Warning: long post. Hi all, I have been lurking and reading posts for a while now. Finally have something to contribute I feel might be interesting to most of you. Due to a variety of factors, I do not have enough dry wood for this upcoming winter 22/23. This past winter was my second season heating full time with wood and I have used up all but two face cords of dry wood (I use around 4 full cords). Add to the situation that I chronically don’t have enough time to cut ahead and most of my prime heating season wood available being red oak, I knew I had to take a different approach for seasoning this year. I looked up various posts on this site and others about solar kilns and decided to build one. The primary inspiration was Uncle Auggie’s design, but I wanted something more permanent than his method of wrapping every season. I decided to go with essentially a lean-to shed wrapped in greenhouse solar protected fabric. The shed is 11’x11’x(6’ short side and 9’ tall side). I cut my wood at 18” long so I should be able to fit 6 rows of wood 11’ long by at least 6’ tall. Approximately 5 cords of wood total. I started building in late March and finally got it done 6/3/22. The entire thing is wrapped in greenhouse fabric with no intentional vents. The floor has a few hundred small holes poked in it to let the accumulated condensation escape. I also added 4 more small holes on the underside of the roof (short side) because of all the condensation running along the underside of the roof and collecting there - see the pictures. Probably around a gallon of water was in there today before I poked the holes. I also decided to a small experiment with a small cottonwood I cut down to get more sunlight on the kiln. There are six unsplit pieces, (2 control - uncovered, off the ground, 2 kiln pieces, and 2 tarped- wrapped in layers of plastic with weep holes at the bottom elevated off the ground). I took starting weights for each and my plan is to measure the weight every month or so this summer and keep this thread updated. C1: 5.4 lbs C2: 5.4 lbs K1: 7.6 lbs K2: 7.6 lbs T1: 9.0 lbs T2: 7.8 lbs Here are some numbers over the previous 2 days (this is with about 1.5 cords loaded in it): 6/6/22 @1300:83 outside, partial sun, 107 inside, 30% rh @1715: 81 outside, partial sun, 89 inside, 65% rh 6/7/22 @1125: 68 outside, partial sun, 86 inside, 65% rh @1300: 68 outside, partial sun, 104 inside, 55% rh I won’t be able to consistently check temperatures at the same time each day or indeed every day, but will try and get a few per week. Oh, and the kiln will get full sun from sunup to around 1500 or so and then only partial sun after 1500 (due to my tree line). I could put more information in but this post is already getting long. Let me know any comments/questions!
Looks good Spitfire0905 Looking forward to your results. I have thought about a solar kiln off and on.
Awesome! Why not have any vents? All the reading I have done, they always say gotta have 'em. I plan on doing 2-4 cords over the next two weeks. Stacked on pallets. Shrink wrap plus plastic.
Hey, that is really cool! Welcome formally here too..... I was figuring out Sunday, that a cord of unseasoned red oak, at 4888#, would loose 170G of water, loosing over half a ton of weight. I once saw the greenhouse style kiln, looked like a Quonset hut. Id love to do that, but it would be a real eyesore to neighbors here....to stuff 20ish cord into anyway. Even to speed dry a few cords though, is a tantalizing prospect. Even now, our oldest wood will be just under 2 years old by this fall. You've got me thinking.....and, last summer here in the Northeast, was the wettest in my memory, so not a lotta drying happened here. I think the real proof will be measured in putting up green wood in june, and seeing it down to 20%m.c. by September (or whenever) with your setup. Looking forward to your results!! Sirchopsalot.
Not to spend your money I think if you invested in the right weather station that streams data to the right application you could trend it 24 /7. Same might be true of a moisture meter, and I suggest you get 3. 6 would be silly. Welcome aboard and look forward to what you find. Nice job on the shed
Welcome to the club! Excellent 1st post! Now figure out how best to get some air circulation in there.
Very interesting Spitfire0905 I would do that in a heartbeat if only it could last in the weather from year to year. I'll be watching the results on this thread! ...........and welcome aboard!
You need vents.. The idea is not only to heat the wood and surrounding air, but also remove moisture.. You are trapping most of it… Nice build though.. Go to hearth.com and checkout firewood kiln posts/threads by “woodsplitter67”..
But........too many vents and you loose the high temps inside. It's a trade off. As long as the moisture in on the plastic and able to weep out, it's not inside the wood chunks.
Welcome Spitfire0905 . Nice build. Expect this topic to get a little heated, pun intended. We've lost members in the past who got overly spirited about it. Hopefully everyone remains polite with their opinions this time. Some folks don't agree with the lack of ventilation. IMO- If water is leaving the closed system (through the weep holes) and no water is entering, it is getting dryer. Keep us posted on the results. Good luck.
Great build and nicely done. Be interesting to see how it works out. What species will you be drying Spitfire0905? Great first post btw! Glad to have you join the insanity...uh i mean fun!
The guy i got my fence posts off of for the garden did that. They are auto/temp controled, but he can open/close them from his fone. He's an electronics genius. The ropes pull the vents open. Servo motor/lift cylinder connected to ropes
Welcome to the forum Spitfire0905. Some good ideas there and I wish you good luck. I would also be interested in the total cost of building this.
It will be interesting to watch the progress of this wood and to see if you need to add venting or not.
Interesting, Spitfire0905 . I hope the plastic stands up to the wind/weather. You've probably already seen this solar kiln study, but just in case... https://www.fs.fed.us/pnw/pubs/pnw_rn450.pdf
Probably too many CFM...there is a delicate balance between getting enough heat built up, and venting moisture
