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Post by drpohl on Apr 10, 2015 11:49:50 GMT -8
Its been a while with over 100 views and no one has an explanation or calculation basis to suggest for the space distance between the top of the riser to the tank top? Think I'll try using larger CSA than the riser's CSA to allow for expanding hot flue gases... maybe three to five times? Peter suggested 12" space for a 6" riser but I didn't see any explanation - just a suggestion... would like more "science" with math... is Peter the only one with an "idea"? How about the other moderators? What say you?
Thanks in advance!
Doug
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Post by peterberg on Apr 10, 2015 12:34:48 GMT -8
For an explanation, see my reation of 4th April. When nobody answers, you are perhaps asking for calculations which don't exist? You want more "science" with math. Here's your opportunity to work it out and enter the hall of fame yourself.
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Post by drpohl on Apr 10, 2015 15:16:10 GMT -8
I think you have identified the problem... so many people want to learn but without a qualified instructor it seems this forum has years of chatting under its belt but keeps going round and round and not solving several of the remaining design issues - I can understand the cost of instrumentation but several forum members/moderators have it and still have not publicly stated results regarding the mentioned issues... and as you say "When nobody answers, you are perhaps asking for calculations which don't exist"... which begs to ask the question "Why has so many people built their stoves/heaters if not to solve the mentioned issues? The least they could do is report back what works for them... Peter, I think you are playing your cards close to your vest since this is as you said "not a consultancy".
I see Pinhead? has online related stove/heater simulators - but I am unable to move anything around to change variables - just nice animations - so once again what appears to be an expert is holding his cards close to his vest.
Thanks for you help to date... it was educational while it lasted... and since I'm not into commercial stoves/heaters for any hall of fame ribbons... I'll just have to build and optimize with trial and errors... maybe I can report back to those who actually helped... lol
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Post by DCish on Apr 10, 2015 16:26:08 GMT -8
IMHO, there is very little "holding close to the vest" on this forum. In fact, I find it remarkable the patience with which Peter and others answer the same questions over and over again as new folks join the forum. This is a forum for folks to share experimental experience, not product support page for a polished commercial device with a guidebook of final answers. Regarding "Why has so many people built their stoves/heaters if not to solve the mentioned issues?" I would offer the idea that it is because the estimates offered have thus far been "good enough" for builders to achieve results acceptable to them. As folks experiment and share, the body of knowledge grows. As folks experiment and tinker, they tend to focus on optimizing one part or another when the lack of information bugs or intrigues them. I hope that you will build, optimize what concerns you most, and share your results in the spirit of generosity that I find the majority of this forum embraces.
Most Respectfully, DCish
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Post by ericvw on Apr 10, 2015 16:47:34 GMT -8
IMHO, there is very little "holding close to the vest" on this forum. In fact, I find it remarkable the patience with which Peter and others answer the same questions over and over again as new folks join the forum. This is a forum for folks to share experimental experience, not product support page for a polished commercial device with a guidebook of final answers. Regarding "Why has so many people built their stoves/heaters if not to solve the mentioned issues?" I would offer the idea that it is because the estimates offered have thus far been "good enough" for builders to achieve results acceptable to them. As folks experiment and share, the body of knowledge grows. As folks experiment and tinker, they tend to focus on optimizing one part or another when the lack of information bugs or intrigues them. I hope that you will build, optimize what concerns you most, and share your results in the spirit of generosity that I find the majority of this forum embraces. Most Respectfully, DCish HERE, HERE! Well said DCish, if not actually concisely perfect! To the patient helpful moderators, I say thank you and Cheers!
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Post by DCish on Apr 10, 2015 19:09:43 GMT -8
HERE, HERE! Well said DCish, if not actually concisely perfect! To the patient helpful moderators, I say thank you and Cheers! Argh! Pasted the less edited version! Oh well, the spirit of what I was trying to say is still there in this rough draft...
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Post by satamax on Apr 10, 2015 19:15:40 GMT -8
And what if it didn't matter that much?
As long as your top gap is big enough, you can increase it, seemingly, up to a practical point and cooling point.
Practical point, well, you won't be building several storey high bells or radiators.
Cooling point, or may be dew point, is when your bartrel surface will be too big, that your stove cools off, and stalls.
That last bit of information is around on the forum.
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Post by pinhead on Apr 13, 2015 4:58:25 GMT -8
I see Pinhead? has online related stove/heater simulators - but I am unable to move anything around to change variables - just nice animations - so once again what appears to be an expert is holding his cards close to his vest. The simulations I built and were posted to the energy2d site should be completely customizable. If you can't move the components around you probably have a problem with your Java installation. I use Firefox and have used Chrome. Both should work. But I am nowhere near close to being an expert. I'd put Peterberg, Donkey, Matthewwalker, Satamax, and others leagues ahead of my knowledge. I'm just good with computers and try to help when I can.
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Post by satamax on Apr 13, 2015 23:12:08 GMT -8
Hey i'm no expert.
Just a dumbass who can see how two components might assemble.
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Post by pyrophile on Apr 14, 2015 0:13:32 GMT -8
I also admire Peter and all moderators who have patience enough to answer to everybody with a lot of care! I remember a guy on a french forum dedicated to mass heaters who did many many calculations but never made his stove... The forum is open to everybody and we are happy to share and to learn with everybody, with more scientifical knowledge or with more practical experience, or both! If we don't offer what you would like to find, maybe you can help. Welcome! Sincerely!
