Warm Winter = reduced wood burned?

jebatty · Dec 31, 2011

This one took me by surprise. This winter has been very warm compared to last, at least that's my perception. After checking the amount of wood I burned Nov+Dec/2010 with the same for 2011, I find that last year I burned 3143 lbs of aspen/pine and this year I burned 3014 lbs of aspen/pine. However, last year I started heating in Sept, but this year the first firing was mid-October. I can only conclude that based on temperatures during these two periods, heat loss did not vary by much. Maybe the best news is that so far this year I have burned only 1.36 cords. My estimated need for the 2011-2012 heating season is 4 cords.

Duetech · Dec 31, 2011

Ditto on the 2010/11 season September start up. I would like to agree there has been less fuel going into my boiler but 1/2 way through last season I discovered a more efficient method of loading my boiler (about 33%) so I would only be able to present skewed comparisons. We have had a couple of cold stints and one down to 11*f so I did see some comparison. I burned 12 cord last year and had that much on hand at the start of this season. The difference I can point out is last year most of my wood was dense hard wood and this year only about 1/2 of it is dense. With mixed usage I have used about 2- 2 1/2 cords and that would equate to just about 1/2 of what I used by this time last year. In a seemingly selfish approach I kind of like the trend. However in 1985 we had an ice storm on New Years Eve night and we have one sort of forcast for tonight that is supposed to blow until 9 pm of Jan 2, 2012. Got my nose broke by a falling tree trying to help a neighbor who insisted on doing things his way in the 1985 storm so this storm has my interest. Hopefully I'm safe this time... I have caller ID.

henfruit · Dec 31, 2011

Jim, On a full load of pine how many hours can you get of burn time? How long do you store the pine before you use it.

Thanks
Henfruit

goosegunner · Dec 31, 2011

One thing I noticed when burning red pine and spruce was an abundance of sparks compared to the red oak. I do think the pine burned hotter giving better out put but over a much shorter time. Only future tests will tell me for sure.

gg

jebatty · Dec 31, 2011

henfruit said:
Jim, On a full load of pine how many hours can you get of burn time? How long do you store the pine before you use it. Thanks Henfruit

A pine load will typically be 2 to 3 hours. All my wood is split, stacked, and shielded from rain and snow for at least two full summers. It is dry.

infinitymike · Dec 31, 2011

jebatty said:
I find that last year I burned 3143 lbs of aspen/pine and this year I burned 3014 lbs of aspen/pine. .

I'm confused. I have read about people weighing their loads but doesn't weight vary on moisture content? So a cord of freshly c/s/s will weigh more then the same one a year of two later? How does weighing wood help? Always looking to learn something new.

infinitymike · Dec 31, 2011

As far as the weather, it's absolutely ridiculous here. For the most part its been in high 40's to low 50's so far. today I was wearing a t-shirt outside helping my friend move.
I've been heating the house up before bed, shutting off the t-stats and boiler, waking up and getting boiler to temp and heating house up again, that will last until late evening. Real good for me considering all my fuel was c/s/s this sept. With all that said I've still burned about 1.75 cord. Mostly maple, some cherry and locust. Oh yeah some doug fir framing scraps also, about an 1/8 of a cord.

woodsmaster · Dec 31, 2011

Don't Know havn't had any cold weather to compair with since system has been fully operational. Not complaining. Have a couple of cold days coming soon to give it a test.

jebatty · Dec 31, 2011

In the early days with the Tarm I prayed for cold weather, really cold weather, because I had so much fun operating the think. Still enjoy that, but things go good when I only have to burn every 3rd day or so.

jebatty · Dec 31, 2011

Iâ€™m confused. I have read about people weighing their loads but doesnâ€™t weight vary on moisture content? So a cord of freshly c/s/s will weigh more then the same one a year of two later? How does weighing wood help?

