Ok testing out the base version now. Ill be adding on more here later, but it is starting to get a bit cool here at night so wanted to get something built for the time being. However on my RV version I am adding a second barrel stacked with a center core heat exchanger with a force air fan. So imagine a big hole passing through this top barrel. This will also have a flex SS coil for hot water and the cook top adapter.
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The top barrel for water heating is almost like a reverse multi tube steam boiler. Pretty neat!
Edit: By reverse I mean the hot air is where the water normally goes in a steam boiler.
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Many years ago I had a barrel heater in a cabin. just one with the door kit and legs like they still sell. One night the creosote in the chimney caught fire. One of the scariest things I ever saw. The pipe was glowing almost yellow hot and you could hear the stove huffing for breath. No idea why the whole place didn’t go up in flames. I guess the flue burned out all the creosote before it reached critical mass. I’m sure yours is built to prevent that kind of event but the top barrel is a good plan. I know you are always doing R & D but what happened to the unit you built in that spaced last year? That was an excellent design.
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Yeah this stove here is probably what you needed in the cabin not a 55 gallon drum. That is way WAY to big!! Im guessing you probably had to run it to where it could hardly breath in order to be comfortable and it sooted up.
This stove here is a little more than meets the eye. This does have a floor pan designed to distribute air around the fuel and result in some charcoal production. So far it ran great last night and did not cook me out of the RV 48*F low last night.
I have a source for free slat wood so I am heating both the RV and the shop this year on this fuel versus $5.50 a 40 lb bag of pellets. I cant bring the pellet stove to market either as it is regulated. So there is as kit version already designed I have not released it to public yet. `
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I built the version with the sight glass, this version will be a bit more expensive as the sight glass and couple alone cost $50 bucks!! This has holes drilled into the couple to wash the glass and supply the upper stage combustion. It burns a lot cleaner. I started with four 3/16 holes and probably wont change it as it seems to be working good. If its running too cold you could drill them out to larger holes.
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Built the rest of the options today and giving her a test run. That heat exchanger works awesome its hardly warmed up and it is converting quite a bit of air. I wont be cold this winter that is for sure. It will also take the place of the microwave, not as fast but convenient. Not sure how effective the stove top will be on the double stack yet.
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Is the coil for heating water? We have one of those in our wood cook stove i always look forward to the stove for that reason because we can get really hot water out of the tap.
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Looking good! How much power is that thing supposed to be able to output?
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It should sustain 5 kW continuous and up to 8 to 10 kW peak output.
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Ok I had a pretty good wood harvest from the pallet manufacturer today. So in this mix I had a bit small chunks so ran this fuel through the CFK-10 kiln to get energy net percentages of the gross. This run was not so successful, but its only one of many in the future and I will continue to record and document my findings.
This run I only had a volume yield of 1/3.
Ok so my gross weight with out the weight of the can was 97.5 lbs. Average MC (out of 25 readings taken) was 23.68% does not seem to jive with the weight as this one weighed a bit more than usual.
So Gross BTU Value= 637,260 BTU
(100 - 23.68%MC = 0.76 lbs) X 97.5 gross weight = Net weight 74.1 X 8600 BTU ))
My net weight of the charcoal yield was 15.7 lbs.
Net BTU : 152,290 (15.7 X 9700 BTU pr lb )
Net percentage of the gross is 23.8% 
Some of the chunks were a bit large and square that is different than when I process the slats. I will process a barrel of slat wood and do this test again. I also plan to run the kiln in open top mode to see what way runs most efficient.
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Additional data.
Net Volume percentage of Gross = 30% net Charcoal
Net Weight percentage of Gross Weight = 16.1% net Charcoal Weight
Net BTU of Gross Potential BTU = 23.8%
Run time was 1 hour 45 minutes. (this also leads me to believe the fuel is weter as usually we can process 30 gallons in one hours time. But this could be that this more hard wood)
I did not have any pre process energy input. But this will also be factored later for runs that I have this input.
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Would a fuel drying rack above or next to the kiln help?
Perhaps forced draft would speed the burning and there production.
Any thoughts on how to add water heating to a CFK style kiln?
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Yeah all of what you are saying will benefit the process. For water simply wrap the fire tube/hopper with SS flex hose like I did with the barrel stoves.
I am later going to add a second set of barrels to stack on top of this existing kiln. So basically this is like adding the drying rack. Make it taller so the fuel has more time to dry as it is processed.
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Something else I want to try is layering in chips. The idea is to torrify them and not bring them all the way down to char. Id have no problem running them in a mixture in my machine I have successfully mixed in raw pellet fuel just dont over do it. lol
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Does the process of torrification produce flammable gasses?
If not, perhaps you could pass the exhaust gasses through the a container of chips rather than adding them to the hopper.
Basically it would be a “black oven” in wood fired oven parlance.
This could provide more control to the process, filter your exhaust, utilize the heat from your charcoal making, and allow you to swap out batches of finished chips on the fly.
Stainless steel warming ovens are often converted into smokers, they might be perfect for this.
The space between the hopper and the shroud would seem to be the hottest.
Do you have any concerns about the corrugated hose restricting the draft, or the water flashing over into steam?
Looking into torrified wood, it seems to have a dollar value beyond being fuel.
A dedicated Iwasaki styles kiln might be perfect for torrifying long lengths timber or lumber.
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Yeah if we could control this so we dont make a bunch of smoke it would work and great way to reclaim engine heat. But Ive been here before and was unsuccessful at controlling that. I would always take them too far. However now that Im playing with a kiln might try venting this into the kiln process and use it to burn off that smoke.
However I think just making a fuel dryer using exhaust heat would be better. Then just building the kiln in a double stack system I think will show big results. I know that when we ran bone dry fuel it was quite efficient, nearly all of it converted to char coal. The difference in that scenario is when Id shake the grate a lot of fuel inside would come crashing down and it would sound like a chandelier falling to the ground.
No there is plenty of room for that hose. I plan to insulate this shroud later as well.
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Thanks for indulging my questions!
Fuel drying, definitely simpler than torrifying, that makes sense.
Over and over it seems we can save complication by splitting up some steps.
Like making charcoal and using it in a gasifier, rather than using a wood gasifier, which itself has to produce charcoal as it goes.
Refine your gasifier fuel into charcoal and refine your charcoal feedstock with the heat produced by the process.
About the wood chips added to the fuel hopper, would/could torrify by virtue of their size?
The bigger fuel has to become charcoal before it will pas through the grate, while the woodchips steam, dry out, torrify and fall through without necessarily charring or burning up?
Any that does burn up simply fuels the process.
What do you think of a second grate and loading port to go with the top fuel hopper barrel?
Wood chips on top, sitting on a 1" square grate, drying and cooking until they fall through, past the chunky fuel and the bigger grate into the charcoal catch bin below.
Needless complication?
What kind of insulation where you thinking of for the shroud?
Ceramic wool might be good on the inside, rock wool would be cheaper and heat resistant enough if its not in contact with flames.
I just tried out my boiler last night, it definitely needs some insulation, among other things.
Exactly!!
Yeah I think just keeping it simple will be king. But you never know as we learn new ideas tend to crop up and then we evolve.
I was just thinking home residential insulation. It works. Wrap the barrel and then wrap some tape around it. I was then planning cutting a 55 gallon drum top and bottom off and then cutting the seam. Then use a couple ratchet straps to compress it all and secure with zip screws.
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Easier to go to Home Depot and get a piece of pole barn metal.
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