Maybe also, on certain points, we did not find the interest for them. Orfor other points, it is a matter of choice and maths don't help! Do you want to cook above the heat riser (few centimeters) or to store heat (lots of space)? Sometimes you would need to much maths, to big a simulator programm to try to solve (or even not!) a problem already solved for years and which you can find the solution easely here or somewherre else.
Benoit
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Post by Donkey on Apr 22, 2015 19:49:08 GMT -8
I think you have identified the problem... so many people want to learn but without a qualified instructor it seems this forum has years of chatting under its belt but keeps going round and round and not solving several of the remaining design issues - I can understand the cost of instrumentation but several forum members/moderators have it and still have not publicly stated results regarding the mentioned issues... and as you say "When nobody answers, you are perhaps asking for calculations which don't exist"... which begs to ask the question "Why has so many people built their stoves/heaters if not to solve the mentioned issues? The least they could do is report back what works for them... Peter, I think you are playing your cards close to your vest since this is as you said "not a consultancy". I see Pinhead? has online related stove/heater simulators - but I am unable to move anything around to change variables - just nice animations - so once again what appears to be an expert is holding his cards close to his vest. Thanks for you help to date... it was educational while it lasted... and since I'm not into commercial stoves/heaters for any hall of fame ribbons... I'll just have to build and optimize with trial and errors... maybe I can report back to those who actually helped... lol @drphol, My understanding is that everything that is now known about these stoves can be found here for free, just your time to look. Chances are, if it's not here, it has not yet been quantified or verified by test. Peterberg and others (myself included) have spent thousands of man-hours of work to discover what is now known on this subject, they (we) have given it all away to the community and held none of it back. While much has been discovered and quantified, there is still much to discover. If there is some area that is still grey and you want more information, if a lack of data is burning a hole through your need to understand, I suggest you lend a shoulder! Can't find an adequate answer to your question? Solve it yourself and give back as others have done before you. Build a test bed, define experiments, do the tests and contribute! Return with results and share, it's what these forums are FOR. If on the other hand, you just want to build a stove that works; rules of thumb will build suitable heaters (which is the goal) without all of the hyper-numerary hair-splitting. One can get on with it using current information (found freely here) and produce one of the finest heaters available.
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Post by Donkey on Apr 22, 2015 20:14:45 GMT -8
To answer your riser/barrel gap question: Firstly, there is the L-tube feed, J-tube feed and the Batch-Box; they are all different, have different parameters and probably should not be mixed and matched too much. With the J-tube barrel dimensions, traditionally gaps were given to avoid pinch-points. Heat characteristics, when noted at all were noted in very limited ways; Ianto noticed that his tea water seemed to boil faster with a tight top gap, I noticed that the barrel seemed to give more heat to the room with large top gaps, Peter added bell technology and changed the conversation completely; none of us developed a formula to describe what we experienced. As to the gap difference where it applies to the Batch-box: it is my understanding that the larger gap is a best guess, it's a recommendation to avoid overheating of the barrel-top. Batch-boxes dump far more heat, moment by moment, than the other types of RMH; with such an overload of heat, the barrel top can be in real danger of failure. No formula has been discovered or put forward, all of the information has been empirically derived.
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Post by drpohl on Apr 25, 2015 17:54:48 GMT -8
Interesting how formulas by one turns into empirical for others... Yet admins say its all here (on forums)
IMHO I wouldn't build anything that is technical without taking the time to detail it out (in my favorite graphics program)... others are welcome to do as they please... not my place to say its right or wrong... rolling the dice just doesn't work for me to build without a starting basis... so when no one knows... it raises a flag... more work needed.
Sure its all "here" (forums) but I've been reading for months and still cannot find anyone who "knows" an answer basis for the questions asked... empirical just doesn't work for me... so I'm waiting on some testing equipment so I can better engineer with hard temp and combustion data... the devil is in the details...
The biggest improvement that all could make on the forum is to add a drawing... since terms change and not accurately used by all... but a drawing overcomes the obvious limitations. Just try and read someones description and you can only scratch your head... if there was a drawing it would be much simpler to communicate.
Thanks to all who took a stab at this...
Standing by :-)
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Post by DCish on Apr 26, 2015 11:37:45 GMT -8
... so I'm waiting on some testing equipment so I can better engineer with hard temp and combustion data... Cool... What equipment you got coming?
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moss
New Member
Posts: 1
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Post by moss on Nov 14, 2015 23:43:43 GMT -8
Peter my 1st post very new to the discussion. I'm building my 1st Rocket Mass Batch Heater. Could you supply me with Batch box size Height x Width x Length, S-portal size Height x Width,riser height, with a 6" Internal Diameter riser. I plan on constructing the 6" riser out of refractory fire bricks that can be easily cut and cementing them together with refractory cement when laid on their side will give me a wall thickness of 4-1/2" and I'm hoping no further insulation of the riser will be necessary. I plan on using the floor channel under the firebox to supply air to the s-portal.I would like to build a system utilizing 3 55 gal drums the first 2 stacked on top of each other and the third 55 gal drum on the ground accepting the exhaust from the system and then leading to a 6" chimney pipe that leads outside. Do you think 8" round for the exhaust between the 2nd and 3rd barrel is big enough? Any help would be greatly appreciated. I would like to post my results when finished.
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