rocket stove and butt warmer

Len wrote:
I think if the RMS heater was treated as a masonry heater with a separate core and facing... the core is the part that needs the most engineering, so if a standard core could be designed that can be standards approved (CSA in Canada, UL or EPA in the US) then the facing could be much easier to deal with... it would still have to be fireproof... but cob should be possible.

Well there we have a possible money maker.
Anyone willing to put the time and effort into engineering a standardized core??
I just don't have the skills or time for such a thing.

Hi...I'm new to this forum...but we are starting to put our greenhouse "together" tomorrow (couldn't convince my husband to do the oehler one)...am very interested in doing the rocket stove to heat it for winter.  I've watched about 20 videos and none of them give enough specifics.  Would the book be the best way to understand this for 'greenhouse' application?  I'm doing it for "Aquaponics" and would love to keep it warm! Thanks...

With all the talk about how things work... I thought this little quote might apply. This is from the MHA tech notes section and is part of an email posted by Alex Chernov, a Mason (the kind that works with bricks).

I completely agree with you that stacking and fuelling have enormous impact on emissions. However, I have come to realize that it is extremely difficult to teach the operator here, in North America - I find that quite a few of my customers don't even read the manual I supply them with... From now on I am giving my clients a Client Acknowledgement Form to sign. They are signing that they have received the manual and instructions and understand importance of following them. I hope it will help somewhat, but I am afraid not that much.
I have come from a country with strong traditions in masonry heaters, country where people are used to follow certain firing routine and perceive it as the norm. And I used to think the same way. However, it is very different here. Too many people apply open fireplace firing techniques to masonry heaters either conscientiously or not simply because there is no tradition for masonry heaters. It takes centuries and generations to develop right attitude towards wood fire and firing own heating fireplace. It is very difficult to change.

Perhaps one of the problems we have in North America, is that the cultural background of many of us comes from relatively warm climates.... compared to Russia... Britain, France, and Spain (for example) are warm. 100 years or so ago there were still public buildings in Britain that were heated with an open fire in the centre of the room!

So the "I've used a fireplace/caste iron stove since I was a kid, I know what I'm doing" way of thinking, is not going to work with any kind of mass heater including a RMH. Before building one remember you will have to relearn fire making and keeping. You will want to make an instruction manual for other family members and perhaps keep notes on what works best. These things might include the weight of fuel for one burn, how long the mass stays warm, how long it takes from first lighting the heater till things feel comfortable.... when the heater is cold or still warm... depending on the outside temperature, etc. If you add bypass dampers for easier starting or have to open a window or other opening to supply air, things get more complex. The advantages of a mass heater come with a learning curve. Another advantage of the RMH over the masonry heater is that there is less temptation to have a "nice fire" in the summer evening as there is not much of a fire to see

has there been anymore work done with the stove in the wooden box?

Instead of butt warmer, I'm looking for a greenhouse warmer.  Can anyone please help me with this idea:

Build a brick rocket stove in one corner of the greenhouse. (10x24 greenhouse) Exhaust stove pipe comes out and goes down into a ditch, (or underground) the length of the greenhouse (say, close to the long south wall).  MAIN QUESTION: Will  it draft if I put it in an 8" pipe going down into the ground in a 15" deep ditch for a 20' run before coming up out of the ground and up and out the "chimney" at the other end?  Also, if I use 8" pipe can my ditch be less than 15"?

Fill ditch covering pipe with mortar up til level with the ground.  Lay 55 gallon steel drums on their side, end to end, in/on mortar ditch for good contact with barrel sides with the mortar.  I will then fill the barrels with water for my thermal mass being heated by the warm mortar once I've built a fire in the heater at night.  Hoping this will cause the barrels to release heat all night long.  (I understand for heating purpose thermal mass of water is 4x that of cobb or mortar.)

I will put these barrels UNDER my raised growbeds that will line the south wall. (as my GH is only 10 ft wide)  I will also have growbeds on the north wall.  This entire design could be moved to north wall, doesnt really matter which wall rocket system is installed....  Whatdya think?  Thanks!

Appropedia has a nice page on RMHs, summarizing advantages and design principles. The author of the page also poses some questions (like:How long does the stove top last given the amount of heat being put there? Is maintainence built into the standard design?) in case anybody would like to respond. Link: http://www.appropedia.org/Rocket_stove_mass_heater

Is it OK if my stove pipe runs "uphill" slightly?  Or will the "water" that is supposed to exit at the end (along with the CO2) run backwards downhill back toward the stove?  Getting ready to put this in my new greenhouse and the floor isn't level.

