rocket stove and butt warmer

The air intake is with the sticks.

Although, I have to say, that I saw a picture of one where there was an air duct that went from the outside to the first fire chamber and then you could put a lid over the sticks.  I think that is an optimal approach.

I asked about this at the workshop and Ianto (the author of the book) said ...  well ...  I think his general message was that it wasn't worth the effort. 

There was a lot of talk about houses in sweden (or was it finland?) that did some similar stuff, but their house was completely open to the outdoors in the winter and the people were perfectly warm. 

Ianto and some of the other instructors talked about the error of living in a ziplock bag.  A lot of their home designs intentionally allowed air to pass through.

I want to be open to this idea ...  and at the same time it just sounds like you'll be cold! 

So ... at the moment, I rather like the idea of a design that gets air from outside.  And I wish to better understand the idea of something that is more open air.

And yet another little video clip.  This one shows the exhaust:  http://www.youtube.com/watch?v=wyeGvxfWkfY

BTW:  here's the stuff on cook stoves.

When someone refers to not wanting to live in a plastic bag, I have to agree.  But air coming into a house isn't necessarily in the manner of a draft.  Strawbale houses with concrete on the outside and lime plaster on the inside are said to be warm, even though a certain amount of air does work through.  I'm not sure of the principles, but they do NOT recommend wrapping the house with Tyvek-type products just for that reason.

Many late-model homes are said to be airtight.  Why would we want that?  It doesn't sound healthy, just off the top of my head.  Air needs to be exchanged, moisture needs to be vented, gas heat and wood stoves require air to burn, and we need air to breathe.

Even a house of passive solar design or that hot-water heating tubes in the floor (I don't know what it's called, exactly) don't use oxygen in the house, but I would still want some air circulation. Stale air just sounds bad.

Sue

Susan Monroe wrote:
Paul, where is the air intake? 

Do you think one of these would be suitable for warming a greenhouse at night?

Sue

Ernie and the permies at Mountain Homestead in Coquille did a rocket-powered greenhouse bed for starting plants in winter.  They got the soil up to about 80 degrees in February.   (They laid the duct pipes thru a box, and filled it with dirt, pretty thick so the top part wouldn't be too hot).

If you didn't want it that hot, you could make it separate from the garden bed and just fire it once in a while to maintain desired temperature.

Some plants might like the exhaust in with them, but it's not healthy for people to hang out in a space full of combustion by-products. 
I've wondered about creating a "doorless" greenhouse that would soak up the CO2 from a rocket stove exhaust, where you'd have to take down a wall or roof to get in and garden, thus ensuring adequate ventilation when people are within.

Regarding sealed houses:
Our solution to heat "energy savings" is to insulate the house and heat the air inside.  This is kinda like trying to keep a piece of toast hot, or using your blow-dryer to warm your hands.  Takes a lot of energy.  And any draft has a chilling effect.

Thermal mass operates on a different principle.  Examples you might have experienced:  Passive-solar floor slabs, masonry walls, adobe walls, masonry stoves, big flat hot sidewalks and cool basements in summer (most caves are about 55 degrees and that's  a lot of thermal mass) ... cuddling up with a hot cup of tea or baked potato, or bathing in hot water.

With thermal mass, only a small fraction of the heat is in the air itself.  The rest is stored in mass.  Like hot soup.  So a cool draft doesn't change the indoor temperature much.  If someone leaves the door open, the house will warm back up after it's shut without having to build a fire or turn the furnace on.  And you can arrange to have a cool head and warm feet. 

If you have an unlimited wall footprint, the best of both worlds is a well-insulated house which contains thermal mass.

This idea is discussed in more detail in Cob Cottage's book Hand Sculpted House.

Thermal mass heaters (masonry stoves, rocket stoves) are sometimes described as "democratic" because less-active people can cuddle up to them while hot-blooded people can sit at a distance.


Completely sealing a house, especially a house which is made of natural materials, often leads to moisture problems and rot/mildew.  This has happened on a lot of victorian houses in Portland.  Wood needs to breath. 
When there are no natural materials in the house walls, they're likely to be replaced with plastics that off-gas VOC's ("new car smell" or "new carpet smell," which makes a lot of people sick).  Internal air quality in either case is likely to be worse than outside air. 

