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rocket mass heater myths - youtube video series  RSS feed

 
master steward
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"they cannot be that efficient"




"carbon monoxide poisoning - everybody is going to die!"




"heating with a big hole in the wall; the ziplock back effect; tipi results"



 
paul wheaton
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More episodes coming up in this series includes:

- you have to use small wood

- the hot barrel is too dangerous

- you need more wood than just twigs

- they are too ugly

- you cannot violate the laws of physics or thermodynamics

- they are for tinkerers only


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Paul,

I'm really enjoying this series. Thanks for posting the videos.

An anecdotal example of the importance of thermal mass: In mid-October I was camping on our land in southern Utah during the first hard freeze of the season. The next day I was talking to a guy in town, complaining that I could no longer sleep under the stars because of the cold, and he suggested an old hunter's trick he uses. He puts a bunch of rocks in his campfire and then just before he goes to bed, he digs them out, buries them in the sand, and puts his sleeping bag on top. He claims he can sleep comfortably all night no matter the temperature.
 
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"- they are too ugly "

Hey lets put that one to bed quickly --



Swedish tile heaters operate in a similar manner to a RMH and they are very stylish. No reason a RMH can't be suave.
 
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The conversation about mass-heat being perceived as warm all over even within a cool room strikes a chord with me. I'm a big fan of slippers; warm feet = warm body! So it makes sense to me that simply adding a heated bag of cherry pits to the foot of the bed or a heated brick to the feet in a wagon or sleigh, as our grandparents did, would make a cold room or ride comfortable; a warm floor to walk on can keep a person feeling warm all over, too (and last longer... and burn less fuel...and avoid sudden temperature fluctuations...).
 
Grant Holle
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With respect to radiant vs convection heat, Tesla's owner manual recommends using the seat heater instead of the cabin heating to extend range. It's common sense, but still nice to know that Elon Musk is on your side.

[Edit: oops, I think I meant conduction vs. convection.]
 
Cd Greier
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My ground-level bathroom abuts the masonry heater so we modified the "bench" to act as the floor of the shower. So far so good!
 
paul wheaton
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Next in the series.  This time the myth is that a rocket mass heater is pickier about the kind of fuel it can use

 
paul wheaton
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A new addition to the rocket mass heater myths series.  This time about how a rocket mass heater is dangerous because it is too hot.

 
john mcginnis
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paul wheaton wrote:A new addition to the rocket mass heater myths series.  This time about how a rocket mass heater is dangerous because it is too hot.


There is an ace in the hole -- regulation. I suspect it won't belong before wood heat/cooking is regulated away. Now the way that is structured in the US is that it is targeted against the makers of wood heated appliances, not the consumer. (govt views us as a lump of fat with cash and no brains...) The ability to build your own heater may be only way one will be able to have wood heated structures.
 
paul wheaton
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Another.   This time there is doubt over "heating your home with the twigs and branches that naturally fall off the trees in your yard."

 
paul wheaton
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Seeing "Myths Dispelled" keeps making me think of Magica De Spell.

And so, I couldn't resist making this .
Magica-Myths-De-Spell.png
[Thumbnail for Magica-Myths-De-Spell.png]
 
Nicole Alderman
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She needed fire...

(Thing #4,975 That I Do Instead of Sleeping: "Make Magica De Spell Dispense Fire into a rocket mass heater for No Reason")
Magica-Dispells-Fire-Myths.png
[Thumbnail for Magica-Dispells-Fire-Myths.png]
 
