running a Rocket mass heater

I have been reading and watching but not getting a lot of information on running these heaters. I have the book ordered and am contemplating investing in videos, but a few things I've read brought up some questions on the use of this heater in our climate, house, etc.

Right now we heat our 1500 square foot one level modular home (28x56) with a conventional wood stove. We live in a decently cold climate and get 2 months of minimum -30F, often snow from 1st of October til April and bitter cold. In order to keep the house liveable (we don't mind it being 60-64F) we use 5-8 cords per year and shut down the one side of the house, choosing not to use 2 of our 3 bedrooms, so we are only heating about 1000 square feet. Our Pacific Energy stove works well for us - I stoke it morning and night, but if it hits -50F I get up in the night so it isn't so cold by morning. It banks easily and I never have to restart the fire as there are always coals 12 hours later (I hate starting fires).

We are moving to a different place, but it is still a one level double wide mobile home but with more land. The house is larger and I have some concerns about heating a place this big - 2400 square feet! We can again close off 3 of the 4 bedrooms but it still leaves a larger home than we heat now. It is an open floor plan with kitchen, family room, dining room, living room all one big square, 3 bedrooms off the living room and then other side of house is last bedroom and bathroom. Stove would be in the family room as that is central to the other rooms, but I know this expensive wood stove will NOT heat a house like this and I just cringe at running 2 stoves and having to do as much as 16 cords of wood every year (we live in farming land and very little close "wood")

I happened upon Rocket stove heaters a couple of days ago and they sound wonderful! But nobody has mentioned how they run this stove - they talk about needing to tend it for 1.5-6 hours and then let it die out and heat the house via the mass. This means you guys are starting the fire every single day? When you talk about tending the fire, are you having to add multiple small pieces every 1/2 hour or something - what do you do to "tend the fire"?
Many have said you can't burn cordwood - my husband cuts our wood and doesn't cut it small. Would it all have to be these tiny 1x2 inch piecs?

Is the RMH a good option for a home this size that is not on multiple levels or am I dreaming to think we could heat something this size with RMH? I have read that the book addresses shoring up wooden floors so I will read up on that when the book comes.

We homeschool and have a lot of other things going on that require us to stay home (we milk a couple cows, have chickens, pigs, garden, etc) so tending something for a bit time is not a problem, I just want to know what the tending involves. I don't like building daily fires, but I also don't like putting up 20 cords of wood, running multiple stoves at the same time etc and would rather tend a fire.

I have read not to use a RMH on a house this size as a main source of heat. What would the recommendation be then?

I am not concerned about the build itself, just want to be sure this is the right heater for our house.
Thanks for any experience, critiques etc.

Jay Stegman : You should be able to make a phone call and get at least last years heat energy usages, tho the answer may be in Watts, Gal.s, Cu. Ft., Therms, or Btus,
- they may try and just give you a dollar figure over the phone or require that the request comes from the Bill paying person of record ! Start there !

The response that I made to Erin Hatfield in the Rocket Stove Forum/Thread - 'Building a R.M.H.on a wood framed floor' - could have been written for you, For every 3
cuts your husband is in the habit of making he will have to make 5, and then most of the wood will have to be split down to 2X2 for the First 2 hrs of operation, that means
that the person who made the 1st fire in the morning must be in residence and tending the fire or handing that job off to a 2nd person! After 2-ish hrs an 8 system'' will
take all of the wood in 3 - 4 pieces that can be stuffed into a 7'' X 7'' system.

Because of the freakishly high temps a well constructed Rocket Mass Heater R.M.H. runs at, and the fact that the Thermal Mass Bench 1st stores heat energy, and then acts
as the heating source all night long- without further wood fuel being burned for as long as the next 20 hours- or longer- it creates the conditions that reduces the amount of
wood fuel used to as little as 1/3rd the prior amount. 1/2 the previous amount of wood is easily obtained with careful operation, This is true because the best that your old
wood stove can do is so very poor!

Having said that , I can not promise that a single 8'' R.M.H. can handle your heating load, certainly a combination of two 6'' systems can handle your heating load but even
with the reduced wood fuel requirement. I do think that many people would just as soon 'turn up the thermostat' on What ever came with your Double wide as a heating
source !

I am reaching here- but, if a family member is spending several hours a day in town this is a better source of wood fuel- mostly pre-cut to the most usable material sizes for
your units fuel load. Usually there are often cords of Free fire wood parked behind mall stores because they will have to pay to have it hauled away !

Using a R.M.H. requires a lot of re-thinking old ways of doing things, It is always worth the effort ! For the Good of The Craft !

