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rocket stoves

Extra tall RMH bench- Would this work?

Posts: 39

Location: Vermont, USA

posted 9 years ago

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Hello wonderful RMH people, I've been studying forums and videos for years now, planning to build my own RMH in 'the future', and here's an idea I have not seen yet... has anyone done this before? Any predictions on how well it would work? I can't see any flaws in the idea below but if you do, I'd love to know!

This is my first post on this forum, so hopefully the scan above shows correctly. Basically the idea is to use a simple, reliable RMH design, but instead of running the heat duct the whole way through a thermal mass at shin level, I'd like to loop it back above itself, making the bench taller. If that description is vague, here's more detail on how air moves through the system:

1. down into feed tube
2. horizontal through burn tunnel
3. up the heat riser
4. swirls down the barrel and into a manifold with cleanout
5. enters horizontal duct at shin level
6. turns 90 degrees straight up (there's another cleanout here)
7. turns 90 degrees again, doubling over itself, heading horizontally back toward the barrel
8. before the duct hits the barrel, it turns 90 degrees straight up, to exit through the roof

This would create a tall, extra-heavy bench, requiring a strong foundation. One major benefit is that it cuts down on the footprint for the whole system, making it easier to fit into any floor plan. I imagine the duct-work being 20-25 ft in all, and then the chimney adding about 10ft vertical.
-Richard

shilo kinarty

Posts: 110

posted 9 years ago

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it will work
why do you want it that way?

Byron Campbell

pollinator

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Location: US, East Tennessee

posted 9 years ago

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Richard, that idea will work. Actually, it has already been done RMH style. That is a space saver too, a compact footprint, being built in the configuration of a narrow masonry "wall". Your drawing kind of reminds me of the Russian stoves/heaters built as a tall narrow wall separating halves of a house, thus warming both sides.

best regards, Byron

allen lumley

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Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''

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posted 9 years ago

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Richard Kniffin : Yes it will work, and may be ideal for some locations . What do you have in mind ?

Also the last elbow where the horizontal stovepipe turns to enter the final vertical chimney should be a " T "
as you should have a final clean-out at that location. For the Good of the Crafts ! Big AL

Success has a Thousand Fathers , Failure is an Orphan

LOOK AT THE " SIMILAR THREADS " BELOW !

Satamax Antone

gardener

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Location: Southern alps, on the French side of the french /italian border 5000ft elevation

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posted 9 years ago

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If need be, you can even go a step further

http://heatkit.com/research/2009/lopez-rocket.htm

God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY

Richard Kniffin

Posts: 39

Location: Vermont, USA

posted 9 years ago

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Thanks for that link Satamax, I'd never seen that before! Thanks to all others for your replies, as well.

I'm considering this kind of tall RMH to save floor space. I might want to build two of these RMH's side by side to heat a relatively large space in a cold climate, and stacking each one vertically is the only way I can imagine fitting them into my house plans. Two RMH's side by side might be absolute overkill, it's hard to tell, but at least a person could feed them simultaneously, saving time. Imagine that double-rocket roar!

This is a separate topic really, but would two RMH's burning next to each other cause any problems (cracking from combined heat, for example)? I don't have any math/engineering experience with this, but common sense tells me that if they were well-built, it would be no problem.

Satamax Antone

gardener

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Location: Southern alps, on the French side of the french /italian border 5000ft elevation

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Richard Kniffin wrote:

This is a separate topic really, but would two RMH's burning next to each other cause any problems

If they each have their own chimney, why not, but not in the same chimney, exept if it's a huge one. Just build a batch box rocket with bells, and you will be sorted.

God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY

Richard Kniffin

Posts: 39

Location: Vermont, USA

posted 9 years ago

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allen lumley wrote:Richard Kniffin : Yes it will work, and may be ideal for some locations . What do you have in mind ?

Also the last elbow where the horizontal stovepipe turns to enter the final vertical chimney should be a " T "
as you should have a final clean-out at that location. For the Good of the Crafts ! Big AL

Hi Al, yes the more clean-outs the better, good point! I'm not sure what you mean by location, but here you go...

Geographic location- New England, with 6-7 months of heating, regularly reaching 0F in winter, sometimes as low as -20F.
Location within house- along the southern wall, with the feed tube near the doorway, and fairly open rooms near the RMH so they can benefit from its radiant heat. Some rooms on the other side of the house could get chilly, hard to say for sure.

Glenn Herbert

Rocket Scientist

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Location: Upstate NY, zone 5

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posted 9 years ago

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What are the square footages and dimensions of the house? Unless it is spread out such that one radiant source will not heat it all, you would be better off building one larger system, in both initial expense and operating effort. A batch box burns its wood faster than a same-size J-tube with less attention, and you could make one large or long bell to store the heat.