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HI, On the thread of 'the barrel is too dangerously hot'  I've got I think, a simple question.  How hot should the barrel top be getting?  Depends?  OK, its a six inch system, with a masonry manifold, and I'm burning mostly pine and fir.  Its been up and running since late October, intermittently, because I dont live there.  There is still some moisture around the edges of the mass, but the burn chamber should be dry by now, no?  I've gotten it up to 520˚ F just over the top of the heat riser, after a brief burn of 1" minus sticks.  whaddya think?
Dave
 
paul wheaton
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industry convention is not thermodynamic. electric heat is 100% efficient, but heat pumps are not 130 % or maybe 90 or so . not sure where you are getting this info.  after you get the heat how you store it and use it is of course another efficiency, problem but not the same problem as the electric heater .   Also if you have to talk about what the comfort set point is, if you agree its 50 degree F or 45 F or 60 F this changes the calculation completely/  Because you are changing the outside temp differential. relative to your calculations.   So in order to do a real test of the stove , you have to use it  in an exact same situation compared to another heat source all at the same time in the same conditions. otherwise you can't  compare them accurately.
 
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The reason it takes less wood to heat with a rocket mass heater is simple, and you circled it several times in your video.  The reason is that the RMH is very efficient, and a lot more EFFECTIVE.

The RMH is very EFFICIENT, because it burns 100% of the fuel.  Efficiency is a measure of how much of the chemical energy in the fuel is converted to heat.  Effectiveness is a measure of how well that heat accomplishes its intended purpose (most likely keeping the people in the building comfortable).  So if you can be just as comfortable with 1/10 the amount of wood, the correct terminology would be to say that the RMH is 10 times more EFFECTIVE at maintaining a comfortable environment than the wood stove.

I have a RMH in my uninsulated shop in Northern Canada.  It is uninsulated because I don't heat it often enough for insulation to be needed AND the RMH generates radiant heat, and it stores heat in the mass.  When I am four feet from the heater I will be quite warm, but I can still see my breath.  The radiant heat is not heating the air, it is heating me directly.  Radiant heat only heats mass that it cannot go through, e.g., people, floors, walls, etc. so heat is not wasted heating stuff that does not need to be heated.

Another factor is that the mass absorbs almost all of the heat not converted directly to radiant heat at the barrel, and slowly radiates it back into the work area.  Hydronic radiant floor heat works in a similar way.  At the exhaust pipe, there is almost no heat left in the exhaust stream because all of the heat is being converted to radiant heat or it is stored in the mass and radiated back slowly. 

In any radiant heating situation, you can typically drop the air temp significantly and still be comfortable.

As you discussed, if you are sitting on, or working near the mass or the barrel, the heat is used much more effectively than if you were to have to heat the mass of air and blow it around.  Also as you discussed, if you open the door, you are not trying to heat all of northern Canada as you would be with a forced air unit.

An electric baseboard heater can theoretically be 100% efficient as all of the electrical energy that it uses is converted to heat (ignoring the minute inductive and capacitive losses in an an AC system), but it is not at all effective because most of the heat is wasted heating the air to create convective currents.  As you mentioned, heated air can escape.....ergo, not effective.  As you also mentioned, that hot air rises and sits near the ceiling, so unless you are a bat hanging from the rafters......again not effective.

A heat pump is not really 130% efficient, it just moves heat from one place to another, so while you do get more heat energy inside than you put into the system to move the heat, you are lowering the temperature outside, so thermodynamically, it is not more than 100% efficient.  It is, however, more effectively using the energy input because the great outdoors is a huge heat sink compared to the indoor area being heated so we don't notice a change in outside temperature.....we are only concerned with the inside temperature.  No system can be more than 100% thermodynamically efficient.  If they could, we could build a perpetual motion machine and put all those oil companies out of business for good .

Darryl C.
P. Eng



 
Darryl Cornish
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In response to Kevin, the set point for comparison, has to be the comfort level of the occupants.  If you have radian floor heat and you set the air temp at 70 F, most occupants will FEEL much warmer than in a building with forced air set to 70 F, because the radiant heat is heating their mass directly, and the conductive heat from the floor to their feet will keep their feet warm and warm the blood in the feet which then warms their core.  Typically, for the same comfort level, radiant floor heat will have the air temp at chest height about 10 F cooler than forced air.

Darryl C.
P. Eng.
 
