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Post by grizbach on Nov 19, 2012 9:03:20 GMT -8
Satamax, My bench is elevated off the floor 6" and the bottom of it is no where near as hot as the sides and top. It takes ALL DAY to get any heat down there.
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Post by matthewwalker on Nov 19, 2012 10:42:59 GMT -8
Max, the half barrel systems I've built indoors have mass below the barrels mainly to act as a seal. I set them in 4" or so of good sticky cob to seal around the bottoms, but I doubt the mass down there gets much heat as griz mentions. I never worry about the seal as the cob does a good job of sealing 'em up, but you could always weld them together and weld thin plate along the open "bottom" as well to make a sealed chamber if you were going to install it indoors and didn't want to use cob.
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Post by satamax on Nov 21, 2012 10:14:59 GMT -8
Thanks a lot Matthew. Well, got a nice drum today. Need to build a wooden bench and cut the thingy.
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Post by Donkey on Nov 21, 2012 17:22:30 GMT -8
A wooden bench?
How do you plan to couple a wooden bench to your thermal mass? Will your stove HAVE thermal mass?
Those half-barrels should get quite hot, I'd beware of contact between wood and the barrels or hot cob. And remember, when you char wood, you reduce it's flash (catch fire and burn) temperature DRASTICALLY.
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Post by satamax on Nov 21, 2012 22:27:40 GMT -8
Yep Donkey. Thought, none of the wood would be in contact with the barrels. i would put a layer of sand at the bottom, and cover them with mass. I wonder how hot does a bench gets? How low is the flash point of charred wood? 451F°?  I would have thought you'd have see this one before. www.youtube.com/watch?v=GkHOwmKyL7A |
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Post by Donkey on Nov 21, 2012 23:06:58 GMT -8
The autoignition point of wood itself is around 500 deg F.
The autoignition point of charred wood is around 200 deg F.
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Post by satamax on Nov 22, 2012 10:00:35 GMT -8
I should be OK then. I will leave a gap between barrel halves and wood of about 10cm each side and on the bottom. I don't think the mass can reach 100C° I need to find à way to airproof (gasproof) the halves on the bottom, without clay. And calculate what i need in terms of mass volume. What it will weight etc.
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Post by pinhead on Dec 7, 2012 12:56:20 GMT -8
Updates?
Petersburg: Where can I find a sketch of your latest and greatest design?
And satamax, how's your contraption running?
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Post by satamax on Dec 7, 2012 13:05:47 GMT -8
Mine is still in the workshop, i need to clean the bell. Well, i mean find time to do it. Then, i'll have to sort out the mass system. Half barrels. But it gonna take time, there's 40cm of fresh snow, i have two more veluxes to replace for à customer, and then i start working for the chairlift compagny i wok for in the winter. Kinda busy for the moment.
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Post by peterberg on Dec 7, 2012 13:28:39 GMT -8
Petersburg: Where can I find a sketch of your latest and greatest design? Sure, I've got a latest design, but it's more like a mock-up (or ugly prototype) than anything else. Don't get intimidated by this, and generate your own greatest design! I'm declaring the Worldwide BatchBox Rocket Stove Design Contest as opened! ;D Hurray! My own contribution to this contest have to wait until sometime next year... |
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Post by matthewwalker on Dec 7, 2012 13:36:18 GMT -8
I've been running my shop system lately, which is a Peter style firebox into 6" riser, 55 gallon drum into 3 half barrel bench mass. Did a P channel retrofit a couple days ago and played with that a bit. It's removable so I've been getting the thing hot, shutting the door, and then trying P channel vs. no P channel. It's been pretty fun. Nothing conclusive to report at this point. Oh, also, played with adding in some chopped fiberglass to my cheapo "refractory" mix I've been playing with. That looks pretty promising, although none of my mixes so far would be suitable stand alone. Wrapped in cob I think it's a viable technique.
One thing about the batch firebox coupled to the mass, it can really put a lot of heat into the mass. I feel like it's burning quite a bit hotter than my indoor system. I just yesterday finally got a little handheld IR therm, so I'll get some comparison temp readings tonight.
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Post by matthewwalker on Dec 7, 2012 13:37:38 GMT -8
Looks good Peter.
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Post by Donkey on Dec 7, 2012 16:37:33 GMT -8
Yeah, That's a thing that I've seen (but not measured definitively), the batch-box horizontal feed systems tend to dump a WHOLE lot more heat into the mass in a whole lot less time.
They tend to not burn as cleanly as vertical feed rockets, but boy do they produce heat!
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Post by peterberg on Dec 8, 2012 1:49:00 GMT -8
They tend to not burn as cleanly as vertical feed rockets, but boy do they produce heat! That's true Donkey, the standard unaltered J-tube will burn cleaner, but only compared to the unaltered batch box rocket. The same goes for both the optimized systems where the vertical fed rocket is the cleaner one of the two, though only marginally so. However, the optimized batch box do produce a much cleaner burn as compared to the standard J-tube. The latter has got the tendency to produce brief (one or two minutes) hydrocarbon spikes whenever the fuel shift down. The optimized version sports a higher tolerance to combustibles overload, that's why the spikes are flattened out. |
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Post by satamax on Dec 8, 2012 2:24:29 GMT -8
Peter, i have a question about tolerances. I could may be make a P chanel in mine. But i can't get to the very mouth of the heat riser. I have about 3cm of insulation in the way above. This wouldn't work for the P chanel?
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