There's a knack to getting the right amount of ventilation, and materials that work together. 

One option is to draw in outside air through a heat-exchanger.  This takes up space, and isn't terribly efficient (air is a good insulator, not a good heat conductor) but it would be one option for absolute energy efficiency without sacrificing health.

Like so much in life, it's a question of tradeoffs and choosing the right options for a given situation.

This has been a good discussion -- I have the rocket stove book, and am planning to build one in our garage for emergency heating (I live with my grandmother, in her all-electric house, and she doesn't want a wood stove in the house -- I want some way to keep from freezing if the power goes out, as happens once in a while!).  Our soil is heavy clay; I might have to add some sand to get a good cob mixture. 

Kathleen

Freeholder wrote:
This has been a good discussion -- I have the rocket stove book, and am planning to build one in our garage for emergency heating (I live with my grandmother, in her all-electric house, and she doesn't want a wood stove in the house -- I want some way to keep from freezing if the power goes out, as happens once in a while!).  Our soil is heavy clay; I might have to add some sand to get a good cob mixture. 

Kathleen

Probably; you want the mix to be more sand than clay, for a stable, non-cracking cob.

Rocket Stove Permitting:

Paul reminded me that folks here are curious about how our permit adventures are going.

We applied for a permit before building our rocket stove.  (Well, the landlady applied, and was given a woodstove/mechanical permit).  Then we built the stove, and a very pretty stove it is too:
Pictures at: http://picasaweb.google.com/eawisner

Then we called to have it inspected.
We have had 3 inspectors come to our house so far:
2 from the mechanical inspection department, 1 from DEQ.

They seem to all be agreed that our rocket stove is "cool" or "interesting," and have no objections to it on a personal level -- but it's outside their scope of expertise, and will need to go through some other approval process.

There are apparently exemptions for a wood-burning appliance (even a smoky ugly one) if it is antique, the only cooking device in a house, or the only source of heat.  But ours is none of these things.

We are waiting for a call back from the "OMOA," the alternative approvals process folks.

The way it apparently "should" have happened would be to get the design approved first. 

If you are planning to build one of these in an existing home, and prefer to ask permission rather than forgiveness, do not be fooled by clerks who think you need a woodstove installation permit.  Instead, try to find the person who handles design approvals for "masonry heaters," and talk to them about submitting a design for approval. 

You may also want to build a mock-up outdoors at the same location, so you can show the approvals folks what the heck you're talking about.

The main considerations that we've discovered here in Portland:
1) Foundations and earthquake safety: make sure your base is strong enough, maybe have an engineer run some load calculations for you to see if you can install it directly onto an existing slab.  Or talk to the approvals folks about what reinforcements are needed for a low, built-in, masonry "bench."

2) Fire safety and clearances to combustibles: Check local regs for things like air gaps, heat shields, distance from air intakes for other devices, and minimum thickness for masonry in a masonry heater.  If you meet or exceed standards for devices they do know about, it's easier to make the case for your process.

3) Chimney or stovepipe system:  We chose to buy a new stovepipe such as would be used with a woodstove; this is called a "factory-built chimney."  They were interested in the gauges of the pipe inside the bench, too.  Make sure you have suitable insulation and fireproofing around the pipe as it exits the wall or roof.  (You may be able to make a case for it being like a dryer vent, but we chickened out on this one.)

4) DEQ / EPA / UL approvals: Rocket mass heaters, like masonry heaters and fireplaces, are "Not a woodstove" and are thus exempt from UL sticker requirements.  The official code definition of "woodstove" excludes anything over 800kg (about 1760 lbs).  And they produce much cleaner exhaust than other masonry fireplace/heaters.
Our DEQ inspector only looks at outdoor smoke pollution.  He had nothing bad to say about our very clean white "smoke."

There's a more detailed report about our experiences so far, online at: http://www.journalscape.com/Ecca/2009-02-26-11:06

And there are other links to our work with rocket stoves, and upcoming workshops, at: http://www.ErnieAndErica.info

We're doing an Earthen Oven workshop in our backyard in a little less that two weeks (April 4-5), and there is still space available.  Please spread the word to Portland friends!

Thanks,
Erica Wisner
www.ErnieAndErica.info

And now I'm curious how this process is going ...