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I have so many times in my life experienced sitting in a living room with one of those little fat bellied ovens - and it was so warm that.people ended up sitting in t-shirts even with a snow-storm outside. Next morning the oven is out and the house is freezing cold. In those Sweedish houses with the old masonry heaters, the heater would still be warm in the morning, but you would have to litteraly hug it to feel the heat. The new modern ovens that I have seen in Denmark does burn the exhaust AFAIK, but only on max heat - which has the same problem as the old fat bellied ovens - the room almost gets too warm to be in. And they still let most of the heat out through the chimney... The ovens I have seen here in Spain are almost all a complete waste of wood... mostly there for the ambience. Guess people in the Nordic countries have had to make more efficient ovens, otherwise they could spend all summer collecting wood and not have time to grow food... (I have actually met some homesteaders where the husband spent all summer collecting wood and the wife would grow food... very inefficient).

I have never experienced a RMH, but intuitively it maLes sense. I am an engineer too - and I don't understand how and engineer can fail to understand that industry standards are not the same as the laws of physics....

Wrt. how they look - I personally prefer a sort of a conservative minimalist look in my house, and most RMHs that I have seen are much too hippue for my taste. But there are pkenty of conservative looking RMH pictures out there - this one esp. Comes to mind, not much hippue feel about this one: http://www.flickriver.com/photos/onyone/4149423745/
 
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I really enjoy this video series, but my mind keeps asking, "to what end?"

I'm unfamiliar with the source text from this unnamed woman, is it very popular or widely read?

Is the point to give a rebuttal to the woman or to people who share her perspective?

My impression is that she has offered a professional opinion on a subject that she has only considered theoretically, and wonder if she has ever spent any time with an actual RMH in operation, or if she has a vested interest in discouraging people from exploring RMH technology.

In either case, I can't speak for her, but I would find it difficult to call myself a professional, an expert, or any sort of leading authority on a subject, based on my own ignorance of the subject matter or being financially incentivized to deceive and mislead people.

I would be very interested if there were efforts made to persuade this woman, not just through debate or sending her this video series, but by challenging her to spend a winter with one, perhaps something akin to the $10,000 bet between Paul Ehrlich and Julian Simon, or the similar $10,000 bet between Matthew Simmons and John Tierney.
 
paul wheaton
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Is the point to give a rebuttal to the woman or to people who share her perspective?


In january of 2009 I saw my first rocket mass heater in operation at cobville.  I saw the fire burn sideways.  I felt the luxuriant heat of the cob mass.  I saw the tiny spec of wood being used to produce so much heat - while just two days ago I was stoking a conventional wood stove with heaps of wood trying to stay warm.  I sat in front of five experts in rocket mass heaters and asked "why don't more people know about this?"   Nobody knew. 

Why is it that rocket mass heaters are not in half the homes in the US now?   A weekend and a few hundred dollars in materials could save thousands, or even tens of thousands of dollars. 

One of the reasons could be the bizarre negativity from people that have never run one. 

This particular woman expressed her position in a written format on the internet that is easy to work from.   It is pretty typical of the sort of yucky stuff we see.  But it was made even better because of her claims of being an engineer who consults on building energy efficiency.  Made better again by her obvious dumbfuckery.   And made even better still because she was just so very mean and nasty.  To top it all off, I have actually met this woman, in person - and she was ridiculously mean, nasty, stupid and vain in person too.   I think she is a perfect example of sort of ick that makes it so that rocket mass heaters have not made it into a hundreds times more brains and homes than it has.   I am not certain, but I think that at the time she was working for a company that sent me an email begging for donations: "some people in montana will have to choose between food and heat.  Send us money so we can buy them wasteful amounts of heat."   I replied to those emails with links to these articles:

https://richsoil.com/electric-heat.jsp
https://richsoil.com/rocket-stove-mass-heater.jsp
https://richsoil.com/wofati.jsp

But they never replied.