Your questions and comments are solicited and welcome, think like fire, flow like gas, Don't be the Marsh mallow ! PYRO - Magically Big AL !

We are not really on speaking terms with the previous owners, as some issues came up between all of us that they have bad feelings over - a different story that involves them accidentally spraying our 20 acres pasture with Atrazine AFTEr we bought it . . . I know they were rarely home (very involved in sports for their children and said they came home midnight almost daily after their long work days). And I know that most people keep their houses much warmer than we do

I saw the video Ernie and Erica made of their newer RMH and the pieces they were showing as junk wood were the size we have used so I was surprised by everybody telling me you have to have the small 2x2 inch pieces for the whole burn. So thanks for clarifying that.

The wood stove does a good job when it is at 32 here. . . most of our winter is no where near 32, so we just exist in cooler temps, dress well and do a lot in the living room/kitchen . I was hoping that a RMH would be able to do better than that because of the mass being used to store heat - maybe the house won't drop to 52 each night and that would be good enough for me!

I don't THINK a single 8' RMH would do worse than our wood stove, but for the cost to put it in we are not out much if it does. I'm just trying to heat a bit more space with hopefully less wood and not a lot of investment (not asking for much, eh*G*). The year we ran out of wood, we paid $400 a month during Jan-April to keep our house at 55F during the day and 42 at night. . . the wood stove means we can actually be comfortable for 1/4rd the cost if we have to buy wood. Most of our neighbors spend $800-1200 per month to heat without wood. We keep our thermostat to 44 and never use it otherwise - I can't imagine not burning wood!
We are 90 miles from any store or mall that would have wood - but I know what you mean about sourcing it. When we go to the larger center for supplies they often have monstrous piles of small wood they are getting ready to burn in their incinerators (menards, lowes etc)

A question - do the "portable" ones (look to be about 8 feet long) do a good job compared to permanent? The only reason I ask is that we most likely will not stay in this new location for more than a year before looking for a place with trees on it. We are thinking a RMH might have to come out in a year so should we be thinking portable?

Jay Stegman : Ask your neighbors they will know who was delivering what where, to include asking the neighbors to hold a check for a common delivery driver !
Since the oil embargo of 1970, the dealer of record is required to share this information, most dealers have been supplying this information so long they don't
have any corporate memory of doing it any other way, this is why you might have a minor problem with a company that has forgotten it's a Federal law. Dig for
it, it's your right by Federal regulation ! ( you didn't vote for it it just happened )

Actually most thermostats shut off if you turn them down below 50*F, so if you already have 1 that goes lower, consider replacing it and taking it with you - On
2nd thought my thermostat is Over 60 yrs old, I don't really know what is common anymore !

Yes not the whole burn just to start, start being as much as 2 hrs, if the wood is not perfectly dry, or the home owner forgets to feed her dragon !

I am not the person to ask about the so-called portable Thermal Mass Bench, Paul Wheaton is still trying to improve it, Ernie and Erica Wisner having tried it,leave
it to P.W. to do so.

If you had an unlimited supply of bricks and/ or paving stones, you could consider the whole thing a multi-level paving job, the sand could be loosely packed
around the bricks, because no one is going to walk on it, taking it back apart should be easy, in any case every elbow that you use reduces the amount of
horizontal piping you can use,and you will need more horizontal piping to store and distribute the same amount of heat ! You will have to discover where you can
create the longest straight heat runs, and weigh it all against the 'creation of Vertical chimney$ !!!' I do hope this helps ! For the good of the Craft !

As always, your comments and questions are solicited and Welcome, Think like fire, flow like gas, Don't be the Marshmallow! PYRO - Magically BIG AL !

Hi Jay.

I've had to check what is a double wide. Not such a thing where i live. Well, first question is, how strong is the floor?

About tending the fire, and lighting it. First starting it, when it's cold, is simple as pish in a J tube. Make little sticks, finger size, 6 to eight inch bundle should be all right to start your rocket. Chruck enough in the feed to fill it, that would be about 1/2 wood 1/2 air space, may be a bit less wood. Pour some ethanol of some kind on top of this, it seeps down the wood. Throw a match at it. Tho, never ever do this on a hot stove. The flames will go up the wrong way for the first few seconds, and then, usualy the fire reverts, and goes horizontaly in the burn tunel. Sometimes you will have to prime it at the bottom of the vertical chimney stack, where you should have a T with a plug for cleaning, and priming the draft. I do it the same, light a bit of ethanol.


So, after this being said. If you want to use bigger wood. I would advise a batch rocket. And bells.



So a few threads to read about thoses solutions.


http://donkey32.proboards.com/thread/511/adventures-horizontal-feed if pics don't show, click on the blue links next to the crosses.