Is an "earthen oven" different from a "cob oven"?  Would this be a more indoor like appliance?

So I'm fishing through your links .... nothing new on the official front?

paul wheaton wrote:
And now I'm curious how this process is going ...

Is an "earthen oven" different from a "cob oven"?  Would this be a more indoor like appliance?

So I'm fishing through your links .... nothing new on the official front?

Nothing yet ... I've heard rumors that the relevant departments are reorganizing at a city-wide level, so I may need to make a few more calls before I get through.

"Earthen Oven" = "Cob Oven" in this case.  But as a category it could also include adobe, or other earthen masonry techniques.

You can build an earthen oven indoors with a chimney, but we want ours in the backyard for cookout parties.  It looks like we're going to wait for the drainage project this summer, though: the ground is saturated, like pudding, and the foundation is developing a slight tilt even without the oven on top.

-Erica

I was thinking that one could put an instant oven on a standard rocket mass heater.  Just make some sort of insulative cover/sleeve to go over the barrel. 

So you could put a pizza on a pizza stone on top of the barrel and then put insulated cover/sleeve thing over the barrel.  I would think that the temp under the insulation would quickly rise to over 500 degrees. 

Has anybody done anything like that?

Hey Sue, most of the time the air intake is where you build the fire - so it is from the room itself. One guy built in an air intake for the fire barrel by cobbing in a tube bringing in outside air. My impression is that these rocket stoves, when used with a thermal mass, are so efficient and effective, that taking in air from the room you're heating is not a problem.

I finally got around to putting together all of the rocket stove bits from the workshop into one video.  This shows 12 rocket heaters:  http://www.youtube.com/watch?v=LfKHVoCY2so

So this has video of 8 rocket mass heaters, 2 pocket rockets, the drawing I made for this forum and the image from the cover of Ianto's book.

Wow, it has only been a few weeks and the "12 rocket stove mass heaters" video has been watched more than a thousand times.  And the initial workshop video has been watched over 2000 times.

Neat!

I just tried to make a summary page called rocket stove mass heater.  Did I leave anything out?

Hi everyone,

This is my first post as a member of these forums.  I was so happy when i saw the terms and conditions at the registering page which just said:

          BE NICE

    I AGREE ( tick )

Its nice to have things simplified and actually relevant for once.

So.  Im really excited about these Rocket Stoves, Masonry Ovens etc..  Im from New Zealand and live in an area probably similar in climate (and earthquakes!) to northern California, Southern Oregon.  We have what i would consider poor house building techniques which are overly complicated, highly standardised wood-based construction with nationwide problems of dampness, very poor insulation - not in my particular area as it is warmer (north east coast) Where a gust of wind would cause the house to drop considerably in temperature.  And people trying to airtight their homes which in turn wastes alot of money on regulation, product marketing BS and causes dampness problems which starts the whole cycle again - see 'living in plastic bag' in above post.  But frankly after living in Germany with the amazing building techniques there i am disappointed in my countries housing.

In germany i came across a 400 year old (older than my country!) farm house with a masonry oven which kept a huge house warm with just a small fire inside a large tiled oven set in the centre of the house.  So now im researching that.

What i would love opinions on is this...
I am building a Yurt, about 4.5 meters wide (about 14 feet) and i would like to put in a Rocket stove, with some kind of thermal mass to warm it up in winter (no snowy winters here).  However the heat created by the initial burning and the metal drum may be too hot for the small yurt and be hazardous to the fabric walls.  So i was thinking of putting the fire and everything outside close to the yurt but far enough away as not to be a fire hazard (perhaps designing it as an outdoor cooking spot - pizza oven?) and the pipe and thermal mass inside the yurt as a bed base, or bench, or simply a brick/plaster structure with the chimney bends inside it like the butt-warmer, then eventually going up to a chimney.

What sort of things should i consider for this to work?
e.g. the distance from initial fire to thermal mass structure?
Heat loss due to complication in design (distance, length, pizza oven/bbq too big and not contained heat?)

Love the forum, the Cob houses, the enthusiasm and the info!

Phill
www.lafermemusicale.wordpress.com  - for yurt pics so far.

