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heating with green wood  RSS feed

 
                                      
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Brenda Groth wrote:

not sure how much you have studied..but it is best to cut your wood in the winter when the sap is out of the wood..so it is already drier..and then dry it out in the sun ..or under a tarp or cover to keep it from getting rained on.

then store it in a fairly open stack..with a few inches between cords when you put it up..this also helps the drying..mold can cause some serious health issues storing up wet wood.

best time to get your wood is in the winter..look for dead trees or cut them and leave them lie for a while if you have to..but get them off their roots in the winter before the sap rises.





Very good advice.

Ash that is cut in winter is one wood that is almost dry enough to burn immediately.
Always cut when the sap is at it's least. Winter.

 
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I know this is kind of dated but... several years ago I run a seasonal fishing lodge on the Gulf of Alaska. Since we were surrounded by forest service land we couldn't cut standing trees. Our camp was also low impact so we didn't have any permanent structures.  All we had for firewood was logs that washed up on the beach. About all we could do was run it hot and make use of a flu brush when things got scuzzy.
 
                                
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http://www.sredmond.com/vthr_index.htm

this is a very interesting paper about burning green woodchips efficiently. I think woodchip has a lot of potential over cordwood as a heating fuel; it is a by-product of lots of forestry processes and means that the large timber can be used for structural purposes.

It's interesting how his design runs contrary to a lot of the rocket stove designs. I'd like to see some more diagrams, and then I'd like to try adapting it to run continously, rather than in batch mode.

Anyway, his arguments about how green wood can be burned efficiently - in the right stove - are very interesting.
 
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ejoftheweb wrote:
http://www.sredmond.com/vthr_index.htm

this is a very interesting paper about burning green woodchips efficiently. I think woodchip has a lot of potential over cordwood as a heating fuel; it is a by-product of lots of forestry processes and means that the large timber can be used for structural purposes.

It's interesting how his design runs contrary to a lot of the rocket stove designs. I'd like to see some more diagrams, and then I'd like to try adapting it to run continously, rather than in batch mode.

Anyway, his arguments about how green wood can be burned efficiently - in the right stove - are very interesting.



I think this topic is worth a new thread.


 
paul wheaton
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One thing we have started to do with the office rmh is to stack firewood on the mass. So far, what we have stacked is already pretty dry stuff. I think that doing this is making it even drier, and, thus, even better fuel.

But I am curious to test setting up some sort of box that is relatively open on the bottom that can be set on the mass and firewood that is wrist size or small can be put in all jumbly. Then see how quickly it dries.

Another thing: Ianto had some sort of racks set up about a 18 inches above the barrel - suspended from the ceiling. He would put wood on those racks to dry. That would make me pretty nervous - but I suppose that in many cases, it could be relatively effective.



 
pollinator
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paul wheaton wrote:I think the optimal stacking would be to have it all vertical:  ||||||||||

It might be optimal to have an air layer between layers of wood.

But I just don't see an obvious, easy way to do something like that.  So - the jumble stack rules! 



So - Just bumping this discussion back up to the top. Well covered firewood is best !I have seen immensely tall stacks of wood with the core a jumble of

split logs and the shell being split wood stacked something like this

///lll\\\
//lllllll\\
//lllllllll\\
//lllllllll\\

This stacking seems more common among transplanted 1st 2nd generation North Europeans still burning wood!


As we now have the Wheaton Labs It would seem possible to start with one pile of just cut wood,divide that pile into two pallet loads worth. load it on to two

trailers and run them over the scales at ether a Big rig truck stop, or the scales where Bulk feed or coal or other bulk products are loaded Balance the Scales

(this assumes you know your trailers gross weights)

At the scales reshuffle part of the loads to pre balance their weights and then deliver the two loads to a location where simple set of scales can be made from
balancing one log across another !

Rearrange the to loaded pallets onto the see/saw scales with ether crisscrossed wood or Vertical stacks and weight to see which one dries out the fastest !

This can be as elaborate or large as you want,

A definitive answer to this certainly would be worthy of a paragraph in the daily Blog hint hint

Again, for the good of the Crafts ! Big AL

Late Note ; great minds think alike Paul W. stuck his post in just a head of mine ! A.L.
 
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Considering that wood loses most of its moisture through the end grain I don't see any benefit to vertical stacking. Seems to me it would protect the bottom end.
The better the ends are exposed to air flow, the faster the wood should dry.
 
allen lumley
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Peter Ellis : This is a long thread Extension, and even I skimmed through most of it! There is some anecdotal evidence for it, plus along history in many Northern parts
of the world for making great big 'Haystack' or 'Sugar Loaf' structures some with the outermost layers sorted and stacked with wood bark outer most !