Cheap beels anf flue as the half barrel system.

http://donkey32.proboards.com/thread/560

Still on the half barrel.

http://donkey32.proboards.com/thread/609/heated-seating-nyc-restaurant

Worth checking his photobucket album for a better view.

My latest take onto a mobile'ish half barrel.

http://donkey32.proboards.com/thread/833/tube-incher-bell-volume

My "mobile" batch rocket.

https://permies.com/t/17600/wood-burning-stoves/Ernie-mad

Well, hope this helps a bit.

the half barrels they are using - what is on the floor under the barrel when it is inside? I see outside he is doing it on the ground, but how does he go inside safely?

Jay, many things can be done. Set the bottom of the barrel in cob, concrete, earth, sand etc You could also weld steel. I don't know what are your means. I have a crane, a pallet truc etc. So i can move heavy things. But you could put chipboard on the floor, for example, build a wooden box around, like Matthew did. Or make a complete wooden box/crate. Chuck some earth or cob at the bottom. Or make smaller one half barrel boxes. which can be joined together with tubes. Put cob, or earth, concrete or sand, whatever you feel like on top of the barrel. I want to cover the barrel, so i don't kave to burn the paint, myself. But you could use gravel, if you burn the paint. Fist sized stones, so there's convection of air in between thoses. Instead of gravel. In your box, you can go up just barely above the barrel, and fit pavers on top. This makes the base unit more moveable. Tho, remember, all this is not light. About 260 kilos for each base unit made out of clay, i'd say, at the lightest. That 100cmx65cmx35cm with a half barrel fited in it. You might want 6 of thoses in a row. That's already a ton and a half. Plus pavers on top, lets say two tons. Would your floors, over 20' lenght cope with this?

Forgot to show you this one.

http://technologieforum.forumatic.com/viewtopic.php?f=19&t=27

More bell than mass.

First, my cows are not appreciative of my new interest in RMH and bells - I was an hour late to milking because I kept watching video clips and trying to understand the barrels, exhaust location, burning chamber size etc (my brain doth spin!)

Neither I nor my husband weld and we have no crate or pallet truck, but our lives are full of lots of physical work and lifting so moving cob, earth, sand etc is not hard for us. And we have a 1 ton truck that can haul dirt and a tractor.

What about the concern that the wooden box will burn? Several people asked that and I did not feel it was answered too adequately (we'll be checking next year etc). It looked like there was maybe 2-3 inches between the half barrel and the wood.

The location this stove is going in has 2x8 or 10 x14 foot floor joists every 12 inches set on top of a couple of lengthwise running metal i- beams (I'll get DH to crawl under there next time he is there to see for sure how wide the floor joists are apart). These places are moved in 2 - left side that is 14x80 is hauled in first and then the second 14x80 is attached on the other side. They are usually blocked with concrete blocks and I know the entire house is on a concrete pad. I know that due to the metal beams running the long length of the house and no strength on the edges, you aren't supposed to put these homes on a basement.

The stove would be running parallel to the floor joists which is probably a big problem as no 2x10 will hold several tons of weight. I was going to put it along a wall that faces the living room and kitchen. The wall is 14 feet long and runs north south. I am glad you asked these questions as I had not stopped to think how the direction I wanted to put the RMH was vs. the floor boards. The problem is that the walls running east west across the joists have windows all across them and those windows are only 12 inches from the floor. I'll have to figure out what to do to get around this. I could put it in the middle of the room so I could go east/west but then the ceilings are tall and I didn't want to run pipe 20 feet up through the ceiling.

It doesn't have to be portable, but it does need to be able to be moved OUT if the next owners want it gone before we leave. I'm seeing a few things - old lockers, metal trunks etc that people are putting the barrels in that might work. The reason I like the idea of barrel is a lot less weight on the floor but I know one must be sacrificing something for that mass?? Are these things heating as well as the traditional RMH?

Has it been determined that the horizontal exhaust is a thing of the past? My initial research showed a horizontal exhaust and now I'm seeing all the new plans are vertical. And I believe I read in a post a while back that Ernie and Erica abandoned the horizontal, but I need to do some more research on that. I was HOPING to go out horizontally and have an external vertical if necessary - we don't want to put a hole in the ceiling yet because we are finding that nobody here likes to burn with wood and that means they also dislike holes in their ceilings from the chimney box. Their grandparents were forced to burn and heat with wood and why would they want to go back to that!
Edited to say I just found a post Erica wrote on vertical vs. horizontal and she answered most of the questions. But share your critiques if you like! They must feel the half barrel and barrel bell ideas to be not as good as their RMH? (not wanting to start an argument at all, just curious if they would recommend using something like a barrel).