I think the whole thing needs to be inside.  If you have combustion concerns, put insulation between your combustion chamber and the wall.  Or .... just place it farther away from the wall.

  leah yu haven't read about rocket stoves, your drawings are crazy but funny. Pauls drawings are funnier.
    I have an related article i really like from google. Before you could just get it but now it seems you have to be an adobe  adobe reader or some other thing to get it i hope paul has brought theese comodities and can read it. or sue monroe isnot it her that does reseach or someone. Tap the words -russian stove rebuilt into the space given by google to say what your looking for and that will be enough . the rest of the title is  is, by carl oehme-stove mason and guy Amyot-aprentice Hamn heritage barnhouse
    It is about restoring an old masonary stove, a bit different but similar to the butt warming rocket stove, it says early masonary stoves in the canadien prairies were made by the mennonite inmigrants from russia, it is a russian peasant type stove sometimes referred to as grass burner. in one forum somone was asking about burning grass. They took it down and built it up again it is a really good article.
  Another good one, not so interesting because it is not so full of historical details or horse manure that aislates the wall from the chimney but good because it seemed to me the simplest way, most practical way to make a stove of this type, unless you are very rich and can have a really fancy one, you get it by tapping in the phrase -the masonary stove or russian fire place- . it is a grannies country store portal and you don't have to be signed up with any one special to get it. Looking for these two you will find lots of other articles. 
  The adobe wall insulate you from the heat of the stove you mentioned earlier, understanding about clay insulating comes from knowing about earth oven making . Look up earth oven workshop Maine.
    Oven clay is not the same as potters clay, For oven makers clay you want enough clay to hold the mix together and enough sand to make a ball of clay harder so that if you drop it from hip height a small ball of this mixture would hold its shape on hitting the floor. To little sand and it flattens and to much and it would fall apart. You mix hay into mixture. i found a you tube video of a man going out to find oven clay and showing  others about it but i can't remember how i found it.
      The first five inch layer of clay in an earth oven that will be the inside layer next to the flames does not have much hay in it,  this first layer is the the heat retaining layer the thermal layer, the next layer has more hay in it as it is an ainsolating layer and the last can have hay and manure in it. S the clay if the oven is fired gets really hot but also provides on the outside enough aislation to stop you burning. The really good site on this is -pockets of the future dot com- their siteis good  but boy is it slow, they are really nice but if you are busy they will drive you crazy.
  The sticks in a rocket stove burn in the first part and are fed in through the top and the air come in the top too  it is a down draft burning stove but in the upward moving tube round the bend the smoke burns making a tremendous flame. that why its insolated and so the air gets so hot it will run horizontal if their is no other way for it to go before going up the chimney, on the other hand they say that the clay can absorb so much heat that the smoke can't get up the chimney it cools down too much, so i suppose your bench should not be too long.
  iwas making some comment on stoves and today i remembered that the reason i found you lot was because you talked of stoves.
  As the smoke burns all up, it leaves little to pullute the atmosfere. As the masonary or clay take up the heat, heat gets stored and not wasted. So burn a bit of hay it will burn up fast but the masonary will keep the heat so it will last. 
 

rose,

have you seen my rocket stove mass heater web page?  Complete with lots of videos!

And!  There is a workshop coming up in a few weeks!  - probably a little far away for somebody living in europe.

Do you have links to the stuff you are talking about?

i did see the page i liked it i didnot see all the videos i think i must have mised them is it a two page one i feelocnfused. there sems to be more here than there was were i look before i pressed the reploy button i think i have seen them on you tube though, if they are of the fotos, i shall cheque it out again tomorrow. 
    my link i think i gave it badly is i don't know the address but i have tapped in the words from the paper i have on itto cheque out if you could get it with those words, i print stuff i like, and i found it, it worked but now you can only reach it if you have adobe reader or some like thing when i found it a year or so ago  don't think that was the case, the address for the first stove  i talked of or the words that work for me are  "russian stove rebuilt"    tapped into google , the full title has the following words after the ones i have just given "by carl Oehme-stove mason and Guy Amyot-aprentice  Hamn heritage barn.
the next address is              -the masonary stove or russian fire place-      google
  another address is              -earth oven workshop Maine-                          google
and the slow but good one  -pockets of the future, earth oven-                    youtube
                                              - russian stove rebuilt-                                      google.
I looked at lots of youtube rocket stoves and wood gas burners. lots of articles on masonary stoves. so may be these adresses don't cover everything.

fascinating stuff

makes you wonder why any standard fire place isn't fitted with an extra combustion area

anyone used this for cold smoking ham and fish or is the exhaust too clean?

cheers, Jan

You know, when I first heard about rocket stoves, and saw some pictures, I thought, "oh, I suppose it's okay for those 'fringe' people, trying to live off the grid and such."

