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rocket stove problem  RSS feed

 
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Hi Everyone
Newbie here, can you help
Problem Water [steam] staying in my horizontal pipework;
I have just constructed a rocket stove in my basement, basically there is 10 meters of horizontal pipe work which then rises 2 meters, 6 feet then it goes into a 90 degree bend through a concrete wall into a J tube, and is then rises vertically [outside the house] into metal chimney approximately 3 meters in height, a total vertical height of 5 meters, 16 feet.
The burn chamber seems to be burning well, and roaring, all the pipework is 150 mm, 6 inch, the J tube which goes through the wall is cob insulated, the 150 mm 6 inch chimney pipe is insulated with rock wool, and has been placed inside a 200 mm 8 inch pipe.
The heat riser is constructed of fire brick, I have put a metal sheet around the heat riser and then packed it with cob, a metal drum has been placed over the heat riser the gap between the top of the burn chamber and the barrel is 3 ½ cm, 1 ½ inches.
The gap between the heat riser and the barrel is 7 cm, 3 inches; all round, the burnt gasses are diverted into a box which connect to the 10 meters of horizontal pipework, and then rises into the J tube and then the chimney.
I have two possible cures to my problem the first one is that the gasses, steam, are basically not getting enough draw from in the chimney? Which is why the steam /water are staying in the pipe work ?
My second thought is that the fire clay, and the cob are not yet dry and this could be adding to the problem?
If anyone can advise on my problem I would be grateful to hear from you.

 
pollinator
Posts: 4154
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
59
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John Traynor : If you have a decent roaring fire in your rocket mass heater, then you do not have a problem with draw, and I think that you are going to
find that most of your problem will go away after your Cob gets a chance to dry. Further, when everything does dry, your wood consumption will diminish
by a 1/3rd! Assuming you are burning very dry wood !

As long as you have a good storm cover over your 8'' pipe to keep the insulation dry between the two layers of stove pipe I think that you will be fine!

I hope that you have mis-typed what you wanted to report regarding the way you have fixed up your Heat Riser ! Around the outside of the Firebrick
Heat Riser you have placed a 'metal sheet ', I am assuming that it comes up the outside of the Heat Riser to an equal height,and that you have made
a final cap of Perlite and Clay Slip, or Cob and Perlite to within the magic 1.5 inches of the top, ( that is a minimum distance !)

You have typed that you filled the metal sheet you wrapped around the Firebrick with Cob, you should have been able to just pour in Perlite or Vermiculite
though I would have recommended Perlite, after you had brought the Perlite up to the top of the Metal sheet and the Firebrick, a simple mix of Perlite
and Clay slip should have sealed the Top of the Perlite.

Depending on how wet you made your cob, I am assuming you packed it in, tamping it down and didn't pour it in like filling a bucket, it should not be much
wetter than a mix of perlite / clay slip !

After the end of your burn, and your fire is out, your barrel will take longer to cool down ! Nothing wrong there!

All and all, I think you should just try living with it until next fall and rebuilding it in warm fall weather !

I am confused by the layout of your pipe, are you trying to put two wood burning units in the same pipe ! Does your Vertical pipe clear the Peak of your
houses roof, 16 ft does not sound very high !

Is there any way you could send some pictures ! For the Craft ! Big AL
 
John Traynor
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Hi big Al
Thank you for your reply I have attached 3 photos and I'm going to attach some more on a few more posts because 3 is the maximum amount per post.
If you look at them you will get a better idea of what I meant in my previous post.
Thank you for your advice and i hope you will be able to advise me further.

Answering some of your questions :

My house is 4 floors high, and I'm constructing the rocket stove in the basement so I am hoping that I do not need to take the chimney pipe up to the roof level, [fingers crossed.] I will put a cap on the top of my chimney pipe to keep the insulation dry. The pictures that I am sending should give a clearer view of what I have done so far, I'm just hoping that there is no problem with me sending the extra pictures I intending to send, 12 in all.