These videos are designed to address common dumfuckery around rocket mass heaters.  If somebody on the internet utters a bit of dumbfuckery that smells like one of the engineers stupid comments, then I hope that a person will post a link to the proper video.

We also need videos that represent helping a person go from never hearing of it before, to hearing about it for the very first time.  Like this:



But I think I will need to make some more at that level, introducing rocket mass heaters to different groups.





 
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paul wheaton wrote:
Is the point to give a rebuttal to the woman or to people who share her perspective?


In january of 2009 I saw my first rocket mass heater in operation at cobville.  I saw the fire burn sideways.  I felt the luxuriant heat of the cob mass.  I saw the tiny spec of wood being used to produce so much heat - while just two days ago I was stoking a conventional wood stove with heaps of wood trying to stay warm.  I sat in front of five experts in rocket mass heaters and asked "why don't more people know about this?"   Nobody knew. 



I have known more than a few engineers for which I was surprised that they managed to graduate.  It's like the old joke, modified...

"What do you call an engineering student that graduates at the bottom of his class?  An engineer"


The reality is that the vast majority of engineers today are technical bureaucrats, without an innovative bone in their bodies.  The sad truth is that the quality that people like you, Paul, possess is fairly rare among humanity.  It's very much related to the Curse of high intelligence (that's a book, BTW) that allows a small minority of people to rapidly 'test' variations in their mind before putting the best results to a physical test.  If it were not for the very few people that truly posses the ability to 'innovate' (not just create pretty artwork, not the same) humanity would still be living in mud huts.  And not the wofati kind.  The common culture is predisposed to reject such innovations and their outcomes as fraudulent, if the common mind has trouble with understanding the innovation itself.  Bill Gates thought the Internet was a fad, and I've been explaining how Bitcoin works for seven years.
 
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On the topic of 'violating the laws of physics', I have a few comments I'd like to make. The "75% efficiency" comes from three testing assumptions that don't apply to RMH.

1) In a conventional wood stove, they don't draw-in sufficient Oxygen to complete the combustion of the hydrocarbon gasses. There is more energy coming from the wood-fuel than the stove is buring, but the conventional stove doesn't / cab't take advantage of it.
2) The exit temperature of a conventional wood stove needs to be held at above 425oF to prevent the formation of creosote. The creosote is the condensation of these unburnt hydrocarbons (the unburnt fuel).

A RMH *does* draw-in sufficient Oxygen to completely combust all the freed hydrocarbons, so RMHs get more heating-value from the same lb. of wood than a conventional stove. ALSO, because RMHs don't need to avoid the creosote problem, they typically design the mass to capture more of the exhaust heat - they add mass and lower the exhaust temperature to about 200oF. The additional capturing of heat means they *again* get more heat from a lb. of wood than a conventional wood stove. The extra Oxygen allows RMHs a double-whammy of efficiency.

Finally,
3) Conventional wood stoves primarily heat the air in the room.

A RMH stores the heat in a mass, which means its primary heating mode is radiated (light like a heat-lamp). Yes, a briefly opened door will loose a lot of hot air out the door, while the same briefly opened door won't loose any significant heat from a thermal mass (bench, etc.). There isn't a 'speed' of BTUs "whizzing past" the home owner and flying through the walls. While amusing, that description is a mischaracterization of how heat flows.

Given the above, conventional wood stoves are being uniformly and systematically tested, so they can be compared to each other. That's really handy. When trying to compare against a RMH, we have to understand that the rules of the test need to change. Under the adjusted-rules, a conventional wood stove will likely come-out as 15% to 25% efficient, and a RMH's results something like 90% efficient, which makes Paul's and other's claim (and personal experiences) of 80% to 90% reduction in wood-consumption quite believable.


-Scott
 
paul wheaton
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In one of the videos, Erica made a really excellent point.  Something I had not heard of before that I find myself repeating.   And it makes me think that we need a bit more something for the batch box rocket mass heater.