Yes, weight varies with MC. Sometimes freshly cut weighs more than twice that of bone dry wood. "Seasoned wood" means, or should mean, wood at or about 20% MC. Not bone dry, but feeling very dry to the touch and by appearance. And wood at 20% MC burns very well in a gasification boiler, wood stove, or anywhere else.

Wood at 20% MC has available heat content of 6050 btu/lb when burned at an internal stack temperature of 400F. This is a pretty good approximation of what should happen in a well functioning wood stove or gasification boiler. Now, if the stove or boiler is 82% efficient in delivering available heat to the environment or water, etc., that equates to delivered heat energy of about 5000 btu/lb. But pick your own %.

So, with my Tarm and 1000 gal of storage, if the water in storage is at 140F and I want to burn enough wood to end up at 185F, I now know I need to burn this much wood by weight: (185-140) x 8.33 x 1000 / 5000 = 75 lbs. That's what weighing wood is all about in my case. I always weigh my wood, have an easy scale setup, and it tells the truth on how much wood I actually am burning. I guess I might be a geek on things like this, but it only is fun for me.

Duetech · Dec 31, 2011

infinitymike said:
jebatty said:

I find that last year I burned 3143 lbs of aspen/pine and this year I burned 3014 lbs of aspen/pine. .

Click to expand...

I'm confused. I have read about people weighing their loads but doesn't weight vary on moisture content? So a cord of freshly c/s/s will weigh more then the same one a year of two later? How does weighing wood help? Always looking to learn something new.

Most btu charts (wood type/weight/btu per cord) work off a wood moisture content. For practical purposes 20% seems a favorite number. If all your wood is at the 20% mark when burned you have a fixed referrence for data comparison. 30% moisture pine will not generate the same number of usable btu's as 20% moisture pine even if it takes longer to burn. It's kind of like removing one spark plug wire from your car. It will still run but the mileage goes down and the gas consumption goes up. The negine has to work harder to try to make up for the lost power. So your confusion is because you understand the varying moisture and weight relation. Some people don't and don't see the relevance of the data. Weighing the wood only gives dependable data when the wood moisture is steadily at a fixed % rate. At 20% more of the wood catches fire sooner and puts out heat sooner than 30% wood. Wood stoves/boilers/gasifiers just don't burn water.
Oops Jebatty beat me to it.

infinitymike · Jan 1, 2012

jebatty said:
Iâ€™m confused. I have read about people weighing their loads but doesnâ€™t weight vary on moisture content? So a cord of freshly c/s/s will weigh more then the same one a year of two later? How does weighing wood help?

Click to expand...

Yes, weight varies with MC. Sometimes freshly cut weighs more than twice that of bone dry wood. "Seasoned wood" means, or should mean, wood at or about 20% MC. Not bone dry, but feeling very dry to the touch and by appearance. And wood at 20% MC burns very well in a gasification boiler, wood stove, or anywhere else.

Wood at 20% MC has available heat content of 6050 btu/lb when burned at an internal stack temperature of 400F. This is a pretty good approximation of what should happen in a well functioning wood stove or gasification boiler. Now, if the stove or boiler is 82% efficient in delivering available heat to the environment or water, etc., that equates to delivered heat energy of about 5000 btu/lb. But pick your own %.

So, with my Tarm and 1000 gal of storage, if the water in storage is at 140F and I want to burn enough wood to end up at 185F, I now know I need to burn this much wood by weight: (185-140) x 8.33 x 1000 / 5000 = 75 lbs. That's what weighing wood is all about in my case. I always weigh my wood, have an easy scale setup, and it tells the truth on how much wood I actually am burning. I guess I might be a geek on things like this, but it only is fun for me.

Thanks. I guess i am a "geek" also that kinda stuff really interests me. I have keep a log (no pun intended) of how many splits I've burned each time and what outside temps were.
I have re-split many splits through out the pile to see what MC was and believe it or not it was mostly 22%-24%, some pieces were relatively light for there size and some of equal size were a lot heavier. I have never had an internal stack temp higher then 300*. Should I have a higher stack temp? If so how do I get it hotter? will that couple of percent of moisture make the difference?

jebatty · Jan 1, 2012

I have never had an internal stack temp higher then 300*. Should I have a higher stack temp?