I am going to remain open minded about this and suggest that it Be put to a scientific test

As I see it an equal amount of wood generally by Tree species but definitely by weight should be loaded say 250 pounds and 250 lbs should be placed on a home made
see/saw or balance beam should be stored inside and the one that dries fastest will show its self in no more than a few days !

For the Good of the craft ! Big AL
 
Peter Ellis
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http://www.backwoodshome.com/articles2/fluckiger132.html
Link to an article describing a holz hausen, a sort of bee hive stacking system, with an organized external shell and a jumbled interior core, which the author says he has found to be both a stable structure and a faster drying system than familiar linear stacks.

Allen, when it comes to subjects where one can safely wager that lots of research has already been done, I prefer looking for the results of that research over conducting my own experiments. Typically the researchers had access to better equipment and larger data samples than I can reasonably pull together on my own.

So in this case. I already knew from lots of prior reading that wood loses water faster through end grain than "cross grain". But that is faster per unit area, not necesarily absolutely faster. So, split logs will lose more water weight across the split faces than out of the ends, given equal exposure.

Water in wood exists in multiple forms, with something more than half being "free" and about a third actually tied up in the cells of the tree. The free water comes out readily, but you are left with another ten percnt or so you need to get out to bring your wood down to a good moisture level for burning.

That water is not going to flow out of the wood under influence of gravity. It takes evaporation to pull that stubborn part out. Most of the water coming out of the wood will leave by evaporation, but the part held in the cells is only coming out by evaporation.

This means a good flow of air with a lower humidity than the wood, that will pick up water from the exposed surfaces. As the surface wood dries, it pulls moisture from deeper in the wood. Eventually the moisture conten of the wood equalizes through the log and balances with the atmospheric humidity. Water content in wood, including furniture and structural timbers, as well as firewood, will vary depending on the humidity of the air.

So the secrets to getting dry firewood are surface area, air flow and relative humidity.

Apparently the holtz haus does a nice job of exposing surface area and encouraging air flow, resulting in a faster drying stack of firewood than our more familiar forms.
There are also lots and lots of pretty simple ways of doing a solar kiln to speed up drying, but in all cases the elements are exposed surface area and movement of relatively dry air across the exposed surfaces.
 
allen lumley
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Peter Ellis : You are preaching to the choir. basically I agree with everything you are saying With the possible exception of looking to tradition as a sufficient source
For providing verifiable Research ! The Holz hausen wood piles you show are simpler versions of multigenerational piles common in the French speaking parts of
Canada, The Adirondac's and upper New England !

My Point is that I do not believe this has been settled, This Thread / Thread extension is over 6 years old!

People who use a rocket stove are certainly not following tradition in their heating practices, But they are the most likely to properly prepare and store there wood,
compared to their neighbors with wood fired outdoor boilers !

If you had to nearly identical commercial apple storage bins Approximately 4' by 5' and 30'' high they could be weighed, and balanced closely to each other with the
addition of rocks! then a load of fresh cut and split wood could be divided into two piles, al cut at the same time you should have nearly identical water weight But
you only need to measure water lost and for that a simple balance beam, a indoor space less than 6' by 10' the loaded apple bins and two weeks time would prove
the issue !

This early in the heating season I do not have that much room even in my own living room ! For the Good of the Cause ! Big AL
 
Peter Ellis
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Allen, I may be preaching to the choir, but the choir is trying to write its own book of psalms, rather than working with what has already been written.
And I am not speaking about tradition. You are suggesting that we need to do an experiment. I am saying that with not terribly much research one can find plenty of experiments that have already been done. Some sorting through those experiments will almost certainly provide some that either match up neatly with what you are suggesting, or align closely enough to have tested the same questions.
We do not need to reinvent the wheel.
 
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Most trees have dead lower branches, albeit mostly kindling size, esp. ones planted close together. the dead branches are only superficially wet from rain or damp but dry inside if they are not rotten. These branches get blown off in heavy winds from time to time and can be identified as they snap not bend. Cherry pick this dry stuff.
 
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My question is about the most efficient way of collecting wood for a RMH.in My plan is to plant black locust in a permaculture orchard style layout. To get the most out of the black locust as a nitrogen fixer, I will coppice the tree as suckers reach about three feet long and use them as cut to feed an RMH.

My questions are about whether the prunings need to be debarked or if not how long would that change the drying times especially since I want to leave them so much longer than standard.

The alternate idea would be to create a system that would cut them down to 1/2" lengths to turn them into a pellet media.

The whole idea is to create firewood with minimal equipment and the least amount of labor and then burn them with the least amount of labor.

