door. ;-P

You just didn't notice that funny little symbol and data plate indicating that the stove is a mass to energy conversion device operating under extreme temperature and pressure.

 

[SolarAndWood]

53Flyer, the BK rarely has a flame. At higher burns it kind of glows, at lower burns it doesn't look like there is even a fire in it. When I think of smoldering, I think of old stoves and outdoor boilers blowing plumes out their stacks. When the cat stoves are at their low burn, there is nothing visible coming out the stack.

Definitely wouldn't recommend abandoning wood; was getting more at a wood add on furnace or a indoor wood boiler that would tie into your central heat. If you aren't successful moving heat from your current stove in the basement to the rest of the house, I would consider a wood furnace or boiler instead of a new stove.

 

[53flyer]

SolarAndWood- That's what I think irt smoldering as well. The way a chimney sweep explained it to me was that smoke and soot indicated a low temp fire that was wasting heat because that smoke/soot would otherwise be converted to heat if it was being burned up. What I wonder is this: does a cat stove not put smoke out the chimney when a non cat might do so simply because the cat is catching the smoke? I.e. it's still producing it but the cat holds onto it. That would mean it wasn't burning any more efficiently (from a BTU standpoint NOT an EPA standpoint) than a non cat stove that did have some smoke coming out the chimney and that the created smoke/soot was just as wasted in both types of stoves right?

 

[SolarAndWood]

The modern non-cat stoves are restricted so that you cant choke the fire down so low that you are blowing particulates out the chimney. The difference is the cat can still operate efficiently at these lower burn rates. My firebox can look completely void of fire yet the cat is glowing and the thermometer shows it well into the active range. That was the biggest selling point for me. I got a stove with a big firebox and big output when needed but could also burn at the lower rates needed the majority of the time. I'm not sure the stove will ever run wide open but we'll see come mid-winter when the wind is howling and the temps are below zero.

 

[Todd]

Going back to the original post that referred to 1lb of wood having X amount of BTUs- Moisture content has a big impact on BTUs available in that 1lb at 0% would obviously have a lot more potential BTUs than 1lb at 30% because to get to 1lb at 0% requires more wood.

Which is why I added in the 18% value for the calcs.

Yes I know. I wasn't saying you were wrong (I agree with your post). I was simply clarifying and replying to another post in the thread. It was a good post by you to clarify BTU's and burn times.

I "do" have a few Q's irt "the other" efficiency though. I'm talking about efficiency related to a stove delivering it's generated heat into the room/house. I'd like to think it's basically the same for all EPA multi-stage burning stoves but there will obviously be differences and I wish it was easier to discern them. My understanding is that most of the heat transfer occurs through the ceramic glass which makes it seem like a bigger window would transfer more heat but I'm sure it's not that easy. Any thoughts on this aspect? Anyone?

Another related Q stems from my dilemma irt cat vs. non cat. It has to do with something I saw in a Blaze King dealership which I was reminded of by Slow1's post (#16 in this thread). If a cat's main function is to re-burn gases and reduce emissions (same things non cat stoves do with their multi-stage burning) then why do I keep hearing things about lower flue temp associated with cat stoves? The dealer I mentioned had a demo set up where a 4" tall opening could be revealed in the flue pipe (approx 2 ft above the stove/flue connection). The point being that you could expose the opening and insert your hand into the pipe to see how cool (relatively) the flue stayed.

Slow1 described the same thing in his post and it "does" make me think that if less heat is in the flue it must be going somewhere else like into the house "possibly"? Even "if" it were true that more heat went into the heating space (which I don't think has been proven yet) I still wouldn't get is the "why" behind the whole thing because I don't see how it would make that big a difference when, as I mentioned previously, the cat's basic function is simply to re-burn gases just like non-cat's do and that shouldn’t have a big impact on reducing the flue temp should it? Additionally, "if" it were true and made that big a difference then all stove makers would start using cats and that doesn't seem to be the case. If the simple act of going through the cat was responsible for the reduced flue temp it would make me think the heat was somehow being “lost” but then there’s that whole “energy can not be created or destroyed” thing so I’m really confused. Any ideas or thoughts irt all this? Is there any verifiable evidence that would support the reason for the reduced flue temps? J e s u s (had to space out because website kept blocking his name), you seemed to be a bit scientific in your posts in this thread so maybe you have some ideas here? The heat exchanger mentioned in Jesus’s signature seems interesting but I’m on dial up so I haven’t looked at the video. I can’t wait for DSL but that’s another topic…

Honestly I’ve been leaning towards non cats but I’m still debating it and a lot of people here seem to like cat stoves. I was actually turned off by the BK dealer because he was touting a potential 48hr burn. That type of statement turns me off to a salesman because if you need to say seemingly bloated things like that it makes me question “anything” you say.

Thanks

Seems to make sence to me that the lower the flue temps the higher the efficiency, but maybe if you consider a higher flue temp stove with a long run of stove pipe in the mix it's a wash since the pipe will radiate a lot of heat into the room and create more efficiency? I've seen the video with the guy sticking his hand into the pipe of the Blaze King and those temps have to be below 200 degrees I would think to not burn yourself, my internal temps are much higher somewhere around 400-700 depending on the rate of the burn. I guess you can only steal so much efficiency to keep the draft going and Blaze King seems to be walking a fine line and also seems to need an exceptional setup to work correctly.

 

[Adios Pantalones]

some fancee cipherin' fo sho