John
1.JPG
[Thumbnail for 1.JPG]
stove pipe lay out
2.JPG
[Thumbnail for 2.JPG]
exhaust box
3.JPG
[Thumbnail for 3.JPG]
exhaust pipe up through the wall
 
John Traynor
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More pictures
4a.JPG
[Thumbnail for 4a.JPG]
Brick heat riser
4-b.JPG
[Thumbnail for 4-b.JPG]
Metal sheet around the heat riser
5.JPG
[Thumbnail for 5.JPG]
cobing between the brick heat riser and metal sheet
 
John Traynor
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And more photos. AL
6.JPG
[Thumbnail for 6.JPG]
finished brick,and metal heat riser
DSCN0229.JPG
[Thumbnail for DSCN0229.JPG]
Metal J tube
 
John Traynor
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Well that's it for now Al, I hope that the pictures give everyone a better idea of what I have done. hopefully when the fire clay and cob has dried it will resolve the problem

Thanks John
DSCN0253.JPG
[Thumbnail for DSCN0253.JPG]
position the J tube, and attaching chimney pipe
DSCN0254.jpg
[Thumbnail for DSCN0254.jpg]
chimney pipe 3 meters up the side of the house
 
allen lumley
pollinator
Posts: 4154
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
59
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John Traynor : You have a very fertile Mind, and all of your adaptations from other builds you have seen are natural products flowing out from there !

Do you have previous Cob Experience ? The Type of Cob you have placed around the outside of your Firebrick heat riser is called Structural Cob, and is highly
insulating.

Because early on in a Rocket Stove build this is not a beginners technique, and there is a danger to the plumb and level-ness of your firebrick tower
most rocket mass heater RMH Instructors would rather show the pour in Perlite and Cap with perlite and Clay Slip !

We DO NOT want to use Structural Cob to wrap around the horizontal piping of the Thermal Mass,it is too insulating, Instead using a straight 30% Clay
70% Sharp or Builders Sand this will also deal with moisture / high humidity swings better than cob with straw in it! (I THINK)!

The Structural Cob Should be saved to make a layer ~2''~ or 6cm thick as an outside layer around the Whole Cob Thermal Bench before the finish layer coat
is put on!

At the wall behind your RMH the use of An insulating reflective material is very much like what we want, a reflective barrier with a 4'' air gap both sides and
air exchange will serve you better !

I am not very concerned about too much Heat Energy radiating down through your Cob Thermal Mass Bench, But directly under the Rockets Burner Base,
and the Transitional Area, you you can have problems with the slow pyrolyse-ing or out-gasing of the wooden parts of your floor even at quite low temps, this
will eventually reduce the woods integrity, and lower the kindling temps to match light charcoal, though this will take decades, this is not a thing you want to
pass on with pride ! This does happen even faster to wood exposed to UV rays, or water damage and weathered to a uniform grey !

This is also a good place for air gaps by making brick channels underneath, and adding backer board and a reflection layer, even if it is only shinny side up cooking
grade Aluminum foil. This is also a good place for packed Perlite and Clay slip or Structural Cob, but I would hesitate to guess how thick it should be !

The Great Deliberative Minds that Run our Countries remind us that They must remain ever vigilant, that they 'have to be right every time', and 'the Bad Guys,only
once'.

You need to be prepared for the Storm of the Decade, that comes out of a different direction than the prevailing winds of a 'Normal Heating Season'! This could
easily cause the kind of backdraft issues that would make using your RMH difficult / impossible in the middle of a several day storm !

I highly recommend that you take the time to Google ''Stack effect'' and ''Whole House Stack Effect'', as a minimum, your chimney must be located higher than the
highest window that could be opened on your house, if you have attic vents with openings in your soffit and facia, and vents at your roof peaks, your minimum
just got higher! The builders recommendation would be 1.5 meters above the Peak !

This turned out to be a little more negative than I had intended, Again I am impressed with your 'thinking outside the box', we get stuck in our ways and want to
argue when people have radical new ideas, but people like you are the future of rocket mass heaters Of all kinds ! I hope this is timely, and useful, send more
pictures ! For the Good of the Craft ! Big Al !

Late note : Is that bubble wrap up against your houses foundation, Next to last picture ?!! In the last picture I see what looks like a drier vent exit through the Wall,
While you are studying up on "Whole House Stack Effect'' you should be aware that It is likely that Running any power vented air exchange devices, driers, gas
hot water heaters, bathroom and kitchen vent fans can negatively affect your RMHs performance ! A. L.
 