The reason I am interested is I am working on generating power with an RMH, so my fuel needs would be much higher than normal.
 
Peter Ellis
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Richard Hauser wrote:My question is about the most efficient way of collecting wood for a RMH.in My plan is to plant black locust in a permaculture orchard style layout. To get the most out of the black locust as a nitrogen fixer, I will coppice the tree as suckers reach about three feet long and use them as cut to feed an RMH.

My questions are about whether the prunings need to be debarked or if not how long would that change the drying times especially since I want to leave them so much longer than standard.

The alternate idea would be to create a system that would cut them down to 1/2" lengths to turn them into a pellet media.

The whole idea is to create firewood with minimal equipment and the least amount of labor and then burn them with the least amount of labor.

The reason I am interested is I am working on generating power with an RMH, so my fuel needs would be much higher than normal.



The name of the game is dry(er) air flow. Half inch long pieces are going to have a terrific surface to volume ratio for drying out, but in volume you will have to work out a way of exposing them. A substantial volume, say a cubic yard, of such pellets would have effectively no air flow in the center, while the same volume of three foot sticks would have air flowing through the entire volume.
I think debarking the sticks would not be a good use of energy.
I don't know how you would be cutting the sticks to half inch lengths, but would think that step would be a massive energy sink.
If I were going to organize something along the roug lines you've provided, I would bundle my sticks at harvest into bundles sized for my RMH. I would tie them with a jute twine that can go right into the fire. The bundles would be stored in a simple solar kiln to dry them out. With thin sticks and the heat and air flow involved with a solar kiln, each bundle should dry in a matter of weeks. Feed them into the solar kiln at one end, take them out at the other so you are always rotating stock and taking out the oldest bundles.

Minimizes handling, minimzes energy inputs, fast drying time.
 
Richard Hauser
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For cutting to length I was thinking about taking a band saw and putting it in a deli slicer arrangement. I have a band saw in my basement which has a tiny motor and it makes short work of anything I've fed through it because the blade is so thin.

Do you have any links for a solar wood dryer with continuous cross feed?
 
pollinator
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Peter Ellis wrote:

Richard Hauser wrote:My question is about the most efficient way of collecting wood for a RMH.in My plan is to plant black locust in a permaculture orchard style layout. To get the most out of the black locust as a nitrogen fixer, I will coppice the tree as suckers reach about three feet long and use them as cut to feed an RMH.



The name of the game is dry(er) air flow.
If I were going to organize something along the rough lines you've provided, I would bundle my sticks at harvest into bundles sized for my RMH. I would tie them with a jute twine that can go right into the fire. The bundles would be stored in a simple solar kiln to dry them out. With thin sticks and the heat and air flow involved with a solar kiln, each bundle should dry in a matter of weeks. Feed them into the solar kiln at one end, take them out at the other so you are always rotating stock and taking out the oldest bundles.

Minimizes handling, minimzes energy inputs, fast drying time.



I think this system would work well for the Scotcbroom that covers much of the 5 acres that Emerald Group is planing to develop. I think a row of pallets one on the ground and one fastened vertical at right angle with clear plastic roofing over the south face would work well.

 
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We built a 12.5' x 28' hoop house/greenhouse for the storage and drying of our firewood. It worked out very well and the cut split wood dries far faster than the tarped stacks we had done previously for many years.

Mine is different than most in that the floor/dirt is sealed with 6 mil poly and then covered with tar paper.

Also, there is an $18 box fan that runs on a thermostat, so it runs only when there is hot humid air to be removed. Both ends have a door and a window.

Cost was between 7 and 800 bucks.

There's a thread and pictures over at hearth dot com. Here's the actual thread:

http://www.hearth.com/talk/threads/i-built-a-12-5-x-28-greenhouse-to-store-and-dry-wood-working-awesome.129149/page-2



 
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Sounds like you made a macroscale solar dehydrator.
 
Troy Rhodes
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That is exactly what it is. A walk in solar dehydrator.


troy
 
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May be a bit late for you, but this year I was slow at building up my supply to burn.
This lead to a few experiments in expedited drying.
I attempted 3 designs (small scale) of solar kilns to see how well each worked.
All 3 work, but 1 beats out all the rest and I have decided which I will go with for next year.

I recognize a couple of names here from the discussion on Hearth.com and they have working kilns and great ideas.

My first was the basic Box Style.
Using a set of pipe staging I have around, I created a box structure and covered it with black plastic.
Basically building a hot box.
Loading the wood in the rear, sides and front creating an opening in middle to allow air movement.
I later changed out the plastic to clear and up'ed the efficiency of the process.
First lesson learned.. Clear!

