I was thinking cutting the top off an IBC tote bladder-liner, flipping it over a wood pile, then mount a small fan (like ones they use on small chicken coups or sheds)on the side. Would the plastic let enough sun through to be effective? Obviously I would only be able to do about 1/4cord each time. Maybe set the pallet on some rubber roofing material so not to suck ground moisture through.
My thought is that it's too opaque, would not let in enough light. I'd cover it with clear wrap or sheeting or both. My current solar kiln is a wood stack wrapped in plastic film and the top covered with plastic sheeting, 3mil (what I had on hand... 6mil might be better), and air vents cut in each end plus apex in middle. I have been thinking that a tote would work great. If I were to do it, I would crown the stack (like I did my solar kiln stack) such that there is a crown of splits. Done in a tote, you could have a face cord in there, 1/3 of a cord. Hopefully, my (first) solar kiln actually dries the wood. People online say that it will. It gets 130 to 140 degrees F in there. Will know come the fall. EDIT: BTW... I would like to know the answer to your question, as well, as my brother lost a steel hoop / plastic fabric structure due to wind. It looks kinda like a greenhouse or a car garage except the fabric is a bit opaque and I have wondered the same about light getting in. I could build a structure with wood and use that fabric. His steel hoop structure is bent/crushed such that it is trash material now. If I could use that, I could probably put several cords in there. It's fabric cover went all the way to the ground.
Interesting concept. I'd say you'd lose some volume as the inside dimensions of the bladder would be less than that of the tote. I wrapped 2 275 gallon totes yesterday with 4 mil sheeting to test that method. I already stack in totes so wrapping didn't add much to the current process. I put a 1/2 bladder top on one (to shed rain) and nothing on the other. Could be worth trying the bladder method to see what results you get. Good luck!
You need air in from the bottom up through stack exhaust out the top. so bottom off ( air intake), sides stay ,top off for filling, then place top back on with a weight of some sort to keep it there open fill cap on top as this is your exhaust port - will work something like a regulator no fan needed. Just natural heat rise. depending on the Ibc tote some have drain holes in the bottom some just have some drain channels so placing on something to elevate off ground a bit more than the gap it already has helps a bit vs vegetation blocking air. think like a tent gets hot in there . translucent will be fine.
Try it. weight some splits, marked so they can be reweighed to track any progress. When used to store water, The bladders have a propensity to grow algae in the sun, which need light .......
If you got the stuff to do it.... Sure why not. It isn't going to not dry the wood... Interested to see if it make a difference.
I was reading another firewood kiln thread on another site and this well known and long time member has some pretty in depth data from doing kilns for years now...one of the things mentioned recently was that in his climate (Alaska) if he waited too long to load the wood the warmer spring temps left the wood sit in the kiln "wet" too long and he got significant mold. Loading green wood during real cold weather was fine, and loading green wood in our warmer (on average) climate seems fine too, as long as the daytime temps can get pretty hot right from the get go...but it sounds like if you load green wood in weather where the kiln temp can only get a little "warmish" during the daytime, mold city.
That was why I was going to put a small fan on it. Hopefully it will keep moisture to a minimum level so no mold
We're plenty hot enough now to not need it though...my guess (swag) would be that if you can get the internal daytime temps over 100* (maybe 80-90?) it probably won't mold...and weather like we have now, 140* should be no problem.
My point was algae would grow with enough light transmission and enough light transmission should allow for heat build up, but there's that problem too I guess. Still think it's worth a shot if you got the stuff hanging around.
I don't think you need direct sunlight for the kiln to dry wood. Sunlight hitting the wood will help directly heat the wood. If the kiln gets enough sun light to heat the air within it then it should work. A steel land sea container will get the air inside above 140f when exposed to direct sun light. Having a window or clear plastic surface just lets the infrared heat the interior surfaces instead of just the exterior which then relies on convection and conduct to heat the wood. Yes, a window should improve kiln efficiency as long as it doesn't block IR energy. If you were to use modern house windows in a solar kiln they may block IR to minimize solar gain in an effort to keep houses cooler in the summer.... depending on region windows were built for. I believe the biggest difference is air exchange. You want to heat the air and interior of the kiln so the relative humidity drops. The moisture in the wood will want to escape and get the wood and air moisture to some equilibrium. As the humidity rises it will approach a dew point and start to condensate on the cooler surfaces of the kiln...dark corners or the middle of the wood pile. You need enough air flow to exhaust the hot, high humidity air and pull in cool, dryer air. But you don't want high exchange rates or the new air won't heat up and become saturated with moisture. Too high of air flow and the kiln would effectively be the same as leaving the wood outside. High temperature help increase the quantity of water the air can hold and increases the rate of which water will evaporate. Heating the wood pile up makes it a big thermal battery in a way so the drying process can continue after the sun goes down. And if enough thermal mass is present in the kiln it helps jumpstart, maintain, the process the next morning. Unintentionally, I have turned my trucks high top camper shell into a solar kiln for firewood. I'll cut the wood and load it into the truck. I don't always get to unload the wood right away. Parking the truck in an open parking lot will really heat up the wood and topper shell. If I don't crack the windows a bit I will get severe condition and rust on my chainsaw files in less than a day. I can notice a difference in log weight in just a short week of baking in my truck bed kiln.
Direct sun on the wood is not absolutely necessary...if it was then how does your attic get up to 140*?
I think the thicker the material (IBC liner for example) the less chance and/or the longer it takes for heat transfer. Would you be further ahead by just removing the liners and wrapping the ibc tote with plastic? If you are going to try using the liners for the kiln, showing results would be the best answer to your question. Each of these solar kiln threads have resulted in "better" ideas that haven't been proved.....adding fans, vents, blocking the bottoms, cutting in larger vent holes, etc. etc. Good luck!