John Traynor
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Hi AL
My first reply bombed out, internet problem, second reply, questions answered in order.
Thanks for your comments.
Experience gained listening to you tube, and including general building experience.
I plumbed the chamber first using fire clay for the brick joints I let it set and then tamped the structural cob in place.
I used 3 sand 1 clay with water to encase the horizontal pipes, as mentioned by Erica and Ernie in there you tube classes.
I do intend to put a 2/3 inch layer of cob on top of the fire clay encased pipes, and then a final coat of fine cob mix.
I will remove some of the cob between the reflective barrier and the mass to create an air gap.
The transitional Area that you mention, The floor does look like wood but it is in fact a tiled floor, thanks for the information on out gassing this was a new one to me.
What I did before construction the rocket stove, was a layer of insulation, then a sheet of plasterboard, then a aluminium reflective sheet, a layer of construction bricks, then the rocket stove its self using fire clay to construct.
I have taken on board your comments regarding the chimney, and have started to plan increasing its length
Hey AL your comments re this turned out to be a little more negative, don't worry about it if you don't ask you will never know.
AL I have a question; out gassing; I have used polystyrene insulation to create a heat barrier [picture enclosed] then I filled in with rubble and soil, then 2 inches of cob, finally laid the horizontal pipework, will the polystyrene out gas?
The bubble wrap you mention is a hydro insulation which keeps the damp from penetrating the building, the vets that you mention is a natural air floe vents for my stair case.
Thanks for your comments
John
1.JPG
[Thumbnail for 1.JPG]
under the rocket, insulation, P/board, construction brick
2.JPG
[Thumbnail for 2.JPG]
same as above pic on the left you see aluminium reflector, and burn chamber set out. in levels
3.JPG
[Thumbnail for 3.JPG]
first level of in fill, polyistireen, rubble,soil, 2 inches of cob, then pipework
 
allen lumley
pollinator
Posts: 4154
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
59
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John Traynor : Sorry it took so long to get back to you, family comes first. We had an outing, and came home over 4''-6'' of 'Wintery mix' on the roads!

Lets get the polystyrene Foam out of the way ! I got my information from google ! It is not recommended where temperatures will be above 80 degrees C,
(the fact that you can smell new Polystyrene foam means it is outgassing ) This means it should not be used around the Rocket Burner, The Rocket Burner
Base, the Transitional Area, and the 1st 4'-5' of the horizontal piping of the Cob Thermal Mass, after that you will want a layer of Aluminum Foil Shiny side
up, preferably one layer of bricks or other insulation above !

Please go to richsoil.com, and find the rocket mass heater listing on the left side of the home page, Clickon=>and watch the whole series of videos,
specifically I want you to see how to pretreat your Barrel, your 1st clean out 'T' and first two lengths of horizontal pipe to change the way the Zinc coating
is mechanically bonded to your stove pipe ! This is also a safety and outgasing issue, not pretreating the barrel to remove all paint and residues from inside
the barrel, is a bad idea !

I do not understand your statement, that you are going to add just 2/3 inches over the horizontal pipes, did you mean 2'' to 3''? More is better, you may
be looking at your piping snaking across the floor and saying to your self, I hope this is worth not ! this is using up lots of room ! Think of it this way , thicker
cob, tall enough to actually make a true Thermal mass bench will capture and store more heat than less come and by being at a comfortable sitting height
will be a lot more handy than a truly impractical shorter covering !

The highest minimum temperature you should be prepared to accept is about 75 dC at the last clean out before you go out doors, if you have that with very
shallow Cob, you can live with that, or add more to give you a custom built piece of Built in furniture that you will enjoy lounging on !

Consider going to Village Video villagevideo.org, from the home page, clickon=> the You tube icon, then at the new page you will see a group of short
videos, the 1st row is labeled rocket mass heater Scenes, to the right is a button labeled '' PLAY, click on that button which will load 19 short
videos ~3/8ths~of one of Ernie and Ericas up scale builds, This series of videos is put together as a teaser to get you to buy the video, I am encouraging
you to watch the free part and make up your own mind ! For the good of the craft ! BIG AL !
 
John Traynor
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Hi AL
Thanks for your comments, I take on board what you say, and I will watch the videos.
cheers John
 
look! it's a bird! it's a plane! It's .... a teeny tiny ad
five days of natural building (wofati and cob) and rocket cooktop oct 8-12, 2018
https://permies.com/t/92034/permaculture-projects/days-natural-building-wofati-cob
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