If water barrels sit very "near" the stove pipe will the water in the steel drum get heated by being only an inch from the pipe, or does it have to be encased in mortar or cob?

livinontop wrote:
Is it OK if my stove pipe runs "uphill" slightly?  Or will the "water" that is supposed to exit at the end (along with the CO2) run backwards downhill back toward the stove?  Getting ready to put this in my new greenhouse and the floor isn't level.

If water barrels sit very "near" the stove pipe will the water in the steel drum get heated by being only an inch from the pipe, or does it have to be encased in mortar or cob?

I ran my pipe slightly downhill until the final turn up the chimney.  Works well.  I have a stove in my green house.  If you go back a page or two I posted some videos in this thread.

I am probably finished running the stove for the season.  Still, the bench absorbs a lot of heat during the day and stays around 70 F most of the time.  It does not really keep the air that warm when I'm not using it.  But I use the bench for my seed starting soil blocks, and the bench keeps those at a nice 70 F.  My starts love it.

Remember for the most part, soil temp is much more important than air temp when starting seeds.

Thanks for reply. After re-reading "the book" I too think I'll run my pipe "downhill". I'm not 'starting' plants in this greenhouse. I'm using it for "aquaponics".....and am going to put (waterfilled) 55gallon drums on their sides on my stovepipe, hoping to heat the water in them for a great thermal mass to heat the greenhouse throughout the night.

I know I won't be getting it real warm doing this, but it should raise it a few degrees and keep it from freezing....I hope.  Thanks again for replying!

Here is Paul's latest podcast, interviewing Ernie and Erica on Rocket Mass Heaters: http://www.richsoil.com/permaculture/182-rocket-mass-heaters-permaculture-podcast-019/
'Tis worth a listen.

I am thinking of makeing one of these and was wondering if you can make a form and just use concrete instead of cob for the bench and use off the shelf selkirk chimney for the riser.

For those who are interested..... here is a RMH made of masonry. No steel, no cob.
http://mha-net.org/docs/v8n2/wildac11h.htm

It was built quick as a demo and then knocked down at the end of the week and so the bench is rather small. It also goes up a chimney and so the exit temp must warmer to make that happen.

I was wondering if anyone had any ideals for powering a fan - not using electricity?

I was thinking of using a long-ish lever or bar to compress a spring of some sort.  That would then relax over a period of two or three minutes - and provide the energy to spin something creating the breeze.  The breeze would be especially iseful when startig the stove to help get the draft going, or periodically stoke up the fire is using less than ideal wood, etc.

It would fit in well with the idea of "tending" the the rocket... feed it a few sticks, crank the lever... etc.

I was also thinking of a weight being pulled down by gravity - i'd love to hear of any ideas involving a short action that results in two the there minutes of "fanning".

Scott911 wrote:
I was wondering if anyone had any ideals for powering a fan - not using electricity?
...
I was also thinking of a weight being pulled down by gravity - i'd love to hear of any ideas involving a short action that results in two the there minutes of "fanning".

There was such a device for use as a rotisserie (possibly called a "clockwork jack"?) Using weights and pulleys. i would think it kept the  bird turning for more than just a few minutes as it takes us about an hour to cook a small (2-3 lb) bird. However it would have been turning much slower than a fan.... unless the fan is quite large   I have only the picture on the front of the book "The Forgotten Art of Building and Using a Brick Bake Oven". It doesn't show much.

Something that might work though, is a good sized bellows with no spring inside, that you would put a weight on. The size of the bellows, the size of the air outlet and the size of the weight would determine how long it kept blowing and how much air it moved over time.

Really, the idea of a RMH is that it does it's own blowing. You shouldn't have to use such a device at all, but if you did it would only be for the first minute or so. The hand crank units a black smith uses would work just fine for that. The riser just has to be warmer than the feed tube and its off. At least the pile of bricks I have played with seems to draw in under a minute with just some newspaper.

Scott911 wrote:
I was thinking of using a long-ish lever or bar to compress a spring of some sort.  That would then relax over a period of two or three minutes - and provide the energy to spin something creating the breeze.  The breeze would be especially iseful when startig the stove to help get the draft going, or periodically stoke up the fire is using less than ideal wood, etc.

This makes me think of how salad spinners work...if you could do that with fan blades...
or maybe a bicycle wheel with fan blades?

Due to the nature of a rocket stove a fan isn't really a necessity.  Even relatively crude ones such as the big PW's 1 hour portable set-up start up lickity split.  You might get a bit of minor backdraft but it should only be a few moments then the "rocket takes over to create the draft.

Hi Paul,

I hope the rain you're getting isn't too dreadful.  We are starting to get back to normal here in NW Arkansas after about 30" in the past two months. 

