[HN Gopher] A Solar Kiln to dry wood. Overview, design and build...
___________________________________________________________________
A Solar Kiln to dry wood. Overview, design and build (2019)
Author : animal_spirits
Score : 69 points
Date : 2023-02-04 17:26 UTC (5 hours ago)
(HTM) web link (www.adrianpreda.com)
(TXT) w3m dump (www.adrianpreda.com)
| pard68 wrote:
| I've been contemplating a solar kiln to dry my split logs we use
| to heat the house. Our stove is extremely efficient and burns
| cleaner than many traditional furnaces. But this all comes at the
| trade off of requiring very seasoned -- dry -- wood. My zero tech
| solution requires chopping wood for two years in advanced. Not a
| big deal, having two years of fuel on hand is a very nice
| feeling. But it does mean moving wood around a lot. I'd be nice
| to just kiln dry my wood and then know that all the logs I have
| are stove ready.
| mahogany wrote:
| FYI - if you don't have a lot of time, you can get away with a
| much simpler solar kiln than the one in this article, which is
| still a huge improvement over the natural seasoning process. I
| highly recommend it with a newer-style wood stove that prefers
| very dry wood.
|
| We built one last year that was essentially only the frame of
| this design (but less sturdy), and wrapped it with clear
| plastic sheeting. Super scrappy, built from 2x3s on top of a
| pallet. No plywood sheathing (although we did put bubble wrap
| around the walls), not even painted black. I eventually put an
| old computer fan at the top of it to blow outward, but
| originally it didn't even have airflow. It took oak splits with
| ~30% moisture content down to <20% in a matter of weeks. That
| wood burns hot!
| voisin wrote:
| A neighbour nearby has pallets on the ground ringed with wire
| fencing. After he splits the wood, he throws it haphazardly
| into the cage and then tarps the top. It sits like that for a
| full year before he stacks it in the queue for winter burning.
|
| Not sure how that compares to your process, but it seems about
| as efficient as possible in terms of moving wood around and I
| think it would be a lot less work than a solar kiln.
| pard68 wrote:
| I use pallets too. They're great, I put the kids to work and
| they stack it as I split. Then I shuffle the pallets around.
| They all sit in a shed, but I have to rearrange that them in
| the shed since the driest is at the back. My thought is if I
| could make a kiln that'd hold two or three pallets of wood (a
| year's worth) than every pallet that goes into the shed would
| be stove-ready and I wouldn't need to shuffle them around.
| CrazyStat wrote:
| How hard would it be to put a door in the other side of the
| shed so you can take wood directly out of the "back"
| without shuffling?
|
| One year you fill one half and take wood out the other
| half, the next year you switch.
| baq wrote:
| People build sheds with removable walls for that and
| better airflow.
| intrepidhero wrote:
| I like to say wood stoves heat you 3 times. Once when you spilt
| the wood, once when you stack it and once when you burn it.
| baq wrote:
| Get wood in early spring at most, felled in winter, if you get
| it chopped while it's still cold it'll be sub 20% moisture by
| fall by just sitting in the sun and wind. The trick is that it
| starts relatively dry.
| debacle wrote:
| What this guy said. You drop a tree before the sap starts
| running it'll be mostly dry.
| jonstewart wrote:
| The previous owner of my house (in rural Wisconsin) built some
| simple-but-effective wood sheds. They're old corn crib roofs,
| held up on 4x4 posts. Since they're not walled in you can
| access wood from any side (no need to move stacks), there's
| plenty of airflow, and the roofs keep out the rain and snow. I
| may put up some chicken wire fencing between some of the posts
| to keep dry leaves from blowing in.
|
| Of course, their appearance is... rustic.
| jdhn wrote:
| How well would this work in a hot, humid environment? He mentions
| that having a vent at the bottom is essential for getting cooler
| air in which makes sense, but I live in a place where it's also
| very humid.
| mattficke wrote:
| Humidity affects the final equilibrium moisture content [0] of
| wood, but even at 100% relative humidity it'll eventually
| stabilize at around 25-30% MC (green wood is usually >60% MC,
| for reference). Humidity averages around 65% in the areas of
| the US where most of the timber trees grow, at that humidity
| EMC will be around 12-15%.
|
| [0]
| https://en.m.wikipedia.org/wiki/Equilibrium_moisture_content
| refuse wrote:
| This reminds me of a firewood seasoning method I saw in (IIRC)
| Dudley Cook's "The Ax Book", except you pile up your split
| firewood in concentric circles around a stove pipe with holes
| drilled all around and along it's length. When the wood is
| stacked to about breast height, you cover it with
| shingles/plywood/plastic and put a vent that's been painted black
| on top of the stove pipe. You end up with air constantly
| circulating past the wood and significantly reducing seasoning
| time.
|
| (note, if you try this, make sure to put it on top of some
| branches so your firewood isn't contacting the ground)
| blamazon wrote:
| In Germany a similar but more traditional thing (bark-y wood
| pieces usually used for the roof, no stove pipe, instead a
| loosely/chaotically packed core for airflow) is called a Holz
| Hausen: [1]
|
| https://www.logsplittersdirect.com/stories/1202-How-to-Age-Y...
|
| [1]: (Literally: 'Round House')
| sgoschi wrote:
| I think 'Holz Hausen' might be an American word [1], as I've
| never heard it before. It'd also roughly translate to 'wooden
| house'.
|
| Over here we call it 'Holzmiete' [2], which translates to
| 'wood pay/wages'.
|
| Fun fact: haystacks follow the same principle! [3]
|
| [1] https://en.wikipedia.org/wiki/Firewood#Storing [2]
| https://de.wikipedia.org/wiki/Holzmiete [3]
| https://en.wikipedia.org/wiki/Hay#Stacks
| gerikson wrote:
| Link is not available.
|
| Doesn't Holz Hausen translate as "House for wood"?
| blamazon wrote:
| Seems likely! I don't know German at all. I just saw that
| when I websearched it, I actually saw these in Austria
| years ago.
| [deleted]
| blamazon wrote:
| I saw the finished solar kiln photo and thought "holy crap, they
| did an amazing job, that looks so much better than if I did it!"
| then I navigated around the site and realized they are a very
| skilled woodworker. They have a nice YouTube channel:
|
| https://youtube.com/@AdrianPreda
| dv_dt wrote:
| The comment on the cyclic nature of the solar kiln being better
| vs cracking than industrial process of just heating until done
| was interesting.
| oezi wrote:
| I didn't get why he would only pull in fresh air once per day.
| Once the humidity gets too high even the high temperatures will
| lead to less and less evaporation, right?
|
| I would have expected that it would be best to bring in a light
| constant flow of dry air while maintaining a certain
| temperature.
| Etheryte wrote:
| That last bit is the devil in the details, you won't get
| anywhere near the temperatures shown in the followup post if
| you keep even a little bit of airflow going.
| justsomehnguy wrote:
| Be sure to check out the second part, with _data_ :
| https://www.adrianpreda.com/blog/solar-kiln-run
|
| Also it make me wonder if a Peltier unit could provide enough
| power for the fan here.
|
| Of course you can slap a solar panel there (even those camping
| ones should work, I think) but IMO it's a bit cbeating.
___________________________________________________________________
(page generated 2023-02-04 23:00 UTC)