Podcast 262 - Non-Metal Heat Riser

Hello,

If I understood the podcast correctly Ernie & Erica are recommending something other that metal pipe to form the heat riser if you can do it. Is it best to build the j-channel and heat riser all out of fire brick and then insulate around it? I have access to some good masons who will do a small fun project for beer and am trying to envision this in my head. A 7" (inside dimension) square J-tube and heat riser has a little less cross section as a 8" round pipe (if I did my math right). Does someone have more information on a masonry heat riser I can read about, preferably with pictures?

Making plans for a outside test build in the spring.

Thanks,
Jerry

Jerry Ward : Ianto Evans the creator of the Rocket Mass Heater RMH, planned that RMHs would be used mostly in 3rd world countries out of what could be scrounged-up.
Re-using old house bricks, and trying and discarding steel heat risers HAVE brought us to a better understanding of the proper Anatomy and Physiology of the Rocket.

Now light weight fire brick line our Feed Tube, Burn Tunnel, and generally make our Heat Riser, with ~100,000~ RMHs built word wide, most of them have been built with
his book, Rocket Mass Heaters $15.00 downloaded copy to your computer, from 'rocketstoves.com' make as many copies as you need !

There is STILL no other book in any language with more rocket stove family information! Of all of the First time builds, 95% of them were made (that Worked) following
' The Book,' again, for First time builders I can not recommend this book too highly ! And I don't know the man, nor do I get a nickel for recommending 'The Book' !

Please be aware, we are talking about three grades of Brick, #1) light weight fire brick, 28-30 ounces each, #2) 100 year old common red to red orange masons or house
brick, and #3) the heavy at 7#s each fire brick for lining Foundries- our LAST Choice if we are lucky, basically I would only take #3 the heavy brick if it was given to me !

For the good of the Craft, think like fire, flow like a gas, Don't be a marshmallow! As always, questions and comments, are solicited and Welcome, PYRO - Logically Big AL!

Jerry, remember that in a square, gases have a lower velocity, down to stalling in the corners. So the CSA of a square isn't as big as it seems to be. It all has to do with the boundary layer.

May be if Peter pops around, he'll give the numbers and explain better.

Jerry Ward & 'the Pcloud' :Our friend 'Max' must have been in a hurry, He could have added much more! Irregardless of shape we are dealing with a condition called Laminar flow.
Basically, this simply means that the Hottest gases flow through the very center, moving at the highest speeds. This progressively scales down to where the coolest gases are
'stationary against the Boundary Layer' of the surface of the structure that our Liquid, Gas, or Plasma flows past, within, or through !

This boundary layer could actually be called the Laminar no-flow layer. Also in the case of flowing a gas through a pipe the increased turbulence of a square will scrub against the
'boundry layer' at all bends, and it can even flow backwards for short sections especially at bends and curves!

This is a common experience in paddling against a rivers current, where skilled paddlers often change sides in a stream to paddle in 'slack water' or a counter flowing surface stream
at or near bends in the river! As "max'' said there are Boundary Layers of no flow, and in special conditions, even reverse flow in pipes, this introduction of turbulence produces two
things, Heat Energy, and vibrational energy as noise (wasted energy-but the source of our rockets roar, counter-intuitivly a quite RmH may be successfully generating more heat, with
less lost to vibrational energy ! For the good of the Craft !

Jerry I hope this is timely for you and helps ! BIG AL !

So what size square rocket core is recomended for a 6" and 8" chimney?

Jerry Ward wrote:So what size square rocket core is recomended for a 6" and 8" chimney?

Well, what is that chimney?

6? 8? or 6x8?

Round? Square? Steel tubing, Insulated? Bricks? Stones?

Prety sure that with a 8 round chimney, you can make a 8 square J tube work.

It also depends on your run of horizontal pipe.

I'm running a 6 batchbox, with may be 9m of pipe horizontaly, a reduction to 4 inch pipe on 1m 60, to go through the wall. There's a 2m vertical in between two row of horizontal. Three elbows, one semi elbow in the wall. And a brick chimney on the outside about 4m tall, against a wall and not going past the eave. Which has a 8x6 section. And this whole contraption draws. So only experiments will tell what works and what doesn't.

Sorry about the brevity of my last post, posting from my iphone tends to do this.

I have two paths I'm going down. I have a 6" chimney in my house that goes all the way down to the basement where I have a wood stove. The basement is a 9' high walk out and the chimney is 30' high going up through the middle of the house. I want to get to the point that I have a RMH in my basement. SWMBO will only allow burning wood in the basement, so that is the only option for the RMH. Plus I have less of an issue of support because this area has an extra thick slab. The 6" chimney is a hard requirement so what cross section of square j-tube burner/heat riser should I build? The cross section of a 6" pipe is just over 28 square inches and an exact cross section matching would be 5.3". If square doesn't flow as well should I move up to 5-1/2" square? I understand the length of duct that I route through the thermal mass is up for debate as I have to push the exhaust up a 30' of chimney pipe. However I need to know what size burn tunnel to aim for.

My second path is I want to build a system for a pole barn/workshop that hasn't been built yet. For this second application I have flexibility but am thinking about an 8" system as I will want heat quickly, bordering on just a rocket stove with limited thermal mass. The cross section of an 8" chimney is just over 50 sq in, so what size burn tunnel should I build? 7" square is 49 sq in, which is a bit under the chimney pipe. However if square flows less than round, should I plan for an 8" square burn tunnel?

Thanks,
Jerry

For the bassement rocket, bassement rockets are doomed. Who will ever go back every 1/4 of an hour to look after the fire? Even with a batch rocket, i would be dubious.

