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Post by laurens on Aug 26, 2015 0:50:45 GMT -8
Hi there,
In a couple of days I want to start building my next rmh. I already made two Ianto Evans style heaters, but I want to try a "peterberg batchbox bell system" now. The house I'm building the heater in has a chimney with a 110mm diameter pipe inside.
Is it possible to connect the batchbox bell system (as it is in Peter's sketch-up file) to this 110mm pipe?
Or does the csa of my heatriser need to be smaller (or equal) to the csa of the chimneypipe going out of the house?
Groets uut Drenthe.
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Post by satamax on Aug 26, 2015 1:26:46 GMT -8
Laurens, you might be able to get away with a 12cm diameter system.
If your natural draft is real strong, may be even a 15cm could be done, providing you leave enough heat to keep the draft strong.
But that would be the absolute maximum.
When you say pipe in the chimney, you mean it's lined with bendable tube? Or is it old style, cast in place pipe? If the first option, your chimney flue might be bigger, so de-lining it could be an option. As a rmh doesn't produce much soot, and neither much heat in the flue.
Hth.
Max.
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Post by peterberg on Aug 26, 2015 1:42:20 GMT -8
I agree with Max, a 15 cm riser is 1.86 times as large as the 11 cm chimney pipe, csa-wise. You could get away with that provided you use a chimney fan. The chimney need to be equal or larger than the riser csa, so there's not much of a choice. There's two choices then: de-lining the chimney and line it again with a 15 cm flexible stainless pipe or use a fan.
Or, build a real small system but I won't advise that for a normal occupied house.
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Post by laurens on Aug 26, 2015 1:46:03 GMT -8
Tanx Max,
I have taken another (read, better) look and see that it's only a short piece op pipe at the beginning of the chimney. the rest is just a big masonary chimney going al the way through the house. And then there is another piece of pipe comming out of the top outside.
If I understand correctly, this is a good thing, right? It's already "de-lined" as you say?!
Groets, Laurens
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Post by laurens on Aug 26, 2015 1:51:34 GMT -8
Thanx Peterberg,
You mean I need to place a bigger pipe inside the chimney? Or can I just replace the pieces of pipe going in and out for bigger ones?
Groets Laurens.
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Post by satamax on Aug 26, 2015 4:10:05 GMT -8
Get rid of the pieces of pipe, and tell us what is the size of the chimney then!
The house must have has a stove at some point, with the 110mm pipe. May be coal even. You might not even have to replace the pieces of tube.
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Post by laurens on Aug 26, 2015 5:59:52 GMT -8
The inside of the chimney is aprox 30x40cm.
And indeed the house had a small woodstove a while back.
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Post by laurens on Aug 26, 2015 6:33:09 GMT -8
How it looks on the outside How it looks from the inside, its now a hole in de groundfloor ceiling.
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Post by peterberg on Aug 26, 2015 6:57:54 GMT -8
A good chimney stack need to be everywhere the same size, round, smooth and insulated. This masonry thingy is far too wide, rectangle shaped and probably not smooth as well. And at the top and bottom end there appears to be a severe restriction. So I'd recommend to line it over its entire length with a pipe which is the same size or slightly larger as your intended system size. And of course, take the trouble to fill the space around the liner with perlite or vermiculite.
A well-made batch box will run beautifully when equipped with such a stack, quaranteed.
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Post by satamax on Aug 26, 2015 13:23:32 GMT -8
Peter, if he has rooms to heat on the way, he could also use that as a "semi bell" 20cm pipe feeding in it, 20cm pipe going out on top of it. And slowed down gases on the way, which exchange their heat with the surounding massonry! I would be inclined to such a solution myself
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Post by peterberg on Aug 26, 2015 14:22:11 GMT -8
This would be a very interesting experiment. But not for the faint-hearted or the absolute beginner. In my opinion you are neither of those, don't get me wrong. For the novice I would say: stick to the tried and tested numbers, that would generate the best chance for succes.
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Post by Dan (Upstate NY, USA) on Aug 26, 2015 17:42:37 GMT -8
I disagree. I have a heat riser on a common J-tube that is 8" or 20cm that goes through 30 feet or 9 meters of 20cm pipe and then connects to a 6" or 15cm pipe. This is approximately 1/2 the area. I can get away with it because I cool the gases enough to to reduce the volume of the gases by 1/2. My exit temperatures are about 130F (average) or 54C. I do have to start a small paper fire when the stove is cold in the last cleanout. I DO NOT have to use a draft fan. Going in our 4th season now... Link to photos...
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Post by satamax on Aug 26, 2015 22:26:26 GMT -8
Wolf, may be it's easier because there's less air passing through the J than the batches. Far less risk of overfueling too.
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Post by laurens on Oct 28, 2015 11:36:50 GMT -8
The new rmh is done! My girlfriend just finished putting on the last bit of cob All i need now is a piece of glass for the door (it's now a piece of metal, but I would really like to see the flames ). Can I use normal glas fot that? goo.gl/photos/Pe6U6fWgJp7Jjw8Q6By the way, I went for satamax' "semi bell" idea and it's working like a charm. It's a 15 cm system, with a 13 cm pipe going to the bigger chimney. And there's also a small piece of 13 cm pipe on top of it. Tanx a lot for your help.
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Post by satamax on Oct 28, 2015 12:38:54 GMT -8
Not too shabby looking thing ! So, does the massonry of the chimney gets hot? I've used this type of solution in my early experiments, and it sure works. I used 35kg gas bottles, as the bottom flue, after the rocket. Gasses were going through theses like a chimney, exept it was far wider than the 110mm pipe i was using for my 6 incher J. I tried to turn that one into a bell, and it was working far worse than the enlarged chimney.
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