rocket workshops / innovators gathering / September 2014

Glyn Tutt : I will try to give you MY answers kinda in order from the second paragraph but 1st -a little of my interpretation of the History of the Rocket Mass
Heater RMH

When Ianto Evans modified the earlier Rocket Cook Stove into what would become the RMH he sought an area on the west coast with a stable Mediterranean
Climate. In fact he succeeded too well, even finding a micro climate with very stabile wind directions during the heating season !

Further, most of his houses were only one story cob houses sitting on the land -looking like Giant puffballs or mushroom buttons ! In these ideal conditions
he was able to build RMHs to have the incredible ability to draw 50' through a horizontal chimney and was very successful at that location of eliminating the
need for a final Vertical Chimney (!) -with repeatable results !

This then is the gold standard that All RMHs finally get measured against.

In more common practice The RMH like All other Hydrocarbon burning heaters need 1) a final vertical chimney, 2) taller by at least 4' that the nearest object
bigger than a TV antenna, 3) always located on the Lee side of the house .

Unfortunately, for most of the N. Americas a steady unchanging wind from one direction only within a Normal Heating Season is unknown ! There are scores
of very healthy businesses making and selling Storm Hoods, Directional, Stove Pipe ends and Masonry Caps, and mostly as a last resort in-line Exhaust fans!

When you add in the fact that All RMHs are D.I.Y. built with the possibility of errors in construction (and use) The Need to create a customizable ''Draft aid /
modifier* is worth exploring especially with the magnitude of stellar talent soon to be gathered at the labs !

Oh Yes ! It must also be remembered a MAJOR Goal is to ensure that any improvements can indeed be used off of the Grid ! And as always seems to
be true -Simple IS always better !

This answers your 2nd paragraph, and also your comments on your wood fired boiler! Tho I would point out that most J-Tube RMHs do not separate a primary
and secondary burn or have true secondary air, there are some well made exceptions.

Under normal situations a RMH would rarely be considered hard to light and there are lots of ways to smooth the process for the exceptions mostly at ether end
of the core of the Heating Season ! (Steady winds prevailing !) Bypasses Exist, but seemingly are rarely used, perhaps that is an over site !

In common practice the 'size' of the Feed Tube is regulated by placing a brick over part of its top, this is adjusted mostly by a practiced operator easily and by
ear !

This was my perhaps over-long-winded- attempt to clarify some minutia, if I have erred the error is my own, there is always a certain conceit in reporting on
facts when you are not personally there ! For the good of the crafts! I hope this was timely, useful and clear !

Think like Fire! Flow like a Gas! Don't be the Marshmallow! as always, your comments and questions are solicited and Welcome ! Big AL

* the terms draft control and draft corrector are already used to describe much different equipment A.L.

Was asked to post this idea here by Allen Lumley... Original post at https://permies.com/t/39642/rocket-stoves/Improving-longevity-riser

I hope this proves useful.

Firstly, Thank you all for having and being here in this forum of innovation. It warms my heart to connect with folks that truly think outside the box.

I have been researching for some time and feel I have a good grasp of the concepts and methods, sufficient to take some "next steps" in the basic engineering of these stoves. I can see some of the inherent issues associated with thermal gradients and stresses in the commonly used materials and being a Toolmaker, I have fairly good skills in troubleshooting designs of all sorts.
It appears that the primary area of premature stove failure is in the materials used for the extreme heat areas of the stove, specifically the lower portion of the riser tube. After some consideration and noodling about this issue, I have an idea that I would like to pass on to the group for feedback and possible testing.

It is clear that a refractory material is necessary to line the riser in order for it to last for the maximum time. Common materials used in the research I have seen are fire brick and pearlite/clay mixes, both with inherent issues. The brick option takes up a lot of space and is difficult to insulate and the pearlite/clay mix requires a form to maintain integrity of structure and that form, typically steel tube, will go away after a few seasons.
So, I have thought of a potential solution.
I have found castable refractory materials that, although a bit pricey, will handle the 3000 degrees and survive the heating/cooling expansion/contraction cycles quite well. My method to use these is this.