Erica pointed out how a conventional wood stove will need to have the draft open during the burn.  And now it is typically a straight shot from the draft, up the chimney to the outdoors.   So when the fire is out, all your heated air keeps going on up the chimney.  So, your conventional wood stove operates at negative efficiency. 

So then a person can say:  chalk that one up to an external air intake.   But that is just as bad in a different way.   If the air temperature outside is cold, then colder-than-room-temperature air is brought into the stove and the stove then cools the room to cooler than room temp.

If we look at a j-tube rocket mass heater, there two HUGE advantages in this space. 

HUGE ADVANTAGE 1:   The barrel acts as a thermal P-trap.   When the fire slows down, the heat accumulates in the top of the barrel and the air stops moving.   It doesn't go outside.  Eventually, the barrel will cool enough and air will move again.   But usually ....

HUGE ADVANTAGE 2:  at the end of the burn, the bricks were moved over the wood feed.   So this does a pretty good job of stopping the air flow.

NEW ADVANTAGE 3:  At the jamboree this year there was a lot of effort toward stratification chambers.  This would work as an additional P-Trap in the system.




 
paul wheaton
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Creighton Samuiels wrote:  It's very much related to the Curse of high intelligence (that's a book, BTW)


Our house is in mourning now as a person of high intelligence that we know of did the suicide thing.  High intellect is often tied to madness.   In the words of The Tick: "You're not going crazy.   You're going sane in a crazy world!"  Perhaps the more intellect one has, the more they can understand.  And the more one can understand, the darker the world is. 

So the mission is to make the world a better place.   rocket mass heaters are better than electric heat, natural gas heat, propane heat and conventional wood heat.  Thousand of people have used them and results are repeatable.  Switching to a rocket mass heater could save a family thousands of dollars.  Maybe even thousands of dollars per year.  It seems like that would be motivation enough. 

Sometimes I think it will be a slower road.   Just the people that get it get to have it:



So the people that understand get to have thousands of dollars more.  Eventually, others will think "I want thousands of dollars too!"

 
Creighton Samuiels
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paul wheaton wrote:
Creighton Samuiels wrote:  It's very much related to the Curse of high intelligence (that's a book, BTW)


So the people that understand get to have thousands of dollars more.  Eventually, others will think "I want thousands of dollars too!"



Perhaps, but probably not without some kind of advertising campaign or significant public service campaign, and I don't consider either very likely.  I compare the idea of a do-it-yourself masonry heater to the concept of a samovar (https://en.wikipedia.org/wiki/Samovar) which is a tiny water heater intended to heat water to just below boiling, and keep it there.  Utilitarian ones were traditionally heated with tiny wood fires, very similar in nature to an L-rocket (but the fire column wasn't insulated, but water jacketed) or a Kelly Kettle.  They were very common in the cold regions of the former USSR, and were used to make hot drinks to warm the humans directly, from the inside; as well as provide ready hot water for hot water bottles, etc.  This is an ancient technology, that can be traced back for hundreds of years, that has kept the Russians (& the Turks) acceptably warm during their harsh winters.  And yet, these are almost unknown in the "West".  I actually have a modern electric one sitting on my counter about 15 feet from where I'm sitting, and I use it daily all year long, but more often during cold periods.  I use it even during the summertime to brew tea before chilling it.  Since the samovar keeps the water added to it above the pasteurization point for hours at a time, the water is also sterilized; so the source can be filtered water from any natural (uncontaminated) body of freshwater without any significant health risks.

So the West uses expensive antibiotic filters made from silver, (http://www.bigberkeywaterfilters.com/) while the Russians just heated it up to boiling with a few pinecones.  The main reason that the West still doesn't really know about the samovar, and it's many advantages, has most to do with the fact that a countertop water heater can't really be patented, nor does it contain any parts that require modern machining or manufacturing.  They are basically just tiny water heaters, some of which look really ornate, while others just look like a steel bucket with a tap.   If I ever do build my own RMH, mine will have a samovar built in.
 
paul wheaton
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The last episode of season 1:  for tinkerers, garages and shops only!



