Anyone build/use a solar firewood drying kiln?
http://www.builditsolar.com/Projects/WoodDrying/wood_kiln.htm
http://www.builditsolar.com/Projects/WoodDrying/wood_kiln.htm
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Augie
Feeling the Heat
Yes, I have mentioned it a few times and usually I am ignored or branded a heretic! 
I have used one successfully to season Oak from the mid 50's to just under 20 percent in 4 months.
Mine is much simpler, I use clear plastic and scrap wood to make a frame that is attached to the wood I am looking to season. Cost is about $20 for 2 cord(plastic cost) but I can use the plastic a few times I think. I am getting ready to cover the second two cords for next year. I think with this method I will not have to keep more than one year ahead at any time.
I have used one successfully to season Oak from the mid 50's to just under 20 percent in 4 months.
Mine is much simpler, I use clear plastic and scrap wood to make a frame that is attached to the wood I am looking to season. Cost is about $20 for 2 cord(plastic cost) but I can use the plastic a few times I think. I am getting ready to cover the second two cords for next year. I think with this method I will not have to keep more than one year ahead at any time.
Yes, I have mentioned it a few times and usually I am ignored or branded a heretic!
A heretic? I dunno about that. Maybe a wood tic...
What you are doing is what I am thinking of doing here. Cover up racks that I already have stacked with a frame and greenhouse plastic and fast dry them. Wood already takes up a lot of space here, and we cannot all be like Scotty the Overkiller. I have room for 5 cords and I burn about 3 cords a year. I am also above the 45th parallel and it rains a lot here (about 100 inches on average) . I have a hard time drying wood in the short (somewhat dry) PNW summers. Covering them with plastic and venting them properly seems to be the trick, to get them nice a toasty and deal with the condensation that forms ~inside~ the plastic.
How do you attach the frame to the seasoning wood? I have wood drying in double rows 12' long, and raised up on pallets and staked with t-posts at the ends. I cover then with tarps, flat on top in the summer, and fully wrapped in the winter.
MrWhoopee
Minister of Fire
Forest Service Study:
(broken link removed)
"I don't make this stuff up, I just report it."
Gallagher
(broken link removed)
"I don't make this stuff up, I just report it."
Gallagher
Two issues... one, they are 'drying' impossible to dry unsplit birch, and two they were testing in very high latitude Alaska. I realize that birch is one of the few firewoods available in Alaska, but if I leave birch here unsplit, it will rot before it dries out, regardless. So I do not think that is a good test for this type of solar kiln.
I would like to see results from lower latitudes using a different species and of properly ~split~ hardwood. Oak, Alder, Maple, something else. Then I would believe it, but until then my engineering background tells me that a warmer solar kiln will effectively dry wood faster than without one.
I also saw Gallagher film one of his movies in Sand City, CA... from under a plastic tarp, of course, and the smashed watermelons flew by.
MrWhoopee
Minister of Fire
Agreed. It is, so far, the only relevant study I've been able to find. My only thought on the subject is that the kiln must be somehow ventilated to remove the moisture while still holding the heat. One of the east coast, lots of oak people should do something similar. Anyone? Anyone?
barnuba
Member
Here is the kiln that I just built:
https://www.hearth.com/talk/threads/labor-day-wood.113026/#post-1507473
https://www.hearth.com/talk/threads/labor-day-wood.113026/#post-1507473
Augie
Feeling the Heat
I have posted a white paper from Cornell a few times that contradicts the Forest Survey. It is what I used to base mine off of. studyhttps://www.google.com/url?ttp://ww...ting/CC Accelerated Seasoning of Firewood.pdf
Over the years I have run across a few articles talking about speeding up the drying process with a kiln, plus Augie posted his before, what exactly are you looking for?
I am doing a test this season. I moved my stacking area two years ago with my usual top covering. Seems the ground under the new area stays wet. When I moved the stuff into the shed in April like I always do a lot of that oak was wet. 
I had just put a solar powered gable fan in the attic replacing the AC powered one that crapped out. In June I had the roof replaced and ridge vent installed so I took the solar attic fan out of the attic and installed it in the front of the woodshed and when the sun is out it blows into the shed. Been doing it all summer.
Hope that does drying stuff.
I had just put a solar powered gable fan in the attic replacing the AC powered one that crapped out. In June I had the roof replaced and ridge vent installed so I took the solar attic fan out of the attic and installed it in the front of the woodshed and when the sun is out it blows into the shed. Been doing it all summer.
Hope that does drying stuff.
HDRock
Minister of Fire
I'm with ya man ,going to try it next summerYes, I have mentioned it a few times and usually I am ignored or branded a heretic!
I have used one successfully to season Oak from the mid 50's to just under 20 percent in 4 months.
Mine is much simpler, I use clear plastic and scrap wood to make a frame that is attached to the wood I am looking to season. Cost is about $20 for 2 cord(plastic cost) but I can use the plastic a few times I think. I am getting ready to cover the second two cords for next year. I think with this method I will not have to keep more than one year ahead at any time.
My shed is similar. I installed a 1200 cfm roof fan. I drilled holes in the side of the shed just below the eaves into each stud bay. Then i put up walls in the shed leaving a gap at the bottom, so the fab draws air in the holes, down the stud bay, through the wood from the bottom up and out the fan. I'm hoping in winter it'll dry even better with the lower humidity.
I don't have a moisture meter, but its definitely drying some wood.
I don't have a moisture meter, but its definitely drying some wood.
HDRock
Minister of Fire
Sounds like a good idea thereI am doing a test this season. I moved my stacking area two years ago with my usual top covering. Seems the ground under the new area stays wet. When I moved the stuff into the shed in April like I always do a lot of that oak was wet.