Roll out a thin slab of this castable material like rolling out a pie crust, with wire mesh embedded in it for stability (I suppose one could use any adjunct commonly in use if one has trouble with wire mesh), wrap this "crust" around a disposable form or even the commonly used stovepipe, then wrap that in rockwool with a split stovepipe covering to hold it all together. This should provide a riser life that far exceeds the common steel riser, far greater insulation and performance than firebrick and with careful packaging, should be able to be shipped or moved easily without damage.
The choice of castable refractory material will need to have some variability in its mixing to create a fairly thick consistency, like pie dough, but I don't see this as a significant issue.

If one were to roll out the "dough" on a fireproof cloth type material, the rolling around the form will be rather easy... If in doubt, ask Gramma how she keeps the pie dough from sticking to the breadboard... She will have some great ideas that can be adapted.

Curing of the "dough" may require it be open to the air for a time, but I don't see this as a significant issue provided the stability adjunct (wire mesh, hair, straw, whatever) and the cloth you roll on can support the weight without distorting or allowing the "dough" to flow or move.

I would like to test this myself but personal issues prevent me from experimentation at this time.

So I put this to the community for perusal, disassembly and debate in the hopes that one of you intrepid pioneers have or can obtain the materials necessary to further the research.

Thank you for your time.
Peace...
John.

Just one photo for now: the basic cob rocket. So far.

So, it looked like the heat riser wasn't dead center of the barrel in the contraction pictures (in "Kristie's weeklyish photos"). Is there a story there?

The innovators have discussed creating a rocket stove set up that could either scald harvested pigs or be used as a hot tub. Is that creepy?

More great R M H build photos in Kristie's thread (page 26). Here's one:

I would love to learn how to use a rocket stove to heat water for hot tub! I'd love to have a hot tub, but the typical ones aren't very appealing, with all the energy use and toxic chemicals used.

Jocelyn Campbell wrote:The innovators have discussed creating a rocket stove set up that could either scald harvested pigs or be used as a hot tub

I was about to link something about a NZ tradition; the fire bath.
Heaps of fun, but requires balancing on a wide board or you burn your bum-'bathing as extreme sport' kind of thing

When I searched 'fire bath', what should be at the top but rocket stove fire bath

Leila Rich wrote:I was about to link something about a NZ tradition; the fire bath.
Heaps of fun, but requires balancing on a wide board or you burn your bum-'bathing as extreme sport' kind of thing

When I searched 'fire bath', what should be at the top but rocket stove fire bath

That does look fun! As well as potentially bum-scalding!

Rebecca Holman posted one of the pictures from that same link for the rocket stove fire bath out on my FaceBook page.



It look really cool (er, hot)!

Anybody in missoula wanna come out and wash dishes for the rest of the event? We could use two dishwashers. If interested, send email to jocelyn at richsoil.com

Here at the RMH innovators event things are really getting out of hand, one example is Matt, a man who has shown himself to be a die hard doer and utterly incapable of not-getting-things-done.

I'm a fanboy!
Seth
Your local larder.


P.S. If you wish you were here with us, there is an offer on the table for an excellent dishwasher, house cleaner to help us these last few days.

Here's a view that shows why the heat riser is off center of the lower barrel or manifold. You'll notice that the pipe joining the riser is slightly behind the riser. The reason that the manifold is moved back is so it connects with that pipe better. This shouldn't affect the secondary burn or flow of gasses. That's what I gathered from participating in the class. If I missed any other reasons I'd love to hear.
I had a great time and only regret not being able to stay for the innovators event. So many brilliant ideas. I can't wait to see what new goodies come from it.
Thanks for the great time and new friends.
Colin

Colon S. If past experience AND the 2nd edition of Ianto Evans 2nd eddition of Rocket mass heaters is to be believed, with the minimum spacing of 1.5''
between the top of the Heat Riser and The Inside top of the barrel for a 6''RMH system, And 2.0'' for the minimum spacing of the gap between the top of
the Heat Riser and the inside top of the Barrel -If the barrel is off set the narrowed side is always cooler and the wide side is always hotter !

I have some experience with 3 RMHs built to that pattern, and they do often appear to follow this rule! this is common to all 3 RMHs constructed with
minimum gaps between the H.R.s and the barrel !