300* usually is the minimum needed in the stack to prevent condensation in the stack or in the hx tubes in the boiler. If you are not having any condensation, I would guess you're OK. Or, perhaps where or how you are measuring stack temp is providing an inaccurate reading; or your measuring device/thermometer is not calibrated or is in error. Personally, I would not be comfortable at the 300* number. On the other hand, I wish my boiler would produce rated output at 350* or so, it won't, but it really purrs when in the low 400's.

infinitymike · Jan 1, 2012

jebatty said:
I have never had an internal stack temp higher then 300*. Should I have a higher stack temp?

Click to expand...

300* usually is the minimum needed in the stack to prevent condensation in the stack or in the hx tubes in the boiler. If you are not having any condensation, I would guess you're OK. Or, perhaps where or how you are measuring stack temp is providing an inaccurate reading; or your measuring device/thermometer is not calibrated or is in error. Personally, I would not be comfortable at the 300* number. On the other hand, I wish my boiler would produce rated output at 350* or so, it won't, but it really purrs when in the low 400's.

Here are a couple of pics showing the thermometer. It is 24" off the fly ash collector. I do get condensation in the ash pan. Its so bad it actually drips out of the pan onto the floor.I don't think I have anything but mucky muddy ash in the pan. I posted a thread a while back "puddles in my ash tray" I was told that it is because my unit is in the garage, which other then the radiant heat from the unit, is unheated and the black pipe, even though it is double wall, is uninsulated. I should insulate the pipe and the fly ash collector and that should stop it. But that may only be part of the problem maybe the low temp is also part of the problem. I didn't calibrate it. How do I calibrate it? Should I lower it? Maybe put it right at the bottom of the pipe above the fly collector?

On another note do you think weighing my wood would give me any good info if I don't have storage(YET). I plan on getting 1000 gals of pressurized storage by next season.

By infinitymike at 2012-01-01

Clarkbug · Jan 1, 2012

Mike,

You are measuring the outside temp of your pipe, not the actual temperature of the gases inside the pipe. This is also enhanced by the fact that you have a double wall pipe, so you dont know what the temp of the inner pipe is....

The weighted wood burns typically help when you are charging storage, since its a constant burn, and a known value for BTUs. My understanding of your Wood Gun is that it cycles in response to the load, so while weighing the wood will be helpful, it wont serve the usefulness that Jim discussed above.

infinitymike · Jan 1, 2012

Clarkbug said:
Mike,

You are measuring the outside temp of your pipe, not the actual temperature of the gases inside the pipe. This is also enhanced by the fact that you have a double wall pipe, so you dont know what the temp of the inner pipe is....

Yes the wood gun does cycle "on and off" in response to heat demands. I agree with you that it wont give me any useful data because the demands are different at any given time.

On the other hand, it is a probe thermometer. So either it is too far away or not calibrated to give accurate info or it is accurate, I only have 300*.
I have no idea. So any advise will be helpful. Now if it is accurate, how would I get hotter flue temps and is it really necessary?

jebatty · Jan 1, 2012

You can try vigorously boiling water and measure the temperature with your probe. That is a known number of 212. If its off from this, you can turn the dial on your thermometer so that it reads 212. Other than boiling water, you would need a known reference temp (ovens are not too good either) at any other temperature.

Clarkbug · Jan 1, 2012

infinitymike said:
Yes the wood gun does cycle "on and off" in response to heat demands. I agree with you that it wont give me any useful data because the demands are different at any given time.

On the other hand, it is a probe thermometer. So either it is too far away or not calibrated to give accurate info or it is accurate, I only have 300*.
I have no idea. So any advise will be helpful. Now if it is accurate, how would I get hotter flue temps and is it really necessary?

Whoops. Sorry Mike, I thought that was one of those magnetic ones meant for single wall pipe. My bad.