I heard/saw the interview of you at the SocioCapitalist with Luke Miller Callahan (I think I have those names right) and if I remember correctly you stated that a rocket mass stove heater you had built substituted pebbles inside of a plywood box for the mass, instead of cob.

If I've got this right, would you happen to have any pictures or plans for such.  I've searche many of the YouTube videos and did not see this.  Thanks.

John.

John Fritz wrote:
if I remember correctly you stated that a rocket mass stove heater you had built substituted pebbles inside of a plywood box for the mass, instead of cob.

If I've got this right, would you happen to have any pictures or plans for such.  I've searche many of the YouTube videos and did not see this.  Thanks.

There is a whole thread on it:
https://permies.com/permaculture-forums/2558_0/alternative-energy/portable-rocket-mass-heater

There are no plans, but the pictures/videos are clear enough that they should not be needed.

I'm curious what other rocket mass heater folks think of this: www.greenoptimistic.com/2008/11/06/candle-room-heater

Suzy_Bean wrote:
I'm curious what other rocket mass heater folks think of this: www.greenoptimistic.com/2008/11/06/candle-room-heater

A candle puts out the same BTUs not matter what is sitting above it. The flower pots do absorb heat that would normally just head for the ceiling and radiate it at floor (or whatever) level where it would be more useful. As the mass is quite low and allows lots of air flow, the storage effect is going to be low... that is, after the candle goes out the heat in the radiator will go quick. There will be CO and CO2 and other burning artefacts floating around the room. Venting those may negate any gains. There is not much to them... buy three pots (or scrounge them) put a bolt through the centre and use an old coat hanger bent to hold it over a candle.... see how you like it.... then buy it if you want.

The most interesting words in the writeup are at the bottom:

"It is definitely an excellent gift for a candle loving, green optimistic friend."

Note the word "optimistic".

Thanks Len.

A rocket mass heater combustion chamber is mounted on top of a conventional wood stove. 

Ernie Wisner has built over 700 rocket mass heaters and this is his third hybrid.  In three minutes he covers a lot of detail about the efficiencies of conventional wood stoves, rocket mass heaters and hybrids.

i used to own one of those little stoves.... not as a rocket stove tho 

it worked fairly well  but the load(fuel) chamber was way to small

so i was a pain in the ASS

when i moved......... i left it behind

Hey Y'all,

Around here everything is very steep, so most folks have to build houses with very small individual floors a few floors tall. often each level has access to the ground. I am wondering what the collective wisdom thinks about having a traditional stove on the first (bottom) level with a flue which traveled straight up to a heat riser/reburn barrel on the second floor. You could then do what you wish with the exhaust heat. (greenhouse, bench..whatever) Perhaps the top of the reburn barrel could be a cooking surface, or at least return moisture to the cool air with a tea kettle. In this way the bottom floor can be more of a mud room / utility space and the real heat output would be located in the higher use living space.

TCel wrote:
Hey Y'all,

Around here everything is very steep, so most folks have to build houses with very small individual floors a few floors tall. often each level has access to the ground. I am wondering what the collective wisdom thinks about having a traditional stove on the first (bottom) level with a flue which traveled straight up to a heat riser/reburn barrel on the second floor.

The main problem would be retaining the heat for the distance from the fire to the reburn. I think the (tall) riser would have to be insulated all the way up... that being the case, the reburning would happen lower than you want. The question would then be... would the riser still push the gasses effectively? One way to find out... build one outside and try it.

Please be patient with a brand-new permie here:

I would like the ducting clarified by someone. Is the combustion chamber ductwork the same as the heating ductwork in the RMH?

Thanks for any answers!

Cheers,

Osa Johnson

osajohnson wrote:
I would like the ducting clarified by someone. Is the combustion chamber ductwork the same as the heating ductwork in the RMH?

Can be. the combustion chamber ducting must not be galvanised (heating) duct. Use painted wood stove duct... the cheap $6 for 2 or 3 foot stuff (may be cheaper per foot in longer lengths and most people use scrap or "pre-used") not the 3 wall stuff for going through wood holes in the roof/wall. Some people do use the galvanised pipe for the storage mass ducting because that is what they have on hand. However, the stove pipe is to be preferred. Over heated galvanised pipe gives off poisonous fumes.

I love the concept, and thank you for the videos etc as to how to build this!!  I am considering this, and also wrapping the ducting with copper hose to heat water that would be circulated through radiant flooring, the hot water heater, and out to the greenhouse via solar / photovoltaic driven pumps to maximize the heat capture...  Any thoughts, or experiences from those who've done it?