Then I put my face into the exhaust of a rocket stove.

Wow.

You can't call it smoke, because it's not smoke; hardly smells of smoke even.

Later, folks made pizza in a cob oven. Ack! The black smoke POURS out of the front of those things!

Just think about how a neighborhood--or your garden/yard--can get rank, smoky-icky air from just one wood stove or fireplace burning nearby. A rocket stove doesn't do that at all.

After seeing how clean rocket stoves burn, I can hardly stomach the idea of burning wood the old ways.

And I keep thinking, why don't more people know about this? If it looks too funky with a recycled steel drum, manufacture a new, custom combustion chamber. Or, cob over it. Cob is beautiful, sculptural, comfortable, heat-retaining and summertime cooling art.

The cob benches are truly comfortable - surprisingly so, even without cushions. And they serve a purpose instead of simply taking up space like a masonry or Russian stove. (Admittedly limited understanding of the masonry kind of stoves, but I think they use thick masonry walls with chambers inside them...)

No matter how evangelical I get (so sorry to sound that way!  ) it's hard to understand unless you see it, smell it, touch it and feel it.

I want one for my condo. Some day...

j_cornelissen wrote:
fascinating stuff

makes you wonder why any standard fire place isn't fitted with an extra combustion area

anyone used this for cold smoking ham and fish or is the exhaust too clean?

cheers, Jan

I would think that it is too clean. 

But if you start a new thread asking about cold smokers, I have a design I made a long time ago that I could share ...

Jocelyn Campbell talks of masonry stoves and says she thinks they are a stoves with chambers in, I can give a fuller explanation. I should read all then pieces on this forum again before i write this, delete what i say if i repeat some one.
            The Rocket Stove Butt Warmer of this forum is a masonry stove, the clay is the thermal mass the horizontal path for the smoke or rather heat, is the equivalent of  the chambers of the masonry stove it stops the heat getting lost to the sky.
            Look up "tulikivi" if you want a really a really none fringe masonry stove. I love the curves in cob or adobe stove too, i think they're dead smart, you can get them from other bits of cob building too.
          As far as i can see rocket stoves of this forum  or are a sort of hobo's, a tramps, secondary combustion stove, rocket stove or wood gasifiers stove,  that fringe people have converted in to a sort of masonry stove, clay is as much masonry as anything else, does not the clay cook in the lighting of the stove so becoming brick.
            I found a bit on internet of a Siberian person living in the US who said of course they could make a masonry stove, they knew how to put in the right passages, with clay with some old bits of brick in it, and bobs your uncle it would work for thirteen years then you would knock it down and make it again. i don't know if i could find site again. it was a people asking questions site.
            The stoves talked of here and masonry stove work by the same principals, you get more heat for your wood because the smoke instead of spreading out too much and cooling down as it would in a open fire place is confined and in a warm place were it can expand enough to get enough oxygen but  does not expand enough to really cool down and so it ignites, so you burn all the burnables in the smoke, tar and such. You need a good supply of oxygen coming into your stove and there are stove designs that warm the incoming air. Fire is a chemical reaction between organic matter, warmth and oxygen.
          You can get the same effect in an open fire place if you build the fire in such a way you get a really big flame. I tried it two weekends ago and nearly burnt my house down i stood small twigs up instead of laying them down so there was a really good pull of air between them and used small bits of wood and as everything was really dry, it being summer, got more than i bargained for, i was experimenting with trying the Ávila way to make embers for a brazier. We just build open fires cold because we aren't looking for greater heat all at once but a slow fire that will warm us for longer and we don't want to burn our chimneys down. that such a fire wastes half the combustible energy in wood was maybe something we didnot realise.