My second was a basic clear plastic cover.
With a single stack and doing a 'lean-to style cover, on the ground in the front and open in the rear and ends.
To my amazement, this worked very well.
Lesson learned.. Single stack in direct sunlight, small area

The third is the best.
A small solar kiln built from plywood and a few pieces of glass I have around.
It holds a 'face cord' of wood and in 2 weeks (of good sun) will turn it from green to <20%
Obviously, as air temp gets colder, it takes longer.
Yet even at 28* outside I'm reaching temps >80* inside the kiln.

I mentioned that I recognized a couple of names here, and believe they both have 'round-top' style sheds.
This I believe is how I'm going.
Building a Kiln like my best design is expensive and for a third of the cost (and so much less effort) I can have a very good way of drying wood.
I do believe I can load up late summer and have good dry wood for the seasons burn.
Not to mention a good covering and a dry place to fetch wood from.
This would also have the advantage of a place to start plants early spring.

I know this doesn't help you much now, but can help for next year.

P.S. I still have wood drying out there and just loaded up last week with some truly green wood to see just how long it will take during the winter.
 
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Keeping in mind that water diffuses along the grain about 10 times faster than across the grain I personally think that one of the best ways to deal with needing to burn wood that is still very green is to work with wood chips. Chipping the wood drastically reduces the cross section of wood being dried while increasing the amount of end grain exposed.

I've already made a few wood chip burning rocket stoves that work pretty darn well and I've been toying with different ideas concerning a built in dryer that would hold a full batch of chips. If made right (above a heat source, not below; designed for air-flow, things like that) there's a good possibility of drying green chips to levels good for burning could be done in one burn cycle. I picture 1"-3" coppice wood being fed to a small electric (or in my dream world rocket stove generated steam) driven chipper about once a week and the resulting chips stored in a bin by the RMH. Dump the chips that have been in the drying basket since the last burn into the feed tube then fill the drying basket with chips from the storage bin. Light the stove, repeat when cold enough to warrant.

Doing it that way you maximize all the pertinent factors we can control regarding drying of wood: High temperatures, low wood cross-section, maximum end grain ratio and with proper design of the drying basket you should be able to get relatively high air flow.

This also minimizes the effort involved in dealing with your fuel: A small chipper could be mounted on a little trailer with a hopper; pull the chipper up next to the coppice and you cut however many shoots you need then feed them directly into the chipper, no bundling/stacking or cutting to length needed. Then drag your trailer over close to the RMH and fill your storage bin, or better yet have the hopper be your storage bin and swap the empty bin for the full one. That would pretty much be it, no splitting, wood small enough to be cut easily with hand tools, no long term wood storage taking up space. In my eyes there's lot's of pros to the system but I'm so enamored with it I have a hard time thinking of any real cons...
 
Peter Ellis
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Michael, it seems to me that the only downside to your system is the chipper. How do you recoup the cost? It is a relatively fragile link that needs maintenance and repair, are the time and cost there worth the benefits? It is an energy intensive approach, does it really save labor?

Mostly, I think, the problem of green wood is a scheduling issue. It can all be avoided with a bit of planning.

I am minded of something from a tv show, "Prairie House", I think? where they told the homesteaders any time you are not doing something else you need to be chopping wood for the winter.
 
Michael Newby
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Peter Ellis wrote:Michael, it seems to me that the only downside to your system is the chipper. How do you recoup the cost? It is a relatively fragile link that needs maintenance and repair, are the time and cost there worth the benefits? It is an energy intensive approach, does it really save labor?

Mostly, I think, the problem of green wood is a scheduling issue. It can all be avoided with a bit of planning.

I am minded of something from a tv show, "Prairie House", I think? where they told the homesteaders any time you are not doing something else you need to be chopping wood for the winter.



Wait, you mean not everyone has a 20" chipper sitting in their yard !?!?

Realistically, for material <4-5" a pretty sturdy simple disk type chipper could be made by someone whose handy with basic metal working skills (welding/drilling/grinding) for pretty cheap. Make it belt driven so you can use an engine that's being used as a power plant for multiple intermittent-use machines and you have an integrated system that should only need basic maintenance items such as greasing bearings and sharpening/adjusting knives. Heck, with the proper built in adjustments you could make a small chipper that could double as a planer; basically you'd just need to be able to switch from perpendicular feed for chipping to parallel feed for planing. I think that as long as you stack functions properly like that you could definitely justify the maintenance and repairs...

I personally could justify the system for myself with just what I've mentioned above, but for the entrepreneurial consider there's the fact that I regularly get paid to use my chipper to chip piles of brush others have made along with a good number of those people then paying me to haul away those chips.

 
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