Wood Drying Methods

I don’t see a category for wood drying on here. But it might make sense for there to be one. I think the topic is worth having a serious discussion about.
Here is a simple idea for drying a batch of wood that I’ve been thinking about.
Rindert

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Here’s a short video that shows my drying method for wood CHIPS (not chunks):

Later on I learned to do a rough job of sorting on-site where I found the chips. That makes drying go a lot faster.

Pete Stanaitis

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Farmers dry grain in big silos using hot air forced up through the bottom of the vessel. Your design looks pretty similar to those grain dryers albeit on a smaller scale. I’m pretty sure the farming version uses NG or propane but again, same idea.

You could the run the wood furnace’s inflow air past the hot chimney for some extra heating efficiency like a condensing home gas heater. That would require some method for diverting any water vapor that condenses though. Maybe not worth it.

I had ideas for a solar dryer where extra efficiency would be important. A counterflow heat exchanger would dump the water vapor coming off the wood but recycle most of the sensible heat into the inflow air with a heat top up from the solar. There is no pressure on the heat exchanger so it can be a pretty cheap/flimsy unit. I was thinking DIY with heavy duty aluminum foil and lots of layers.

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I thought about that. But the whole thing about Rocket Mass Heaters is that they are efficient, cheap and easy to make. And since this one would not be heating a living space it wouldn’t need to be sealed to prevent carbon monoxide poisoning. It could be even cheaper. With experience, cost might be 50 dollars and one day of labor. Of course more permanent and or better looking things could be made by building this inside a shed & etc, etc, etc.

I’ve thought about using solar hot air panels feeding heated air into a grain dryer type structure. But people who would need this dryer the most, such as those living in Michigan’s Upper Peninsula don’t get enough sun to make a solar drying system work. Here in Colorado we have such a dry climate we actually have to water the compost pile or it soon becomes a fire hazard. It would only make sense to build a wood dryer in very wet climates.
Rindert

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While chunking the fuel it is shoveled on a trailer. I then pull the trailer under a shed. A portion of the wood spread about 6 inches deep . This portion of the wood is usually dry in about a week and will be used or bagged. More will be spread out in it’s place but may not need to dry as long because it dried some in the pile. Before all is used out of the pile it may only need to be spread a day or so to be dry enough .

I try to get the moisture down to about 20%. The chunker will fracture the wood so that it drys much faster than if the chunks were sawed .

HAVE WOOD WILL TRAVEL

IMG_1067 IMG_1068 IMG_1069

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In almost all of north America wood will dry in natural conditions. The least work and larger amounts that can dry at once are the desirable goals. Wayne’s approach is hard to beat. Jo also has a good bulk system going.

Woodmizer marketed a solar lumber kiln, and decades ago Fine Woodworking magazine featured a drying kiln which used a dehumidifier and elaborate controls. But for just drying nature and a bit of time are unbeatable.

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This works very well for firewood.

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So Bill - That’s basically what I had in mind but with a heat recovery ventilator to speed things along and achieve a bit lower moisture content.

My thinking is just that - thinking. The doers seem to prove out that simple wood drying works fine.

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I live off grid and won’t be installing any fans.
This wood shed faces East/West and the wind goes through pretty well. I put split birch and maple in here in June the other year at 40% and by October, it was down to 20%. I checked by cutting a piece in half and testing the fresh cut part. Throughout the summer, condensation built up on the inside of the plastic as it was drying. By October, no condensation.

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FWIW, I have about 6000 bd ft of lumber that has been drying for as long as about 40 years. It’s in a metal sided pole building with a dirt floor. It all stabilizes at about 16%, using my Lignomat moisture sensor. I live in west central Wisconsin.

By the way, to test wood chip and small chunk moisture, I weigh a sample, then bake it in the kitchen oven for about an hour at a time at 250°F, reweighing and rebaking until no change in weight. Then calculate water loss, etc…

Pete Stanaitis

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