I have zero experience with a larger H.R. to Barrel gap, but there is still a frequent referral to anecdotal evidence of a reversal in the heat patterns when a
Larger H.R. to Barrel gap AND an off-set barrel to H.R. placement are both used, your explanation of the greater area given to gas flow through the
transitional area is a fair description of what we are seeing, it does NOT address the basic issue, whether or not off-setting of the barrel continues to affect
the hot gases flow, and how it does so ! for the Good of the Crafts! Big AL.

allen lumley wrote:Colon S. If past experience AND the 2nd edition of Ianto Evans 2nd eddition of Rocket mass heaters is to be believed, with the minimum spacing of 1.5''
between the top of the Heat Riser and The Inside top of the barrel for a 6''RMH system, And 2.0'' for the minimum spacing of the gap between the top of
the Heat Riser and the inside top of the Barrel -If the barrel is off set the narrowed side is always cooler and the wide side is always hotter !

I have some experience with 3 RMHs built to that pattern, and they do often appear to follow this rule! this is common to all 3 RMHs constructed with
minimum gaps between the H.R.s and the barrel !

I have zero experience with a larger H.R. to Barrel gap, but there is still a frequent referral to anecdotal evidence of a reversal in the heat patterns when a
Larger H.R. to Barrel gap AND an off-set barrel to H.R. placement are both used, your explanation of the greater area given to gas flow through the
transitional area is a fair description of what we are seeing, it does NOT address the basic issue, whether or not off-setting of the barrel continues to affect
the hot gases flow, and how it does so ! for the Good of the Crafts! Big AL.

Hi Allen,

If I remember correctly, Ernie and Erica were going for a 2 inch gap between the top of the heat riser and the top of the inside of the barrel. I believe that if the barrel was hotter in back then that would give more heat to the chimney and therefore increasing the vertical push of exhaust up thru the chimney. I'm still learning, so that is only a guess.

Colin

The 8" batch box system...

More pictures of the RMH circle with some plaster work

Pictures from the afternoon

More pics from thursday

Looks great guys!!!

I'd like to hear what the batch heater is for, or what it does differently. I can see that the circular bench is a way for a group of folks to sit around in a comfy circle outside at night, but I can't discern the idea that led to the batch heater.

Julia Winter wrote:I'd like to hear what the batch heater is for, or what it does differently. I can see that the circular bench is a way for a group of folks to sit around in a comfy circle outside at night, but I can't discern the idea that led to the batch heater.

Mo powah!


http://donkey32.proboards.com/thread/511/adventures-horizontal-feed

Julia Winter : Remember the phrase ''schools out for summer''? Well its September, and Paul W.s got a 'gather' for all the pyros!

You can always tell the Age of the Boys, by the size of their Toys ! !!! ( Color me jealous! !!!) Pyro-magically there in spirit ! Big AL

Notes for next year:

92) we need a kitchen commander that will provide a budget before the event is announced, and then a revised budget about a month before the event. The kitchen commander needs to take care of all food acquisition, food prep, serving and all food cleanup. I guess the important thing is that all this stuff is so well executed by the kitchen commander, that I don't need to be called in to solve problems.

92.1) This budget needs to include the costs in washing dishes. Even though everybody washed their own plate, it would take several people many hours to clean up in the kitchen afterward. I would think that by the time a meal is served, nearly all of the dishes for cooking would be done. And the post-meal cleanup would be dominantly putting leftovers away and cleaning the serving dishes. If we need a full time assistant, we need to know that before the workshop is announced so we can budget for it. Maybe we can arrange something where if a person assists during one event, they can get a ticket to a future event.

92.2) The dish cleaning station needs a lot of upgrade. Let's have something a bit nicer. Maybe the dish washing bins could be wooden (I think that would be a really cool thing - build wtih dry wood and as the wood absorbs water it expands and becomes water tight)? And maybe something covered in case it rains. And once in a while I felt like I got my dishes plenty clean and put away, but now I wanted to wash my hands a bit - so that would be nice.

92.3) The KC will have somebody do a pass through every hour or so through the day and cleaning up through the night. And somebody will do a cleanup an hour or two before breakfast.

93) I think we need to collect heaps and heaps of materials through the year before the next event. Bricks, duct, metal, stove glass ....

