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Solar kiln

Post in 'The Wood Shed' started by DTrain, Jan 22, 2013.

  1. DTrain

    DTrain Member

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  2. bmblank

    bmblank Minister of Fire

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    My dad and his friend built a solar kiln for my hardwood flooring (red oak, from my dads land). Got it down between 6 and 9%. I was considering building my woodshed in a somewhat similar fashion. I was sorta thinking something in the passive solar heat kinda way. But no experience in it yet.
  3. DTrain

    DTrain Member

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    I have to build a wood shed this summer. I think I might give'r a go.
  4. bmblank

    bmblank Minister of Fire

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    Take plenty of pics. I'll be building one shortly also.
  5. bmblank

    bmblank Minister of Fire

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    A shed, not necessarily a kiln.
  6. lukem

    lukem Minister of Fire

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    My dad has a solar kiln. Basically a shed roofed and sided with clear plastic. Works good for boards. Not sure about cord wood.
  7. swagler85

    swagler85 Minister of Fire

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    DT if you buy the app tapatalk you can post pics. I put it off for a long time but tried it and I love the app. Well worth the small expense and it works with most all forums.
  8. renewablejohn

    renewablejohn Member

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    We have commercial solar kilns drying upto 250 m3 of split logs at a time. Normally takes 3-6 moths to get logs below 20% moisture content.
    Blue2ndaries, ScotO and Dune like this.
  9. renewablejohn

    renewablejohn Member

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    We have commercial solar kilns drying upto 250 m3 of split logs at a time. Normally takes 3-6 months to get logs below 20% moisture content.
  10. DTrain

    DTrain Member

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    What do you think if was cut and split to stove size sticks? Less time I would think.
  11. Jon1270

    Jon1270 Minister of Fire

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    I doubt a home solar kiln for firewood would be a good use of resources. It would speed things up, but also require extra handling of the wood since it's unlikely to be big enough to hold your whole winter's supply. Might be nice for the first year or two if you have no other way to get dry wood, but after that it would be pointless; by then you could have achieved the same thing by just letting it dry out in the sun and wind. So to make sense I think it would need to pay for itself -- the engineering time, the materials, the labor -- in the first 2 years. That seems improbable.
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  12. Dune

    Dune Minister of Fire

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    A solar firewood kiln can be as simple as a framework with clear plastic stretched over it. The key is that the plastic not touch the wood at any point and that the plastic not reach to the ground.
    ScotO likes this.
  13. Jon1270

    Jon1270 Minister of Fire

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    Would be far less effective than the sort of kiln linked to upthread, but certainly cheaper and it might help a bit. I doubt it would make a dramatic difference in drying time.

    My familiarity with wood drying is more oriented towards lumber rather than firewood, but the general problem is that any enclosure reduces ventilation to some degree, so an effective kiln has to balance ventilation and temperature gain against each other so that the relative humidity ends up lower rather than higher. Some designs work, and some don't.
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  14. Dune

    Dune Minister of Fire

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    The idea is to remove moisture, not ventilate. The heat created by the tent caused moisture to vaporize, then condense on the plastic and drip away.
    These simple kilns, promoted by Mother Earth News since the seventies have been known to reduce seasoning time to as little as five months.
    Applesister, DTrain and ScotO like this.
  15. Jon1270

    Jon1270 Minister of Fire

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    Ah, letting moisture fall away as liquid rather than vapor. Neat idea. Anyone have a link to one of the Mother Earth news articles on this?
  16. ScotO

    ScotO Guest

    I plan on building my shed similar to this. I'll still season it two years uncovered, and load I into the "shiln" (kiln/shed) in Tue summer prior to using it. That should make it absolutely PRIMO for the stoves. Hoping to attempt the build this summer. Don't worry, I'll take plenty of pics and document the whole project.
  17. gerry100

    gerry100 Minister of Fire

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    I've got a basic open front shed with a sloped metal roof but...

    If I were doing it over again I might consider replacing the metal with translucent fiber glass panels expecting that it would get much hotter in the summer. the open front may negate much of the advantage however.
  18. Augie

    Augie Feeling the Heat

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    Here is a link to an article from Cornell summarizing a study of this very fact. They say that in 3 months 8inch splits and rounds are below 20% moisture content. I will probably tent up 4 full cords this summer in an attempt to speed the process. As Im a new burner I am trying to build up my supply of seasoned wood. By tenting 4 cords I should have enough seasoned for the following winter. Of the 4 I was thinking of tenting some oak in an attempt to shorten the seasoning from 3 years to 2 maybe and then Ill be set for the future.

    Looks pretty easy Air in from the bottom and a small vent at the top. priced it out based on my situation looks like it will cost $40 for the four cords for cheap plastic and I have enough scrap lumber to fab up the frame. $40 for 4 seasoned full cord is pretty cheap IMHO.
    ScotO likes this.
  19. DTrain

    DTrain Member

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    Nice, I like to see the ideas flowing! Just when I thought Jon1270 had whizzed in my corn flakes, I see the book is not closed on this idea. Thanks for adding your two cents every one!

    That would be a sight seeing that water condense. Just like those survival shows to get fresh water in the desert. Would the surface of the plastic require a point of condensation to aid in condensing?
    ScotO likes this.
  20. Augie

    Augie Feeling the Heat

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    Nope just the high peak to collect the moisture and space for it to fall but not touch the wood. I have seen people using kilns for drying wood utilizing solar attic vent fans to move air. this is a careful balance though. you want temps high enough to keep moisture moving out of the wood and enough air movement to clear the moist air. Im guessing that you can get most species dry in a summer,(IE Maple, ASh, Pine, Beech, Elm, Walnut, Aspen, Dogwood) but im hesitant to call oak until I try it.
    ScotO and Dune like this.
  21. Jon1270

    Jon1270 Minister of Fire

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    Aww, I would never do that. I might try to dissuade you from whizzing in your own corn flakes.

    Thanks for the link to that Cornell document, Augie. It's a shame Mr.(?) Stone didn't set up a control group for his test.
    DTrain likes this.
  22. Jon1270

    Jon1270 Minister of Fire

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    On reflection, it could be that kilns meant for drying long pieces of lumber down to 6-8% MC without creating defects like case hardening and checking need to maintain some combination of higher / more consistent / more controllable temperatures and humidity levels, thus the electric fans and insulation that go into those arrangements. Firewood doesn't need to meet the same specs, so something simpler might very well suffice.

    If only such a kiln worked in the shade...
    ScotO likes this.
  23. bmblank

    bmblank Minister of Fire

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    It will work in the shade... You just need a whole lot of heat lamps pointed at it 24/7. :-D
  24. DTrain

    DTrain Member

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    Well you did a little, but I know it was coming from a good place!
  25. Jon1270

    Jon1270 Minister of Fire

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    Sorry. It was an accident.

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