For the worksop heater, go to Donkey32 and search for the green machine.

Jerry Ward : In spite of my poorly hid loathing for All the crap on You tube I am sending you to a great channel, goto> www.youtube.com/user/villagevideoorg then
scroll down to Rocket Mass Heater Scenes and click on that! You should watch the whole thing but please watch the '' preparing your house (for your RMH), 1 of the
first 4? You need to listen closely to the part about Stack Effect!

This is your #1 problem in dealing with having a Rocket in your Basement, and though not clearly mentioned in the video clip, you can have smoke back problems any time
a clothes drier is running, or the Fan in the range hood, or the exhaust fan in your Bathroom !

You will have to tighten up your house, and start from the top and work down to the Basement !

Here is where I drop the big one, Any time that you, or anyone else tries to place your Rocket Mass Heater RMH, in an isolated or remote location and not in the very heart
of the home, Your RMH ends up serving you as well as you serve it, ideally your rocket should be placed within easy reach and certainly earshot of where you spend most
of your time, otherwise instead of being there for your pleasure, it becomes an interruption and a quickly burdensome chore to get up, switch on more lights go down cellar
and feed the damn Rocket, again, ether you move yourself and your activities to your Rockets place and bring your activities with you, or you will start making Excuses to
not build a fire !

We often say about potty training a baby that first the Parents get trained, and then the Baby, Constantly checking and consistency become an easy task, when 'your baby'
is right there at your elbow, With the RMH, you listen for the throaty roar of the Rockets Happy House Dragon, and glance at the Thermometer, dropping in one more piece
of wood on your way by.

If your baby was in a room distant from you, so that Training your baby was train the Parents to Learn to check on the baby in a timely manner, this small slip in good
parenting will quickly become a messy and stinky situation, and who wants to leave a working fire in a remote part of the house?

In your case, if you are planning on having a work shop and want a modified RMH that can more quickly come up to Temperature faster, we can much more easily work with
you and make it happen ! This would actually make for a Better First Build. This is your decision to make, but I ask you to consider it as trying to satisfy yourself, local build
-ing Codes and a future House Dragon will be a tuff nut to crack ! For the good of the Craft ! Big AL

The workshop will probably not be built until 2015 or maybe even 2016.

My house is new construction built out of SIPs so it is extremely airtight. I have make-up air going to the furnace room in the basement and another make up air duct going to the kitchen for the range hood. Also going in is a heat recovery ventilator which will supply fresh air to the area the wood stove is in currently (the potential spot for a RMH) and into the laundry room. While I understand the location is sub-optional for the upstairs, the basement is a family room of sorts. It is a walk-out and will have a TV and the computer(s) and a great view out into the woods, so we will be spending time in the basement.

Which brings me back to my questions, what size square burn tunnel and heat riser should I plan for a 6" and 8" chimney? Learning how to build one outside I want to try for the size burn tunnels I will need if/when I build something in my house or shop.

Jerry Ward : you make my work easy for me, Of the three component pieces, Feed Tube, Burn tunnel and Heat Riser the burn tunnel will always have a little wood /fly ash
in it rounding the lower corners slightly, If you plan your build for that as it is insulation, and protects the floor of bricks from chipping and spalling, You can easily exceed the
Cross sectional areas by 10%, 31 sq. inches, the other Two parts will not be as affected and need no fudge factor, so a 6''system= 31 sq. inches, an 8'' system 50 sq. inches,
but that would be for a system that is matched to its owner and the owner matched to the System.

Some where within two feet of my chair, I have a book Houses are designed by Architects and built by Gorrilas the S.I.Ps panels are great if they are properly install
-ed by a trained crew that has worked together before and are closely supervised ! I have my eye on Clay polymer aerogel in mylar bags ! No one is installing them in my
area !

Speaking of books, of the~100,000~ Rocket Mass Heaters build around the world since Ianto Evens created the concept, plans, and practical application, Most of the RMHs
were made following 'The book' Rocket Mass Heaters and 95 % of the first time Builds (that Worked )were made following 'The Book". There is STILL no other
book in any language, with more Rocket Stove family information!

This is where I recommend going to Rocketstoves.com to download your PDF Copy $15., print as many copies as you need ever, and you will have the quick under-
standing of the Vocabulary and the Geometries ( 3rd or 4th grade math) internal plumbing of the RMHs, that and 24 / 7 help from your fellow members here at Permies.com
should quickly solve any problems

A word about the Cob benches unique 'handling of water vapor', First as the temperature of the hot exhaust gases falls below 212*F the water vapor condenses and we gain
almost all of the Latent Heat of Evaporation, and the Cob stores some of it within itself, It is very common to seal the top of the Cob Thermal Mass Bench against accidental
spills but if the sides are not sealed,you will have a daily fluctuation of water vapor as the Cob absorbs on High humidity and releases on low humidity days, this will work to
reduce the work load on your H.R.V. an its sensors !

You have convinced me, I am sure that over time you will find that in Every way your Rocket and its Happy house Dragon will become the heart of the home, which is what
Hearth originally meant, not just an Architectural term !

Finally in our special 'booster' way we have bee building up the story of flames burning sideways and horizontal chimneys of 40', and it is true, I just want to leave you with a
simple phrase 'When the barrel goes on the Vertical chimney goes up' ! You are now by self-profession a Rocketeer ! For the Good of the Craft Big AL

Think like Fire, Flow like a Gas. Don't be the Marshmallow ! As always, your questions and Comments are solicited and are welcome PYRO- Logically BIG AL !