94) A few tools that would be good for next year: a plasma cutter; a metal band saw;

95) We need at least one person that will be "the shop commander" that will make sure that the innovators have the tools they need and, when not being used, the tools are maintained and put back. That person will also make sure that all job sites are tidy at the end of the day.

What else?

[youtube] http://youtu.be/R3ulirhiDVM

Here is some video of the first lighting of the RMH. We had a little difficulty getting good airflow thru the system because of the the hot air temperature outside the building and the cool and wet cob and bricks. These conditions won't be present on a day when you would normally light the heater. You want to light the heater while it is still wet to expand the pipe a little before it sets to reduce any cracking.

I've embedded that video for you.

Burra Maluca wrote:I've embedded that video for you.

Thanks Burra, I am still trying to figure this video thing out

Thanks everybody, for posting pictures, and for being part of a great workshop.

As for the batch box - there are two main points:
1) being able to load wood and close a door, which some people find convenient. A half-batch or a full batch of wood takes about the same time, 45 to 50 minutes, so it's easy to come back and load it again while doing something else in between. (Not recommending it burn unattended, but it might be easier for some people to run who are accustomed to a door-type loading system).
This door and box also opens the possibility of testing the stoves under current protocols for masonry heaters in the USA, though I doubt that was Peter's priority.
and 2) being able to load more wood for a larger heat output from the same chimney size.
Because it's built by Peter, the batch box also has clever proportions that give it some of the lowest possible emissions. On a scale from 0 to 4000, where 4000 is clearly visible smoke and 100-500 is considered pretty darn good by any modern stove-maker, this batch box was scoring an awesome 0-20 on carbon monoxide emissions throughout its main burn cycle. (Whether there were spikes at start and cool-down I haven't checked, but the line was pretty flat when I glanced at it around the 35-minute mark of one of the test burns.)

The big double-barrel was just for testing purposes, in lieue of a larger masonry bell or bench. Peter calculated the surface area that would be needed to capture and use that heat. For the big shop space, it's a quick radiant heater that can warm a lot of space and/or people in a hurry.

We had such a wonderful time playing with everyone who came, and especially with our distinguished colleagues from far away.

Tim's three-headed monster did some good water heating after he left. Rick said the tank supported a steady trickle of warm water for several minutes, even after the fire had been out for perhaps half an hour to an hour.

Yours,
Erica W

Here's a link where Jeyte Timmerman (travelled all the way from the Netherlands w/ Peter van den Berg) uploaded several images daily:

Jetye's Flickr pics

I gave everybody three days off after the event. So today we're gonna start cleaning up.

I was talking with Ernie and Erica a bit about what we might do next year.

This year's five day innovator's event was just right. We are going to invite back the innovators and maybe add two more.

Rather than have a standard rocket mass heater workshop, we were thinking it might be good to have a different kind of innovators event. So, maybe a three day innovator's event (wednesday through friday) that is for people that want to do "show and tell" or "build and tell" for the innovators to see on the following monday. The idea is that the first event could have an influence on the second event. Plus, this year, several of the innovators showed up several days early and started making cool stuff - and that was where a lot of the super-creative idea exchange happened.

This year, some of the people that live here got really wore out by the end of the event - so the idea of having a weekend between the two events will help to give some rest. Plus Ernie and Erica pointed out that some folks really need to drink in Missoula while they are in the area. And that would be a good time for tours and the like to see the rest of what we have going on here.

Another thing is that I think these events should be slid back to october a bit. We hit a warm spell in the middle of the workshop and that turned out to be a problem when trying to fire up a rocket mass heater.

So, tentatively, the three day event would be october 7-9 2015, and the five day event would be october 12-16 2015.

This is just a rough idea. I'm open to suggestions.

I think we need to start putting together a list of materials for next year.

We had a small mountain of barrels and I'm pretty sure we could have used a few more this year.

How many barrels did we start with this year? Whatever it is, we should probably triple that for next year. And maybe build up an inventory of lots of different sizes.

It seems we went through a lot of fire brick. And the red brick with holes. I think we need lots and lots of all sorts of clay brick (not the cement stuff).

I went ahead and embedded some of those pictures from that link Jesse. I hope that is okay.