        A hobos stove simply uses the extra heat to cook with less wood, if you burn the smoke you get a lot of heat with little wood. You have a long bit of tin can above where the wood burns for the smoke to burn in.
        The hobo's wood gasifier can stoves and by can i mean the ones you buy when you buy a can of beans or peaches, is designed so as to supply air to the part above the burning woodthey place a small can  inside a bigger oneand the air that comes in the holes in the bottom to feed the fire also moves up between the  space between the two cans and feeds into the tops of the upper part of the inner can helping the smoke to burn.
                In some of these tin can stoves the air comes in the top and then it is called "down draft" you put the kindling on top of your wood and light the can from above. A good trick of Lannyplans, to help light it is, a few drops of candle wax on top. The rocket stoves of this forum are "down draught" stoves.
 
              In old fashioned masonry stoves or one of these fringe rocket stoves you aren't just trying to cook a meal with a few sticks as hobos are, you want to heat your house all day. A fire that burns the smoke is a very hot and so fast, and as you want your heating to last, you put clay, brick or stone round the flame to catch the heat. These stoves are lit for an hour or two in the morning and that suffices to warm the masonry that keeps your house warm. These rocket stoves with clay benches are really masonry stoves they have the clay round them to catch and hold the heat.

              In "pockets of the future.com" earth oven" site for how to make an earth oven they got cracks in their oven as it dried. i thought I spent a lot of time doing pottery at school, that had they covered their drying clay oven with wet rags and plastic it would have dried slower, the out side would not have dried before the inside and the outside would not have cracked the clay of the people of this forum full of perlite is fired before it is dry it seems. In the pockets of the future videos on you tube they were using hay or straw instead of perlite when the straw burns it becomes air holes in the clay, very isolating, maybe in the outside layers of the ovens it does not burn and is hay isolation an d strengthening to your cob or earth instead of aripocket isolation. 
        In pizza ovens it is the first  firing that cooks the clay, you start with a small fire and build up the heat slowly in order to fire your oven.

    THE CORE PART IF YOU DON'T WANT TO READ TOO MUCH.
        In a masonry stove, so that the heat does not go straight up the chimney to heat the sky you make it snake through chambers.
    In the fringe peoples clay rocket stove stoves they make the heat go horizontally through a bench so that it does not go straight up a chimney to heat the sky.
      Masonry stoves can and do have benches round them but these benches are smaller and look uncomfortable.
        I suppose your rocket stove down draft affair could make the air snake up through  boxes, the whole containing these boxes is often positioned between two or three rooms to keep various areas warm.
      Masonry stoves  can heat an oven and a box full of water, cook and heat water for you.
      In a masonry stove you have a firbox where you burn your sticks and then an expansion chamber or secondary combustion chamber where your smoke burns and maybe it goes on burning in other chambers. You get a very big tongue of fire from a few sticks lit in a well oxygenated place.
    The masonry brick, stone, clay, the thermal mass takes up and stores the heat and keeps your house warm all day and one site talks of the owners leaving their house for two days and the house being still warm when they come back.
 
      Solar heating is even cleaner and does not use material that could help us to have good soils. may be with Fresnel lenses or really good reflectores directing the suns rays  towards iron plates we could get enough heat to heat up thermal mass and last all day, it would be dangerous but fire is dangerous the thing is to find ways of harnessing the heat. There was a sight with a design for this i shall look for it. agri rose macaskie.

Ok, so this design has a lot of promise for me.

For last winter I threw together an outdoor wood furnace, with a 1912 vintage parlor stove and some sheet metal siding. I insulated, built ductwork, etc and fired it up. The house stayed liveable, but just barely. We had pipes freeze on us once. I had to get out of bed every 4 hours to stoke the fire and in cases of extreme cold, every 2 hours.

The house we live in is a rental. The natural gas furnace is trash. We have an agreement with the landlord that basically we can do whatever we want so long as we take care of the place and pay rent. It's a 120 year old farmhouse that has went through at least two renovations, so the floorplan is a bit choppy.

So my question is this: How large of a space can this heat? Will I likely have to build several for such a choppy floorplan?