I had just put a solar powered gable fan in the attic replacing the AC powered one that crapped out. In June I had the roof replaced and ridge vent installed so I took the solar attic fan out of the attic and installed it in the front of the woodshed and when the sun is out it blows into the shed. Been doing it all summer.
Hope that does drying stuff.
MrWhoopee
Minister of Fire
There was a problem with that link, but I found it.
(broken link removed to http://www2.dnr.cornell.edu/ext/info/pubs/Harvesting/CC%20Accelerated%20Seasoning%20of%20Firewood.pdf)
Good info, and pertinent to the parts of the country where humidity is high(er) and hardwoods season slowly.
I wouldn't say that it contradicts the other study, since the wood was a different species and was split. These kind of details can result in large differences.
It is somewhat limited in scope, did not have a control group and provded no actual data, but is still very encouraging. Much more promising than the Alaska study. I would like to see someone take a batch of green oak (both split and small diameter unsplit rounds), divide it into 2 stacks side by side and construct a solar kiln over one. Then take moisture measurements over the course of a summer. Based on this white paper, I suspect it would be beneficial for people with limited storage space to build solar kilns.
Mr A
Minister of Fire
For the East Coast , I am thinking your freezing temperatures over multiple days and weeks may hinder the progress of your wood drying. I may have mentioned before, I oak rounds up to 2 ft. across that are seasoned in 1 year. I collected them sometime earlier this year. If I remember right, this stack of oak was cut last September '12. I just split it yesterday, Harbor Freight Moisture Meter says 10%-15% in the center. It is Blue Oak. As long as we're looking for experiment ideas, I would try digging a compost pit to generate heat, build the greenhouse to include the wood stack and compost pit, the wood will not freeze and maybe it will season a lot faster.
I think that Cornell trumps the Forest Service. My parents met at Cornell...
Also the Forest Service 'study' says that birch bark is virtually waterproof, so I do not see how they can come to any conclusion like the ones they do. Its a poorly designed test, with an even worse conclusion. All they prove is that birch does not dry if it is left unsplit, which a lot of us have independently verified. I see little if any value in that, really. Its typical of the government though, like the EPA testing wood stoves in a way that no one uses them. And I mean no one burns wood that way, save for the testing places, 3 of which are here in the city nearest me.
HDRock
Minister of Fire
Wood will dry even in freezing temps. I have studied all kinds of effects of snow and ice melt in avalanche training for the ski patrol.
I like the intro to the Cornell paper, they spell it out, to paraphrase: You can speed up wood drying time by cutting pieces shorter, splitting them smaller, stacking for maximum solar and wind exposure, keeping the rain off and keeping the wood off the ground. Also they mention that plastic does not last very long in full sunlight.
High quality UV-resistant plastic can be bought around here, as there are many professional greenhouses in this area. I like their simple but open design, and large area for air circulation. In places that get a lot of snow (like here) they would need more 'roof' support though.
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maple1
Minister of Fire
Yes, I have mentioned it a few times and usually I am ignored or branded a heretic!
I have used one successfully to season Oak from the mid 50's to just under 20 percent in 4 months.
Mine is much simpler, I use clear plastic and scrap wood to make a frame that is attached to the wood I am looking to season. Cost is about $20 for 2 cord(plastic cost) but I can use the plastic a few times I think. I am getting ready to cover the second two cords for next year. I think with this method I will not have to keep more than one year ahead at any time.
Pictures might end the ignoring.
"Wood will dry even in freezing temps"
Yes it will but it is much slower then warmer temps, two kinds of water in wood, bound and free and one of them (have to look it up) doesn't do anything below 32 degrees, a kiln works quicker because the high temps drive the moisture out of the wood and the air movement takes the moisture away from the surface of the wood.
Yes it will but it is much slower then warmer temps, two kinds of water in wood, bound and free and one of them (have to look it up) doesn't do anything below 32 degrees, a kiln works quicker because the high temps drive the moisture out of the wood and the air movement takes the moisture away from the surface of the wood.
NortheastAl
Minister of Fire
Augie, I think you are difinitely on to something that works. Try it one more time, but leave one stack outside the kiln as a comparison to the kiln enclosed stack. Then report the results. I too want to dry my wood without having to keep three years around, if possible. The 5+ cord that I have now are topping out much of my usable space. I need about 9 cord to make the three year goal, and if I could cute that number back by using a kiln, then I would be happy.Yes, I have mentioned it a few times and usually I am ignored or branded a heretic!
I have used one successfully to season Oak from the mid 50's to just under 20 percent in 4 months.
Mine is much simpler, I use clear plastic and scrap wood to make a frame that is attached to the wood I am looking to season. Cost is about $20 for 2 cord(plastic cost) but I can use the plastic a few times I think. I am getting ready to cover the second two cords for next year. I think with this method I will not have to keep more than one year ahead at any time.
Craig S.
Burning Hunk
Could even take this one step further, and build a DIY heliostat to keep the sunlight on the kiln for longer periods of time.
MrWhoopee
Minister of Fire
I think the word you're looking for is sublimation:
"Sublimation is the transition of a substance directly from the solid to the gas phase without passing through an intermediate liquid phase"
Evisceration is an entirely unrelated process:
"To remove the entrails of; disembowel".
Sublimation is more popularly known as freeze-drying or freezer burn, depending on whether it was intentional or not.
It is possible for laundry to dry on the line even though temperatures are below freezing. However, it is a slow process and, as the object becomes thicker, the movement of moisture slows even more. While winter camping at temps well below freezing, I found that thin nylon items will dry very nicely overnight, leather and wool items will not. I doubt firewood will dry very much at temps below freezing, at least within a period of time that would be helpful.
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