Yep that's great! Jeyte asked that they be shared.

Just posted: Results of the batch box thingy.

What was Tim's innovation called again? Pocket Locket Rocket?

paul wheaton wrote:I think we need to start putting together a list of materials for next year.

We had a small mountain of barrels and I'm pretty sure we could have used a few more this year.

How many barrels did we start with this year? Whatever it is, we should probably triple that for next year. And maybe build up an inventory of lots of different sizes.

It seems we went through a lot of fire brick. And the red brick with holes. I think we need lots and lots of all sorts of clay brick (not the cement stuff).

I'm just some guy, so take this with a grain or two of rock salt.


It seems like each innovator could have materials for two or three RMH to be built and working at any given time. This would allow variations to be tested and reviewed side by side.

I think there were 12 barrels or so used. Another few barrels could have been used for bulk material storage (clay, slip, perlite / clay mix, etc.).

If the idea of using a standard bench equivalent of a few barrels with bricks in them catches on, a bunch of them prebuilt would be good.

Some pre burned out ceramic risers would help cycle time by avoiding a full burn in cycle on each new riser before good gas measurements can be taken.
Likewise some of the barrels could have their paint/epoxy burned off before the event so the innovators can focus on the interesting stuff.


I am a data nerd. More instrumentation. An IR camera would be awesome. Site specific things would be helpful though, local air temp, humidity, windspeed, etc. would be good.

Being able to measure duct air flow would be nice (though commercial solutions may be expensive).

Some method to measure the air tightness of a component could be useful. This could be as simple as putting a ducted fan over the feed tube and measuring the pressure differential between the inside of the feed tube and the stack output or using a exhaust fan to pull and check the differential between the end and the air inlets. Batch heaters would be harder because of the extra air input.

A contraption to help the first time cold start a rmh might be useful. E.g. A temperature rated exhaust fan attached to the far end of the stack maybe http://www.hvacquick.com/products/residential/Fans/Chimney-Fans-Draft-Inducers/Tjernlund-RT750H-RT1500H-Rooftop-Inducer, (or a cheaper some such).

More welding gloves, those were helpful.

Enough glass to build a glass walled (maybe just one side) RMH. (one can dream, can't one?) Or at least one or two pieces per innovator.

A gopro camera per innovator. Possibly glued to their heads.

Several yards of premixed cob without straw/ Thermal cob. Maybe some plasters and mortars as well. If not that, then plenty of precursors. Sifted sand and chopped straw, hydrated clay, etc.

More 5 gallon buckets... cuz' it seems there can never be enough. ( maybe 4-6 per innovator?)


water fittings / tanks... sized like a hog scolder or an artificial hot springs. cuz' if stuff is just laying around and out, someone may put it together.


Same for the rocket forge/smelter parts / tools. Tongs, anvil, a hammer or two, a crucible, molding materials, and some stock for use in anything that happens to be produced. If it could also be used as a ( big chunks of aluminum (or cans), iron, maybe glass, brass?).


Probably more that I'm forgetting.

About 20 barrels were used during this event. I think next year we should try to have 60 barrels, including a few different sizes.

IR camera: link?

I think a collection of time lapse cameras would probably be wise.

I think having a rocket forge here before the innovators event begins would be way cool. And I would think we would find lots of uses for it.

Two things that my brother has been pushing for, and maybe if we have a successful kickstarter: a plasma cutter and a metal bandsaw.

Tom Rutledge wrote:

I am a data nerd.

Hardest working data nerd I've ever met. Total badass is more like it.



The Testo 330 will measure atmospheric pressure inside and outside, so could be used for some of that data. If Tom wasn't completely covered in mud the whole time and we thought of it ahead of time we could have crowned him King Data Nerd and given him the Testo for the week and recorded a lot more data in real time as we built stuff.

Tom Rutledge wrote:
water fittings / tanks... sized like a hog scolder or an artificial hot springs. cuz' if stuff is just laying around and out, someone may put it together.

Artificial hot springs.

Yes.

We do need something for scalding pigs. And it does seem like we could use the same thing as some sort of hot tub.

A friend of mine is working on a RMH using a metal casing from a jet engine filled with water as the mass. Don't know how he got his hands on that though