      I don't know, i suppose it depends how big the stove is and how efficient the burning is, its a free for all, you make it yourself and your a noble experimenter, at least you should not be getting up in the night.  You buy an expensive stove and there are probably guarantees, how big is your house how good are the walls, how cold the part of the worl how central can the stove be if its very cold these stoves get fires twice a day once in the morning for two to three hours and again in the evening. They don't heat up really well the first day of winter  maybe you need to heat them for more hours if you are starting from zero.
    One young man made one, whose site i mentioned in another letter and he said he only lights it in the weekend and it does not start to get cold untill late in the week, but he lives in the south of the country. probably Paul Wheaton can answer, he knows the people who use them.

  The thing about the clay rocketstove masonry stoves is that they aren't prohibitively expensive but maybe you need to be able to organise a group of people to help, or be a sucker for work and they are just as pretty as other ones. I don't know why they have to put all that metal in them.

  I have found some new sites for masonry stoves but of the tulikivi type, that is instead of having the burning, smoke flame, hot air, snake through a number of chambers one above the other from back to front and front to back again or go through a bench, the flame turning gradually into hot air rises to the top of the stove and passes down channels at each side of the centre part of the stove and then back up again or back through the fire box, its all a bit complicated.
  There is  a computer model of the smoke hot air flame flowing through these passages if you put the phrase "biofire kachelofen vespadorfen" into youtube.
      There is a video of a man making one out of brick in the wall of an old house nice because it look possible for anyone capable of building, he seems to use special bricks, if you put in the phrase "biofire kachelofen gordlist".
    If you put the words "warmstone fire place" into google you get a page that has the main lines or types of tulikivi  stove made by these people, with a picture of an example of each type and if you press on "custom tulikivi" you get the most amusing selection of designs. The more normal designs you can find easily in google.
    "biofire kachelofen vespadorfen"      youtube
    "biofire kachelofen gordlist"              youtube
    "warmstone fireplaces"                    google      Of choices of fotos on first page chose "custom tulikivi" for good samples of what their most amusing designs are designs. rose macaskie.

      I have thought of a new reason the  "rocket stove butt warmer" of this forum is better than other masonry stoves apart from affordability, it is built horizontally and so all the thermal mass that picks up and stores the heat is spread out across the floor instead of piled up in one place and so forcing you to strengthen the floor there.
      Another reason is they teach you to make it, your normal masonry stove maker is trying not to really let you see the important bits.
      The disadvantage is the open first part though i like one open fires but this one has no chimney above. It could be substituted for a fire box i suppose and some vents to let air in. rose macaskie.

This would be an interesting heater for a green house if the butt warmer part was used as a seed starting bed.

I've been tinkering with floor plans for a small house with a rocket stove (for a very cold climate -- Alaska), and one thought I had was to put the feed tube in the attached greenhouse, with the combustion chamber just inside the house.  Do you think that would work?  It would solve some of the house air issues, and also you would have sawdust and stuff getting brought into the house so much.

Kathleen

      Maybe you should put the end of the chimney in the green house. The carbon dioxide would be good for the plants and the plants good for the carbon dioxide, they would eat up the carbon leaving the di=two oxygens.
      When you first lit the stove each morning or evening, though, the green house would fill with smoke untill the heat really got up, i suppose. This suggestion is silly, if your stove was exhausting something poisonous then someone shuting themsleves into the closed green house full of exhaust, might have a turn or worse. rose macaskie.

It does sound as if the butt warmer would be a perfect seed bed heater.
  i did see the videos paul wheaton, and i liked them. i must look at them again too. I was interested in  the two stoves in which the fire  is on the outside of the house so that if a bit of smoke did happen to come out of the place where the sticks are fed in it woud only effect the air in the garden.
  I adore cob buildings, and furniture, if i were a richer woman i would have them or if i am energetic enough to make them. i have strarted experimenting wiht cob already.

I have an idea,
      Chimneys were introduced to stop the smoke polluting houses. In the third world the smoke just fills the room, i have been a long while ago in a room like that, all black from the smoke. Now we don't want to dirty our air anymore, couldn't we just have smoke rooms, just lead the smoke off into a special compartment for smoke.

Susan Monroe wrote:
Paul, where is the air intake? 

Do you think one of these would be suitable for warming a greenhouse at night?

Sue

Air intake is same as fuel intake - full fuel box tends to regulate the air nicely for a good mix.  Most folks have a lid, or spare bricks, to limit the air or shut it off in "Gotta-Go" emergencies.