Richard Kniffin

Posts: 39

Location: Vermont, USA

posted 9 years ago

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Glenn Herbert wrote:What are the square footages and dimensions of the house? Unless it is spread out such that one radiant source will not heat it all, you would be better off building one larger system, in both initial expense and operating effort. A batch box burns its wood faster than a same-size J-tube with less attention, and you could make one large or long bell to store the heat.

Hi Glenn, it's a total of 1,076 sq ft, and the dimensions are 24'x50' with deeply rounded corners (so it's almost an oval). The bedrooms are enclosed by walls and set further away from the RMH, but that's ok, we would prefer to sleep in the cooler part of the house. The RMH is directly on the south facing wall with tall windows so the bench can absorb some passive solar heat. We're not certain if one 8" RMH can pump out enough heat to keep such a house warm in northern new england... what do you think?

The batch box is something new for us to learn about, nice to see that option.

Glenn Herbert

Rocket Scientist

Posts: 4526

Location: Upstate NY, zone 5

574

posted 9 years ago

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I think the exact heating load, as determined by calculations, would be needed to gve an accurate answer. How well is the house insulated? Average for the region, or more so? What kind of walls? In the Northeast climate, you can hope for solar gain to bear a good portion of the seasaonal heating load, but you also have to plan for the alternate system to be able to carry the full load in a cloudy stretch. It does sound like one system will be sufficient - an 8" batch box system would be capable of serious heating with reasonable effort, and the firing schedule can be adjusted to suit conditions.
I do know that a house of similar size to yours in upstate New York shown in a video posted here is heated amply with one RMH, not even batch box fed.
https://permies.com/t/25435/rocket-stoves/video-great-rocket-mass-heaters

Satamax Antone

gardener

Posts: 3471

Location: Southern alps, on the French side of the french /italian border 5000ft elevation

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posted 9 years ago

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Richard Kniffin wrote:

Glenn Herbert wrote:The batch box is something new for us to learn about, nice to see that option.

Miself i think i would go for a 6 batch. May be even an 8 with lots of mass. Which would equal to less firing with bigger loads, so less time burning. I would never revert back to J tubes, as i think they are a chore.

Here's a nice batch which fits in a small place. You could enlarge the bell, and skip the bench too.

http://technologieforum.forumatic.com/viewtopic.php?f=19&t=27

I quite like the batches Adiel shows in his videos.

https://www.youtube.com/watch?v=xX3COtw_YnE

This one is quite big too! Even for a 6

http://batchrocket.hostoi.com/html/foto.html

I love the looks of this one too from Radek.

http://donkey32.proboards.com/post/15600/thread

Or Robert's one.

http://donkey32.proboards.com/post/15925/thread

Basicaly, once you know how to make a burner, J or batch, and you are able to determin what you need in terms of heat exchanger, i mean, barrels, bells, bench whatever. You can make your stove look any way you want pretty much.

God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY

allen lumley

pollinator

Posts: 4154

Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''

I like...

posted 9 years ago

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Richard Kniffin : This is perfectly compatible to your location, even the Northern Kingdom- And as you can see from outside shots this is a good sized

House with 2 stories, the 2nd story heated via a large open stairway with modest insulated drapes for temperature control - Note that when planned

as a piece of everyday use custom furniture its Central location becomes a BIG Plus ! Link Below :

https://permies.com/t/25435/rocket-stoves/video-great-rocket-mass-heaters

While both are interesting the 1st one is the one I wanted to share, located outside Canton N.Y.For the Good of the Crafts ! Big AL

Late Note : Have you gone to Rocketstoves.com to download a PDF Copy(s) Of the New #rd Edition of Rocket Mass Heaters, This is a must

for your library, It allows you to comeback here and share with your fellow members and using the same language to describe a RMHs Sizes, Shapes,

and the Orientation of its Parts to themselves and the Whole ! _ It is also the 1st book you will lend (to close and Trusted friends ) A.L.

Success has a Thousand Fathers , Failure is an Orphan

LOOK AT THE " SIMILAR THREADS " BELOW !

shilo kinarty

Posts: 110

posted 9 years ago

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Richard Kniffin wrote:

This is a separate topic really, but would two RMH's burning next to each other cause any problems

yes.
if one is with fire and one is cold, the cold one can cause draft problems to the hot one.
and then, if you try to light the cold one, chances that you will get a lot of smoke back from it (if you have a tight house)

one big RMH is more efficiency then 2 small

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