new video
hot off the press!  
    more about rocket
mass heaters here.
  • Post Reply Bookmark Topic Watch Topic
  • New Topic

rocket stove and natural gas chimney  RSS feed

 
Ivo Gregurec
Posts: 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hello!
Excuse me if this subject has been already discussed but I haven't found any topic... Since the exhaust from the rocket stove mass heater is very clean (H2O+CO2 = basically a sparkling water ) would it be theoretically possible to plug it in the smokestack designed for natural gas based heating systems which are pretty common case in the apartment buildings?
As far as I know those kind of smokestacks are coaxial where the inner tube (diameter = cca. 15cm) is designed for exhaust and the outer provides oxygen for combustion.
 
Miles Flansburg
steward
Posts: 3981
Location: Zones 2-4 Wyoming and 4-5 Colorado
166
bee books forest garden fungi greening the desert hugelkultur
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Howdy Ivo, welcome to permies!
I am still learning about this too. What I think I have heard is that the exhaust from rockets also tends to be cooler. Most traditional exhaust is hot or warm enough to go up the stacks due to heat rising. So you may not have enough heat from a rocket to rise very far? Maybe someone else will comment on that.
How tall are the stacks you are talking about?
 
Ivo Gregurec
Posts: 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hey Miles!
Stacks I'm talking about are hypothetical and it depends of how many floors building has... I guess not taller then 50 - 60m... but in most cases less then 10m. It also depends on which floor the stove is placed.
I don't understand the fluid dynamics that much but a good stack has a tendency of suction, and on the other hand it is much harder to set fire in completely cold stove with cold stack.
I hope someone could explain that little bit better.
Miles Flansburg wrote:Howdy Ivo, welcome to permies!
I am still learning about this too. What I think I have heard is that the exhaust from rockets also tends to be cooler. Most traditional exhaust is hot or warm enough to go up the stacks due to heat rising. So you may not have enough heat from a rocket to rise very far? Maybe someone else will comment on that.
How tall are the stacks you are talking about?
 
michael Egan
Posts: 68
Location: central illinois
1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
My experience confirms what your saying about tall stacks having lots of heavy air. I have a side loading batch rocket that eventually exhausts into a 26 ft. masonry chimney. If I start it cold in the rocket smoke will leak out of the top of the barrel for, say, 5 minutes. If I prime it by starting a little fire closer to the vertical masonry chimney it won't. I assume the preheat pushes the cold air sitting in the chimney out and gets the draw going. Here's a link of the rmh and you can see the stack from the outside. This video doesn't show how i prime it. i'll try and post that later.

Michael

 
allen lumley
pollinator
Posts: 4154
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
58
books fungi hugelkultur solar wofati woodworking
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
High to all : Periodically I weigh in on a tangent of this subject and it needs to be covered again.

Basically there are 4 types of fossil fuel and biomass heaters that can be operated in a highly efficient manner.The two most
Expensive we can quickly disregard, a municipal incinerator; too many controls, needs a trained operator, often permitted to allow it to burn
'dirty' several hrs a cycle. The Masonry/Mass/Russian Heater, The person operating the system can learn by rote how to use this system
with good results. It still can be used poorly especially when the system is cold, 2nd most expensive system to install, all but the most simple
maintenance involves extensive ,time consuming,and expensive repairs by an expert on 'his' schedule !

Now we have just the Newer High Efficient propane/nat Gas Heaters and of course the rocket stove models, we are in much danger when
we try to compare these last two ! The Rocket stove must always be treated as producing Carbon Monoxide in its exhaust !!!

The newer gas heaters with their horizontal discharge, and air/heat Exchangers can be burned at their stated high efficiencies, if installed
correctly! Be aware that most of these Heat Exchangers use a required fan to move the air necessary to cool the exhaust and provide the
Air for combustion. Fan Failure or loss of electrical power will stop this heater from working !

When the gas heater is sold to the consumer (somewhere on a showroom floor ) the salesman says 'when this heater burns its gas, it
produces only Carbon Dioxide and water vapor, and our Air/Heat exchanger is so efficient that its exhaust can be run to the outdoors thru
this plastic pipe!'

Things the Salesman doesn't say are -' But we have local zoning laws that require 3-wall metal pipe and insulated thimbles', Also'This heater
is designed to use a Horizontal Exhaust/Heat Exchanger mounted on the Lee-wall (out of the path of prevailing winds)

When the workman shows up for the installation, the new owner 'says mount it to that wall right there next to my rocker.' Catastrophe !!!
The wall selected is not an outside wall - use silver metal pipe or plastic pipe to run the exhaust acrost the living room to a suitable
spot on an outside wall
Consternation, Idea, owner reluctantly agreed to move the heater to an outside wall - now its no longer 'heating'
'just the space that YOU want it to"!

The workman 'certified installer' does not know,or want to know at this point, where the prevailing winds are, he just wants to complete the
installation! With a square/rectangular house, he has a 1 chance in four of hitting a spot on a lee wall ! Because this unit is now installed
subject to prevailing winds, there is smoke back, this causes a dirty exhaust and soot on the outside wall of the house. The solution here is a
vertical chimney up as high as the eaves or even several feet above the highest point of the house ! Often this step is never done and the
soot just gets darker and darker on the outside of the house, as ugly as 'brown stains in your shorts', and advertised to the whole neigh -
-borhood !

This problem with the exhaust of a gas heater exposed to contrary prevailing winds is also common to Rocket Heaters, the difference here is
that the Rocket Stove will smoke back into the room, alerting the Owner of the problem , and again the answer is move the Rocket, or add
extra vertical stovepipe and a storm cap.

While the Exterior Wall mounted Gas Air/Heat Exchanger will further cool the exhaust temps of a Rocket Stove, it would still need to be sized
appropriately. this could only be determined by trial and error and needs research, My H.W.A. Guess is nothing smaller than 5'' interior exhaust
pipe for a 6'' Rocket ! This still leaves delivering the make-up air that is the necessary air stream to cool down the exhaust gas stream.
This is almost always a forced air system, are you going to plumb it into your Rocket, and attempt to make a forced air system out of it ?

I hope this clarifies the many Faults of a lack of prior planing - how and where to pipe your exhaust, and gives useful examples of why the
horizontally exhausted Burners so often fail to deliver as promised. For the good of the Craft! be safe, keep warm, PYRO Al
 
I agree. Here's the link: http://stoves2.com
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!