Wannaperm wrote:
I love the concept, and thank you for the videos etc as to how to build this!!  I am considering this, and also wrapping the ducting with copper hose to heat water that would be circulated through radiant flooring, the hot water heater, and out to the greenhouse via solar / photovoltaic driven pumps to maximize the heat capture...  Any thoughts, or experiences from those who've done it?

If you are an engineer and can sign off on the whole thing as safe it will save you this one simple safe step:

Simply heat the water in open kettle on top of the barrel or on something then pour the water into the underfloor system as needed.

The fourth picture at this site has a bench, and it it lined with wood. I was wondering if people thought this type of bench would work for a rocket mass heater. It looks nice to me, but would the wood be a problem? http://www.fotevikensmuseum.se/engelsk/art_english/e_art17bq.htm.

PermieFan wrote:
The fourth picture at this site has a bench, and it it lined with wood. I was wondering if people thought this type of bench would work for a rocket mass heater. It looks nice to me, but would the wood be a problem? http://www.fotevikensmuseum.se/engelsk/art_english/e_art17bq.htm.

Paul has built a RMH with a wood box around the mass bench. See the thread below:

https://permies.com/permaculture-forums/2558_0/alternative-energy/portable-rocket-mass-heater

There are pictures of it too. Because it is portable, I do not know if it is in continuous use or if it has had a good long burn. Try asking in that thread.

Why couldnt you essentially turn a gasification system into this same model for heating and the gases could then be used to run something like a generator. Just now learning. Great info. Thank you!

So, can you use regular duct or do you need Stove Pipe? I'm thinking of using 8" pipe because I listened to a podcast that said the 6" was too small. Is this truly true? Also, can someone tell me what sized barrel to use? I see 55 gallon barrels in some pics and teeny ones in others. I have looked around and the smaller barrels are very expensive. Is there any advice on where to find a good barrel? A specific industry that people call on when they need a metal barrel?

Thanks in advance for any help and sorry if these are el lamo questions.

So I really want a rocket mass heater in my living room and so does my wife but my wife is extremely against having an 55 gallon drum as the center piece of the living room. Would it be possible to build over the drum with something to hide it such as cob or perhaps a frame of some sort with say...tiles similar to a ceramic heater? Would covering/insulating the drum have any affect the performance of the heater?
Thanks
Daniel

Though Ya'll might be intrigued by this. I work part time at frito lay, and can get stale corn chips, they've been quite an aggressive fuel when thrown in my garage rocket mass heater, it's been up to 700 degrees in just a few minutes.

Sterling Morrow wrote:Though Ya'll might be intrigued by this. I work part time at frito lay, and can get stale corn chips, they've been quite an aggressive fuel when thrown in my garage rocket mass heater, it's been up to 700 degrees in just a few minutes.

wow. that's amazing.

I am thinking of building a rocket stove in my living room but I don´t like the idea of using metall. Does it work just as well with ceramic tubes and a ceramic cubical instead of the barril? Hugs Jason

Paul, the new pics on the RMH page are very good. Anyone with an open mind should get it. Some of us are not so open yes this includes me as often as not.

The more you know, the more you know you don't know..... One of the best things I learned in tech school.

Jason Baker wrote:I am thinking of building a rocket stove in my living room but I don´t like the idea of using metall. Does it work just as well with ceramic tubes and a ceramic cubical instead of the barril? Hugs Jason

Hi Jason,
The metal does help a lot with the updraft-downdraft thermisophon effect. Metal sheds heat faster than ceramic. The 'warm' exhaust in the barrel falls downward because it's colder than the 'hot' rising upward in the insulated 'heat riser' inside. If the barrel and heat riser get close to the same temperature, the hot exhaust can stagnate at the top of the barrel, and choke out the fire.

We did have decent results with 24" ceramic chimney-liner, but there's still the concern of air leaks. We would love to try some textured 'tile stove' tiles that might shed heat more like the heat-sinks on computers (think fins), plus have a broad mortar surface to reduce the chance of cracks and leaks in the mortar. A typical masonry heater uses double-layered masonry where the joints don't line up, and that double-layer would also tend to reduce the heat transfer. A good enough seal needs to prevent ALL air leaks. Air leaking into the stove can be as bad as smoke leaking out; a leaky siphon just doesn't work.

You could also consider doing a metal barrel, then adding a heat-shield type screen to give the heater more of a tile or ceramic aesthetic. Just allow enough air flow to cool the barrel.
We've only seen a few examples where the barrel was insulated, or cobbed in completely. These routinely have problems, compared to a barrel that's exposed or not more than 1/3 covered.

Yours,
Erica W

That post is over a year old. Interesting.