Ernie built a rocket bench to warm a greenhouse bed directly.  (Dumped earth around the pipes instead of cob, deep enough to avoid burning roots.)  It worked great for early starting, except once they had an incident where someone closed a damper and some plants got killed by smoke. 

I want to do a smoke-tolerant "dinosaur garden" by the outlet of a stove one of these days.

-Erica Wisner
http://www.ErnieAndErica.info

Ernie and Erica, did you make up "the smoke tolerant dinosaur garden", or is it a real experiment. The phrase makes me wild with curiosity. God, no one here in Spain ever jokes around with me, i don't know if its racist, they don't joke with English sows, or just that they don't joke much anyway. I have known one that does.
,
  Plants really do vamp carbon in carbon dioxide gases, i heard that the trees in the Amazon have started growing quicker now there's so much carbon in the air and they really do eat enough to make a big difference, so really encouraging us to have more vegetation, as it does not just make a small difference it makes a big one.
        I get disheartened if i think i am walking up too steep a slope.  Thats one thing psychiatrist look for, i believe, if this person has stamina they get the thumbs up, if not, forget them, they have no emotional control.
    I would never do for the tour de France or other such bicycling events, i just stop trying if its too hard, though i am getting better at going on faced with all odds.
      I always thought emotional was being sad or happy, so i could not understand people whose main influences were psychiatry, they mean can you go on when something embarrasses you, embarrassment being for them an emotion,which it is in a way, it is being scared and scared makes youhave scared feeling . If your confidence is easily knocked then they say you are afraid too, i am afraid of lions, if my confidence gets knocked, i am just trying to have a sensible view of my own talents.  When they talk of whether people have fears they mean embarrassments or lacks of confidence, i wish they would polish up on their vocabulary so I did not have to spend years wondering what they were on about or feeling really confused about how to evaluate their criticisms because i did not have an idea what they had found wrong with me, they were talking double dutch as far as i was concerned.  agri rose macaskie.

paul wheaton wrote:
Yes!

I think the first step to warming a greenhouse would be the Oehler stuff.  But this would make an excellent second step. 

What 'Oehler stuff?'  Plastic?

I did consider venting the stove into the greenhouse, but as someone already mentioned, there could be considerable smoke at some parts of the burn cycle, so I'm not sure that would be a good idea.  Maybe a split vent, so when it's smoky you could vent outside, and when the smoke is pretty well gone, switch it to the greenhouse?

And I did think of the idea of using the pipe to heat growing beds -- especially in cold climates, that could really give you a head start on the growing season.

Kathleen

While it is true that during the day plants take in CO2 and give off oxygen, at night they take in oxygen. 

I strong suggest that you do not vent exhaust into a greenhouse.

I love rocket stoves.   Larry Winiarski is my hero.

Anyway, I had a question about yet another use for the vented smoke/steam that comes out from the rocket stove as exhaust.  Would it be possible to power a small wind turbine with the exhaust pressure from the rocket stove?  Is there enough output for even a small turbine and if so would that screw up the intake/exhaust relationship within the system?

Thanks for considering my lunatic fancy and I hope someone has some insight for me!

-Joe

shamanmonkey wrote:
Anyway, I had a question about yet another use for the vented smoke/steam that comes out from the rocket stove as exhaust.  Would it be possible to power a small wind turbine with the exhaust pressure from the rocket stove?  Is there enough output for even a small turbine and if so would that screw up the intake/exhaust relationship within the system?

I would have to speculate:  no.

When I look at the really big rocket mass heater used in myrtle ....  I went and looked at the exhaust and it was just a dribble slowly pouring out.  At that point the duct looked way too big fro the dribble of steam coming out.  Definitely not enough to drive any fan.

Interesting.  That being said though, what would happen if the exhaust duct was tapered progressivly smaller to increase the output pressure?  My fear is that it would create too much internal back pressure in the system, but I'm not sure exactly how the whole thing works in that regard.  Has anyone tried that or is there an obvious reason it woludn't be a good idea?

I think that is exactly what was done with myrtle.  It starts at eight inch and about halfway through it shrinks to seven inch.  By looking at the exhaust, I would guess the hole at the exhaust could have been two inches and it would have been about the same.  BUT!  That's after the fire has been running a while.  I suspect that when the fire starts, the bigger pipe at the other end make an important difference.