gyrfalcon said:
Here's the thread on Battenkiller's indoor wood-drying experiment. Definitely worth a read to see what he did and how it worked.
Ack! Thanks for reminding me... I never got around to finishing up the final (6 week) results. I better go back and finalize it sometime in the next couple days, some of the most interesting observations came from analyzing the data more carefully.
Yes, 60% MC down to 20% MC in three weeks.
But... two of those weeks were needed to go from 30% down to 20%. That means if you're starting with wood that is 30% and you want it to get to 20%, a few days in the stove room just won't do it. After the initial rapid dumping of free water in the wood, every day left the wood with about 97% of the water that it had the day before. That's the nature of exponential decay, it slows down practically to a standstill after a while.
And if you recall, my stove room temps were in the upper 80s, outside temps were extremely cold (lowering the absolute moisture content of the air that was infiltrating into the house), fans were employed (actually, not on the test split itself, but that one has complete open access to room air). In short, the perfect drying conditions were present in order to get that result.
Now that shoulder season is nearly upon us, it will be impossible to create the extremely low RH inside the home that was in large part responsible for the rapid drying. Warmer outside temps mean higher absolute moisture content. We won't be cranking our stoves as hard either, so the inside RH will be even higher (mine is up in the 40% RH range now), so drying will be substantially slower. That's just the sad facts, there is only a short window of opportunity to pull this off successfully, and that window is closing fast. I brought in the last load of black birch about two weeks ago, and that's it for me for the season. Long experience has shown me that there is a very poor return on my time investment at this point in the season.
So what's a poor burner to do? Well, about two weeks ago I decided to try to heat this place for an entire day using nothing but freshly cut hardwood. The results were quite impressive. Plenty of heat, zero smoke, the cleanest, whitest interior stove surfaces I've ever seen the following morning. If I can do that with fresh cut wood (around 60% MC), you should be able to get stellar results with wood that was cut and stacked back in the fall. Some simple observations, if they might help:
- Bring some wood in anyway, and put fans on it. It will certainly help if you can leave it alone for about a week. Split it small and stack it loosely. Even if the inside doesn't have enough time to dry out, the outer surfaces will get quite dry, allowing for much easier ignition... and that's 90% of the battle right there.
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Build the fire slowly and wait three times as long as usual before you even think about closing down the air. If the fire goes out (no active flame), you will get a slow, smoldering burn and you will get poor heat output from the stove and a concomitant drop in flue temps... and the dreaded creosote will start to accumulate in the flue, possibly at an alarming rate.
- Reload the stove while there is still a raging coal bed. You won't get uncontrollable secondaries since the wood will be outgassing slower, and you will need all of the heat you can muster to get those secondaries to light. Wait too long and you need to start all over again with small stuff. Reload in stages. A few small splits... wait 5 minutes or so until the new wood is fully involved, then add a few more splits, and keep doing the same until the box is fairly full. Rush it and you won't get it to ignite properly.
- If you have a small supply of dry wood, don't waste it by mixing it in with the load, you will run out and then you are screwed. Use the dry stuff to get the stove hot in the beginning, then when it is real hot you can feed in the less seasoned wood. It will burn fine as long as you have a very active fire going already. Just don't add too much at once, it will cause internal temps to drop and your flame will go out. I can't emphasize enough the importance of keeping very active flames when burning unseasoned wood.
- At all times, you will need about 25% more air than you normally do. Give the fire what it needs to maintain high temps and active flame, but don't open the air all the way (except maybe at the beginning). That can actually cool the firebox down and... well, you get the picture.
If you do everything perfectly you will get near maximum heat output from your stove, but there is no getting around a significant loss in efficiency. You will burn about 10% more wood by volume than you would to get the same heat from fully seasoned wood. Some of the heat loss will be in the unrecoverable heat of evaporation of the excess water, some will be in the increased heat loss up the flue. But you
will stay warm, and it will be cheaper than paying the oil man. All in all, a major PITA, but you
can burn the stuff cleanly and with good heat output if you pay careful attention to the details.
BTW Gyrfalcon, the BK test split was placed back outside in a dry place after the six weeks was up. Will it continue to dry out there? Not bloody likely. It has already
gained about an ounce and a half in weight as it starts the long, slow process of reaching EMC with the outside air. I will report back some time in the summer, at which time I expect it to be up around 14% MC.... about 3% higher than the 11.06% MC it had when I put it out there.