What are some topics to cover for season 2?
 
Creighton Samuiels
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paul wheaton wrote:

What are some topics to cover for season 2?


Something about this particular episode made me think, is there any reason that the feed tube of the J-rocket can't be made with glass block?  I know that the feed tube doesn't get as hot as a standard wood stove door, so maybe a quartz panel is not necessary.  Even if a glass block can't take it, what about a Pyrex (borosilicate) panel?  Either option, if workable, would allow a firebug to see something firelike from a sitting position a few feet in front (or beside?) the feed tube.  And if that wouldn't work, or if the actual burn section of the feed tube is too low/deep into the structure to see well; what about a pair of stainless steel plates, polished to a mirror finish, that form a periscope image?  This periscope could also form part of the secondary air supply, pulling fresh air past the lower mirror all the time so it won't have to be cleaned daily.
 
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Maybe a different series could be "rocket mass heater designs"?

Click on the the thumbs up for this post if you would like to see a series like "myths" but it covers design points such as:

- glass in the wood feed
- pebble style vs. cob
- metal in the core
- materials for the riser
- use of cements for the core

??
 
Creighton Samuiels
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paul wheaton wrote:Maybe a different series could be "rocket mass heater designs"?

Click on the the thumbs up for this post if you would like to see a series like "myths" but it covers design points such as:

- glass in the wood feed
- pebble style vs. cob
- metal in the core
- materials for the riser
- use of cements for the core

??


Actually, I'd like all this data.
 
Creighton Samuiels
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Creighton Samuiels wrote:
paul wheaton wrote:

What are some topics to cover for season 2?


Something about this particular episode made me think, is there any reason that the feed tube of the J-rocket can't be made with glass block?  I know that the feed tube doesn't get as hot as a standard wood stove door, so maybe a quartz panel is not necessary.


I've found that commercial glass block manufacturers do make fire 'rated' glass block, with up to 90 minute ratings.  This does not mean that they are intended to be used in an actual fire containment structure, but that they are tested to prevent a fire from spreading from one side of the block to the other for this amount of time.  This implies that they are pretty well insulative and that they are designed for some amount of direct fire exposure, so this would be the best place to start.  I guess the next step would be to buy some of this glass block, and see if I can destroy them in a J-rocket.
 
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Season 2 topic suggestion: batch rocket mass heater - build it right the first time then tinker (ask Ernie & Erica to share content from their builders book)
 
Grant Holle
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I'd love to see a compare and contrast of the different styles of rocket mass heaters: j-feed vs. batch box; barrel vs. bell (stratification chamber); riser vs. riserless...
 
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paul wheaton wrote: What are some topics to cover for season 2?


I would like to see a rocket mass heater for a tiny home, truly tiny, like 100 Sq ft, that doesn't come with the caveat: you can open the windows when it gets too hot. It seems that to get a truly clean burn you have to get things hot and that means a certain amount of coals and that means more wood than otherwise needed for a tiny place in a moderate climate .(SW Washington).. ?? Any and all thoughts gratefully received.
 
pollinator
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I would love to see a video of cleaning RMH ducts after let's say a year of usage. Especially the ones that are incorporated into a cob/rock bench. How to do it properly, how often, etc.
I know that this is being mentioned in your "Care and Feeding of a rocket mass heater - Five experts share their techniques" video, but I would like to see it in more details.
 
Mother Tree
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Barbara Kochan wrote:I would like to see a rocket mass heater for a tiny home, truly tiny, like 100 Sq ft,


try this thread - looks like the video already exists tiny house rocket mass heater: the cyclone batch style
 
It will give me the powers of the gods. Not bad for a tiny ad:
Shippable core kits will be available January 1, 2018!
https://permies.com/t/72909/Shippable-core-kits-January
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