Drying wood indoors - heated floor thoughts?

[jnewman67]

I'm looking to dry my firewood a little more consistently - my wife is tired of the rows of wood covered with silver tarps, so I have some leeway to build a sizable wood shed. I'm thinking of adding a DIY heated floor (solar thermal heat) and wondered if anyone thought that method of "baking" the wood would work well. It'll be enclosed, can be as over-engineered as I like, can operate for free year-round, and will be both pleasant on the eyes and functional. I'm thinking 12x12 or 16x16 in size, enough to store 3-4 years of wood @ 2+ cords a year used.
I'm thinking of creating a heatsink under the floor heated by warm air to generate the heat for the space above it. it'll never be high-temp like direct sunlight might be, but I think it'll speed up the moisture removal, and help the wood dry slowly and evenly, and it should keep all the wood relatively the same moisture content. If i got fancy, i could even build in cutoff switches when the humidity in there dropped below a certain level (we'll call that a Phase 2 upgrade) so I don't overdry it.
I like the simplicity of clear hoop structures, but those will become greenhouses the moment she sees those, and the shed seems like a more sightly, longterm, durable solution.
for the record, i'm not looking for kiln dried - just a lower moisture content so I get quick starts in the stove without a lot of smoke and condensation.
And no, I haven't checked to see what my MC is currently. Based on what I put in the stove this afternoon, I should've rung it out first, so pretty sure that 2+ year pile i'm pulling from could've been a bit drier still.
There are a LOT of details I could add, but generally looking for thoughts on how well the "floor heat" idea would work. adequate ventilation is assumed.
Thanks.

 

[ClintonH]

I think your biggest hurdle is sufficient thermal mass to drive out water from the large mass of the firewood (and its consequential cost). I think the bottom-up heat will be effective at moving water bound in firewood. As for the solar - are you thinking a solar-heated water system with in-floor heat in some fashion? I'm just struggling with how the floor gets heated and eventually heats the wood to move moisture.

 

[EbS-P]

Spend you time and money building bigger/better shed and or gathering more wood. If IBC totes as solar kilns can speed up drying by 12 months. It’s the dry air moving through the stack that dries wood. Look up how to build a holthouzen (spelling?).

I can almost guarantee that another 12 months of drying in a shed will make more difference than any heated floor. Build a 4 bay shed for a 3 year rotation. Burning, 2 years, 1 year, and filling with green wood as you split it.

 

[stoveliker]

I have Just an open shed with 3 bays. Burn 1 bay a year.
Roof but no walls. Roof overhangs a lot, 2 ft in front, to avoid rain hitting stacks.

Dry for three years and you will notice a large difference in performance.

 

[jnewman67]

thanks for the responses.

@EbS-P: you referenced a Holz Hausen ( https://www.firewood-for-life.com/holz-hausen.html )
While a cleaner looking wood pile, I think i'll still be met with the same look of "that's still a tarp"
The 4-bay rotation you mentioned is what I was already leaning towards, but figured with the added heat, I could make it 3-bay. I was just supplementing it with some heat.

@ClintonH: solar thermal collectors come in 2 varieties - air and water based. I was going to use the air based - nothing to worry about freezing. you've seen the black boxes people attach to the sides/roofs of their houses - that's them. a small solar powered computer case fan moves air through channels in the box, and a sheet of black aluminum in the box collects the heat from the sun and warms the air.

The heat sink was going to be something along the lines of a layer of cinder blocks/bricks arranged under the floor in a pattern such that the air would flow back/forth under the floor, heating the bricks, which would then radiate up. the air coming out the other end of the maze would head back to the solar collector to get warmed back up. i was planning on building the collectors between the joists on the wall facing south. could put them on the roof as well if that was deem more effective, summer vs winter drying.

the heat sink could also be 3" corregated tubing snaked back and forth under the floor, covered in sand (with/without a layer of cement patio blocks over it). Less air leakage, better air flow, more contained system. both versions would be surrounded by foiled foam insulation to keep the heat in.

no idea how much heat would be generated, but i know the unit my grandparents had in the 80s was pretty effective at heating their living room.

 

[jnewman67]

I should point out how I currently store wood.

4 rows, 4 pallets each row, 16" length, stacked 3 wide on each row, 4-5' high. Tarps cover the top and overhang the sides about 6-8".

they get tarped as soon as I'm done stacking the wood. the row i'm working on (last one) is over 2 years old - didn't cut any wood last year. i intentionally ran down to the end of the piles this year in preparation for building the shed.

 

[Eman85]

Buy black tarps or brown ones, expend your energy and time cutting and splitting.

 

[EbS-P]

why don’t you use this concept for a small green house. I just find all the effort put into this really won’t dry it much faster. It’s basically a solar kiln in a shed. You have to be thoughtful.

One of the members here in N.C. has a fully enclosed wood shed that gets full summer sun. And get hard woods dry very quickly.

That’s an option if you have a good location

 

[stoveliker]

I would not heat blocks on the ground; half the heat will end up in the soil.
Heat the air and blow it under the stacks, then have a top vent in the shed. This'll get warmish air and flow. That is what dries wood.

Or just have a pv panel that runs a few fans. Heat doesn't help much if the moisture can't disappear, so make air flow and it'll help.

 

[EbS-P]

Look up plans for solar lumber kilns.

 

[jnewman67]

Again, thanks for the responses

I'll ponder, lots to review.

Thanks.

 

[Woodsplitter67]

Again, thanks for the responses

I'll ponder, lots to review.

Thanks.

I think your waaayyy over thinking this. 1 cord of harwoods is aroun 3K Lbs so any kind of mat will need alot of energy to heat up that much wood, let alone 4Xs that amount. Your not interested in a kiln which will achieve what your looking for not to mention that a greenhouse is the same idea as a kiln. Your talking a ton of labor moving the wood around.

Id seriously look into a nice woodshed. One that will hold 6 cords and your wood will be nice and dry WITH OUT trying to heat it up. I have 4 holding a total of 14 cords CSS and my wood is normally about 16%MC. It gets stacked and doesn't get touched again until its needed. No tarps no babysitting.

Doing a shed that is vented all the way around with a large roof overhang and the front facing the summer prevailing winds will assure no rain or moisture gets on the wood and you receive the maximum drying of your wood

 

[ScottLewis]

My woodshed is 12 x 8. It sets at least 16 inches above the ground. It has no ventilation at all. It sets in direct sunlight all day long. It works on the principle that water vapor will pass through non stained and non painted wood. I can put fresh cut green chestnut oak in my woodshed in February, and by November it is 17 percent moisture.