I have only seen half barrel boxes so far - are people doing full barrels also?? I am not at all opposed to that if it is better (there is TONS of room in this house for anything I want as we don't use a lot of living space).

Are the tubes joining the half barrels at the bottom still? And tube does the diameter of the joining tube matter (6 vs 8 etc)

Is this what you are referring to http://donkey32.proboards.com/attachment/download/345

If so, they are making solid wooden boxes, putting a few inches of cob, concrete etc under the barrel, covering barrel with a good layer of COB to not burn paint, then fist sized stones on top of the COB? Then topping it with pavers? Is this air space with rocks better than some type of fill or more COB? We happen to live somewhere there are very few rocks - very fertile ground and such. It is probably easier to get pea gravel or even to do COB than to locate fist sized rocks.

Jay, if on a concrete slab, may be you could reinforce the joists with legs. Then if done properly, it would hold anything pretty much.

About the wooden boxes, i haven't tried, just done the last drawing you've posted to ilustrate the concept. Wood boxes should be all right with the mass, as it shouldn't go much over 65C° (149F°)

www.doctorfire.com/low_temp_wood1.pdf

www.fpl.fs.fed.us/documnts/fplmisc/rpt1464.pdf

Plus the thing being the hotest when you use it, and being on sight should be all right. If you have clay in your soil, i'd do half barrels in boxes 2 inch of clay in the bottom Make the box three inches at least wider and longer, than the half barrel. Then cover it with clay/cob wet ramed earth. Well, what you have the cheapest and most convenient. Make the box so that it is 4 inches higher than the half barrel (58cm/2 So it's 29cm, nearly 12 inches high for a half barrel) And then you have a layer of 2 inches below, 2 inches above. Then you could put pavers on top. Or go a bit thicker on the cob/clay above and skip the pavers. Less risk of cracking. About the height of the intake and exhaust of each part, depends. If you want each one to act as a single bell, or as separate bells. Bottom intake and exhaust at the begining and the end of the mass. Top conexions for single bell, bottom conexions for separate bells. http://www.stove.ru/index.php?lng=1&rs=16.

About full barrels, i think i've seen it used as a bell once, covered with cob. But only one. Peter van den Berg has on his batch rocket, a stack of two barrels on top of each other, making a big bell. No mass.

I've given up the metal trunk idea, just because of cost. I wanted new ones. Lately i've bought a huge flower pot to house the rocket core for my next project. http://donkey32.proboards.com/thread/836/flower-pot-suitability

For bells, plenty of other things can be used. Since you're farming, you must have seen thoses old fuel tanks to refill the tractors? You know the old metal ones rectangular in shape. They could be used as a bell, two tubes goint in and out at the bottom, and exhaust of the stove going in, then the exhaust of the bell going into a chimney. With bricks dry stacket all around the bell, heating by conduction. Pavers or bricks on top. They can be put in a normal fashion for maximum mass, or as a latice for less weight and quicker heat. This one would be pish easy to do. Just requires lots of bricks. Or even concrete blocks. If they don't hold on their own. They can be held by chickenwire, wire mesh, mosquito mesh.

Plenty of other things can be used, like french concrete washtubs. They just look like a seaty on it side Close the top, lean it upwards, and voila, instant sofa bell http://www.google.fr/search?q=lavoir+b%C3%A9ton&hl=fr&rlz=1T4ADFA_frFR472FR472&tbm=isch&tbo=u&source=univ&sa=X&ei=HhQRUs2SKY6r0AWE7YHwDA&ved=0CDEQsAQ&biw=1243&bih=519

Well, hope all of this gives you a better idea of where to head.

Oh, i forgot, horizontal flues are a pain in the A..... Bad smokeback with the wind.

Jay Stegman : Please go to our sister site richsoil.com and Click on Rocket Stoves, in this series of videos you will learn how to condition a barrel,
you will have to modify the technique for 1/2 barrels but this should be done before moving them into the living area, this does soften the barrels temper
some, and should make it a little easier to cut your barrel in 1/2 if you decide to go that route ! I am also concerned about the amount of heat that will
be radiated out the bottom, when you get 'The Book' Read the FIRE ! FIRE ! Section ! and good luck ! Big AL !

I am probably the most afraid of fire, out of control, burning a house down, burning a field down, (burning anything including grass!) and so if there is ANY question about it overheating the floor it will be out. Thank you for cautioning me though as many a person wishes they had been warned!

