yea, I figured that would catch someones eye- I'm talking about what size splits to burn. I just started burning a tarm 30 and it seems like the big splits cause it to idle or not reach temp. By big I would say 4x5 or so. Is it a matter of learning boiler vs. woodstove burn?
how big is your wood?
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I've been experementing with different sizes, and have actually found that I can get a better overnight with shorter, but fatter splits. If i load with 6 20" splits, after 7 hours i get maybe a 1" coal bed, not much heat and the house at 66-69. If I load with 9 14" splits (6 n-s and 3 e-w closest to the door) after 7 hours i get a 4-5" coal bed with some large coals, 72-74 temp in house.
I started off with all small splits on my tarm 40 a couple months ago and they were great. By small, I mean 14 to 20 inches long and about 2 to 4 inches thick with an occasionally larger piece. Now i have moved on to a different part of my stack with larger pieces - about 5 to 6 inches. I think the smaller ones were much better. The larger pieces have caused bridging a couple times. The small pieces burn hot and fast but that is ok for me since I have heat storage. If you don't have storage that may be a factor since you may not be able to deal with as much heat so fast.
Contrary to common belief, bigger is not necessarily better. It's more about how effectively you use it. Proper technique is important. People who are new to this whole issue place a lot of emphasis on making it last a long time, and bigger wood can help. However, it's actually more important to generate as much heat as you can with the volume of wood that you have. Smaller wood can provide more heat and less wasted energy, plus it's easier to handle, especially for other family members.
This is an area where storage really makes a difference. Without storage, you're always a bit concerned with trying to extend the burn time. This is not the best way to get peak efficiency. What you really want in a gasifier is effective secondary combustion throughout the burn. Larger rounds and splits have less surface area and therefor generate less wood gas. This can lead to weak or non-existent secondary combustion. You always want a coal bed over the nozzle.
If you take a big log and split it, it still has the same energy content, and it certainly does not burn less efficiently. EKO got their 90% efficiency test results burning 2" birch chips.
This is an area where storage really makes a difference. Without storage, you're always a bit concerned with trying to extend the burn time. This is not the best way to get peak efficiency. What you really want in a gasifier is effective secondary combustion throughout the burn. Larger rounds and splits have less surface area and therefor generate less wood gas. This can lead to weak or non-existent secondary combustion. You always want a coal bed over the nozzle.
If you take a big log and split it, it still has the same energy content, and it certainly does not burn less efficiently. EKO got their 90% efficiency test results burning 2" birch chips.
Quite possibly a dumb question but how does everyone measure their splits?? From the point of the split to the widest part of the log?? Widest spot across the front of the log?? or some other way. Ive always wondered but never really knew which is right??
"seems like the big splits cause it to idle or not reach temp"
Not sure what you mean there woodmiester.
Boilers idle when they reach their high limit
Not sure what you mean there woodmiester.
Boilers idle when they reach their high limit
I've read about 4" diameter is about the largest split that will air dry to the core? I know when the labs test wood burners for certification they use x pounds of 4" blocks of red oak as the fuel, for equal comparisons.
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Most of my logs were 16-18 inches round split into quarters. The manual says 8 inch max, the quarters were about the recommended size but the gasifier didn't reach temps above 150*. I re split them the quarters onto one or two more pieces, yes they burn faster but very hot and the storage gets up to temperature quicker with smaller pieces. I'm sick of swinging an ax in my basement, I'm going to buy an electric splitter for this reason.
I can use up to 25in. but i find that the 18-20 in works better.Most of my wood is square split because its easier for me to get the stove loaded at night
Bigger is better. The real big stuff I only split in half, then stack them up three pieces high, flat side down, with a slight lean towards one wall of the firebox so the stack doesn't fall over. The fire burns up through and as it does the wood drops and it feeds itself in a sense. This is the only way I can get over 5 hours of burn time.
On the other hand, if I add a bunch of smaller 4-8" splits, I have an inferno that's hard to control.
On the other hand, if I add a bunch of smaller 4-8" splits, I have an inferno that's hard to control.
ManiacPD said:
That's absolutely true for traditional boilers and furnaces. I've been there. Gasifiers behave differently, and gasifiers with storage are even more different. That's what my comments were aimed at. However, I expect that in any wood burning appliance a hot fire generates more BTU per pound of wood than a slow fire.
nofossil, I hear you. You guys that turn wood into gas THEN burn it are years ahead of us old-school boiler types.
I would think a smoldering log with unburnt gasses (ie, energy) going up the stack as soot or making creosote aren't doing you any good towards your mission to heat water.
I really need storage to maximize my boiler's capability. But if what I read today about oil going to $25/bbl next year it may be tough to justify burning wood, never mind investing more money in my system. I'm sure that constitutes blasphemy towards wood burning so I'll be careful...
I would think a smoldering log with unburnt gasses (ie, energy) going up the stack as soot or making creosote aren't doing you any good towards your mission to heat water.
I really need storage to maximize my boiler's capability. But if what I read today about oil going to $25/bbl next year it may be tough to justify burning wood, never mind investing more money in my system. I'm sure that constitutes blasphemy towards wood burning so I'll be careful...
ManiacPD said:
This is true, but on the other hand we know that these prices are short lived. Its the time to just look around and keep your eye out for really good bargains on the supplies you will need to hook up to storage. With the scrap prices down, you may even come up with a cheap storage container.
I am hoping/thinking that this will at least make it very easy to find good wood to burn. All the would-be wood burners may just decide to slack off and burn oil leaving the wood for us.ManiacPD said:
Good question, I had wondered the same thing. If you figure most splits are either square cross section or triangle, you can just take the average side of the square or triangle.lawandorder said:
I do not regret burning wood for the last 26 years in one form or another. Wood will warm you in many ways, when you buck it up , when you split it, when you stack it, when you lug it into the house, and when you burn it. Even if oil (blasphemous word) ;-) got to less than $25./bbl I'd never go back. Most of my splits are 4 to 6 inches and 3 years dry. sweetheat
I'm pretty new to this whole thing but what I'm finding is that as I'm looking at my wood pile I must have been getting sick of splitting because I have much bigger pieces then I had planed on. What I'm finding though is that I put in a few smaller splitts say up to 4" across and then a few larger ones on top and my boiler is getting up to max temp and the fan is shutting down. That seems to tell me that the larger splitts are working fine. I don't need to generate more heat in the wood box because my boiler won't take it.
I have found that on a couple of occasions there has been some bridging that I've poked down but that doesn't happen all the time.
I have found that on a couple of occasions there has been some bridging that I've poked down but that doesn't happen all the time.
free75degrees said:
My EKO manual states "measured across any surface" when speaking of split size and recommends nothing larger that 7". So if it's square, round, triangular or what ever the general reference is to largest surface area when speaking of splits. Going by the manual I have found that logs larger than 7" do have a tendency to "hang up" and burn less efficiently. But I have also found using smaller splits on the bottom of my fire and building up to larger splits (still avoiding the maximum) I get a longer sustained output from my fire.
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