Have you checked the flue gas temp if you were burning something like scrap lumber, pallets, or bio bricks? Since that should be moisture-free fuel, you would be able to at least remove one variable...

Insulating your pipe wouldnt hurt, but then again we have also had pretty mild temps in this part of the world. Maybe when we get the cold snap later this week and you have a more constant demand, you will see the temps go up.

ISeeDeadBTUs · Jan 2, 2012

Because I'm too cheap to tap into my Oak piles, I tend to go get old tops and burn them a week later. Long short of it, I never really know how much wood I burn. I feel like its the same amount this year, though I actually started about a week earlier this year.

The BIGGEST difference though, is that 90% of what I've burned has been pine slab this year. Which allows me to gather/stockpile 'real' wood.

I have a friend that is a stove burner, and they say they have used just as much wood as last year. Makes no sense to me unless the wood is lower quality, or the inside temps are hotter than last year. Or . . . someone left a window open . . . :wow:

infinitymike · Jan 3, 2012

ISeeDeadBTUs said:
90% of what I've burned has been pine slab this year.

I must have heard that term a 100 times. But what exactly is slab wood?

Clarkbug · Jan 3, 2012

infinitymike said:
I must have heard that term a 100 times. But what exactly is slab wood?

When you get a round log onto a saw mill, and you cut off the outside of it to get a flat surface, the waste wood is referred to as slab wood.

This site has a good photo.

http://www.gloswoodfuels.co.uk/suppliers/

JayDogg · Jan 3, 2012

jebatty,

I noticed you have a solo 40, same as me. The past couple burns, I have not been able to get my burn temps up and have been having a hard time getting a hot fire. I am basically using the same wood I always do but for some reason it just takes way longer than normal to get a hot fire going. This is my 3rd season using the boiler and I have not cleaned out any air holes or anything like that other than the normal ash cleaning out of the fire box, secondary chamber and hx tubes. Have you run into this before? Wasnt sure if there are any air holes or anything else I should clean out, not really sure what else to try.

jebatty · Jan 3, 2012

Other than the cleaning you describe, you might check the draft fan to make sure that the damper position has not changed and that the fan is not clogged by dust. I pull fly ash out of the gasification area frequently and do not let it build up much in the tunnel. I partially empty accumulated ash out of the firebox every 2-4 weeks. I brush the hx tubes about 2x per month. Is your chimney becoming clogged? An elbow collecting lots of flyash and restricting flow? Is the slot in the firebox clogged? Is there a chance your current wood has a much higher MC?

Is your recent weather warmer? higher humidity? different from "normal" burning weather. I notice in warm temps and/or high humidity that getting the Tarm into a good burn takes longer. Also keeping a pretty good ash bed in the firebox helps, and only at the end of the burning season do I clean the firebox completely.

You also might try more kindling to get a good roaring fire before adding much wood, then a partial load until a coal bed is built up, and then a full load. Keep your splits relatively small, especially if you have not built up a good bed of coals

I burn almost only aspen and pine and have very little experience with other woods.

Hope this helps. Happy New Year!

ewdudley · Jan 3, 2012

JayDogg said:
The past couple burns, I have not been able to get my burn temps up and have been having a hard time getting a hot fire. I am basically using the same wood I always do but for some reason it just takes way longer than normal to get a hot fire going.

Maybe your draft is little weak, with the warm temperatures in the late fall I've been needing to run the draft fan faster than normal to maintain as hot a fire as I'd like. No problem last night though!

--ewd

JayDogg · Jan 3, 2012

The only thing is maybe the wood from this pile is a bit larger than the normal size which I typically burn. It is a pile of mostly oak and has been sitting for 2+ years so it should be plenty dry. I checked a couple pieces last night after I split them in half and they were around 18-20%. I will try some from a different pile tonight and see what happens. I pull fly ash from the bottom of the hx tube tunnel before every burn so I know thats clean.

Warm Winter = reduced wood burned?

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