In re. to the half barrel theory - I'm not seeing the inside of the batch barrel to understand how it works without a J inside? If the diameter of the burn chamber, tunnel etc is all so precise, how can you just have a large feed chamber that breaks the rules of size and has no horizontal combustion chamber ? I saw from the one diagram they were still insulating and forming a J cast core and then utilizing the half barrels further on, but the Matt something or other that was linked to doesn't appear to have anything like that in his outdoor stove. (obviously it was outdoor and not necessarily done safely for inside a house)

Jay Stegman : The batch burn Rocket is totally outside my wheel house, and I can not be counted on for comments on the whole thing besides some healthy skepticism.

I Know that this Rocket can be made to work, but it definitely needs more masonry skills and close following of details, that makes a Conventional R.M.H. build seem as
simple as a ring toss. I would council for a 1st build to follow the conventional building plans, and then adopt one change at a time ! But then again some of my reluctance
may be a fear of the unknown ! Advice is usually worth exactly what you pay for it ! Run your own race ! For the Good of the Craft ! BIG AL

Jay.

According to Peter, the bottom of a bell doesn't heat much. If worried, make it thicker, it will take more time to heat.

Well, the half barrel system is a bit weird for Matthew's outdoor system. He uses it even for the burn tunel.

Latest version.



Batch rockets are L type rockets, not J type. But still have stringent shape rules. But are doable no doubt. It's a L shape with a bigger box, and a kind of "venturi" at the back of the burn tunel. Advantage they have, they output more heat, and don't have to be fiddled about much fueling wise. And can be loaded for a while without going out. May be you can come back every hour, hour and a half.

Look at Sandy's Chimney flue bells numbers.



Max temp, 140F° aproximately at the hotest point, on top of the bell. Frankly, i don't see that as a fire hazard.

So continuous work on a regular RMH would be stoking it a lot the first while - maybe more than every half hour. With a batch maybe every 1.5 hours. I might have to figure the logistics of running one, as it takes us 1.5-2 hours to complete our chores morning and night, and I can't see me remembering to run to the house to stoke it every half hour for a few hours. OR are you guys doing a 6-8 hour feed and then letting it go for 24 hours ish? I'm sure it is like so many other things we have done and just simply takes getting used to and planning your life around it which is NOT a problem for me.

Do others ever install a regular wood stove for "backup" and immediate heat when the stove has completely cooled? For example, if we are gone for the day or a 24 hour period, I would not have time to get up, watch the RMH for 2 hours and then do chores for 2 hours and then go to town (a 1.5 hour drive one way). We do a day trip like this once a month for supplies. Or how about if you visit somebody for a day, how do you run your stove in preparation? I am a bit of a hermit so we don't do much outside of our acreage, but it does happen Our wood stove right now takes about 1/2 hour to get going well (I do baby it when first starting it), then I can usually do a good stoke that will burn all day and when we get home at night it will still be warm. It is the -50F windchill days that are seriously hard. But it gives us immediate heat if we need it.

I am thinking of doing a few things. WHEn the book comes I will make a small outside model to give me an idea of how the feeding works, how it maintains heat etc. I would love an outside one like the video (that video is actually the one I was referring to when i said using a half barrel as the burn chamber), but until I am very sure of the temps, heat and logistics I would leave the experiments outside. I have more than a healthy fear of fires so the idea of burning a hole through my floor from heat freaks me out (Already been there raising chicks inside my house when it was -10 May 4th). Until i am much much more knowledgeable of all the logistics like you two fellows I won't fuss with it, but I do think working with outside models will be great learning experience.

I am still confused on using one to heat a greenhouse as I can't imagine having enough time to continuously feed a fire in a greenhouse every day, but I love the idea. Last place we lived we had a pit greenhouse that was killer and my favorite place to be on a -40F day.

Out of curiosity, where are people getting these 17 gallon barrels? I've never seen anything other than 55 gallon.

Satamax, is there a book out there specifically on these barrel and half barrel batch rockets with more specific numbers, using L instead of J etc? I'm reading as much as I can on the multiple forums and reading the different websites, but maybe I'm missing something that would bring a lot of it together

In re. to vertical exhaust, is there any problem with them freezing over because of condensation? this last year we had record cold temps forever and all of our exhausts in the house (bathroom, furnace etc) froze up every night! Lots of fun climbing up onto the roof to yank them out, thaw in the house or jam a broom handle trying to break it up. It only takes a short while to freeze things solid here!

Book, nope, you will have to read read and re read the hirizontal feed thread at donkey's board. All the dimentia and proportia are in there.

Don't know about the freezing. Barrels, ffor the half barrel mass system, they use 55 gals. But 17 might be found at auto mechanic shops. Usual for weird types of oil.