My first RMH

This is my first attempt at a rocket mass heater yes it's in a mobile home on a wood floor however the floor has been reinforced and extra layers of heat protection on the bottom especially under the burn chamber. This is a dual stratification style bench with a batch box and a 6in exhaust granted the batch box is is a bit small. The idea is when finished there will be a concrete countertop over top the whole thing so that only the barrel will stick out of the countertop by about 2 in making a nice cooktop built into the kitchen counter. Also it's still quite ugly right now but I will pretty it up come summer I had to improvise the top stones on the bench I was going to cast my own concrete but it got too cold too fast and it's going to take too long so I will redo that part come summer. The wood Shelf will pre dry the wood as it's directly above the burn chamber I intend to make a removable stone door on that shelf so that it may double as an old school bread or pizza oven not sure that will work out can't tell exactly how hot it will get until I fired up
I have named it calcifer after the fire from Howl's Moving Castle I intend to incorporate the name somewhere on it

Do you have to double skin the stratification chambers?

Hi Ryan,  Thanks for posting pictures of 'Calcifer' the fire breathing dragon. A welcome addition to any good home.
I do however see 3 things that could cause some problems for you
1) Your manifold (the hole in the fourth picture that gets covered by the barrel) looks quite small. The transition from the barrel to the bench needs to be much bigger to keep this from being a bottleneck area. As big as you can make it. 150% of system size minimum has been recommended.
2) Your bell benches may have too much ISA (Internal Surface Area) for a 6" system. Without having any dimensions to confirm this, I can at least say that startups are probably going to be tricky without some kind of bypass or assistance from a fan or small flame under the vertical chimney. Perhaps you have already worked this out, if so great.
3)The flexible pipe coming out of your second bell...is this temporary?
Look forward to your progression and putting the skin on your dragon. Send lots of photos. We all like them.

Hi Ryan; Nice start on your first RMH!
I do agree with Gerry's observations. Especially #1
That transition from the barrel to the manifold must be large enough or it will give you problems. Yours looks to be 6" ?
Were you following dimensions from Peter Bergs website ?  If I remember correctly a 6" batch will allow 57 SQ FT of bell.  I could be wrong on that number.
Flex pipe is known for resisting smooth flow and is not recommended.

Your build in progress is messy but the bones of a solid dragon are there!
Give us some numbers to guide you towards a successful first flight of your dragon!
And keep the photo's coming !

What did you do to reinforce the floor? We live in an old house with a quasi-finished basement and I am trying to figure out how to support the floor in the living room where I'd like to put the RMH so the floor will hold it. I was thinking of using those metal pillars under the part of the floor where we would put the RMH. I forgot what those pillars are called exactly. Is that what you used?

Wonderful to see someone else working to build a RMH in a mobile home!  I did this as well late last fall in my small mobile home, however, I did a pebble style.  I'm thinking of trying to convert mine to cob since I believe the floor could take the weight.  When I wiggled under my trailer to brace the floor I noted that my long bench centered perfectly along the length of one of the trailer's main I-beams!  In this way I think it worked out better than doing it on a wood floor in a traditional home, of course that's just a guess on my part.  Because it was all under the I-beam I was able to give extra bracing to the beam with just some cinder blocks and wedges.  Part of me still wonders if the floor will suddenly collapse one day, and I'm willing to accept that risk to try this out as I figure I'd be able to rebuild the floor myself.  So far, one year later, I haven't seen any issues with the floor sagging or showing signs of giving way.

I look forward to seeing how Calcifer progresses and performs!  I have thought that perhaps a stratification chamber should be something for me to try too.  My problem is that my trailer, and the room configuration, is too small to allow me enough traditional heat exchange bench length to fully draw the heat off before sending out the chimney.  Thus mine is of rather "poor" efficiency for a RMH.  I "only" cut my wood use 50 to 55 percent and my propane use 80 to 90 percent.  :)  It would be nice to lower my wood use even more.  In my dream world I'd get below half a cord for a winter.  Right now I expect to be between 1 and 1.5 cords.

Annie Collins wrote:What did you do to reinforce the floor? We live in an old house with a quasi-finished basement and I am trying to figure out how to support the floor in the living room where I'd like to put the RMH so the floor will hold it. I was thinking of using those metal pillars under the part of the floor where we would put the RMH. I forgot what those pillars are called exactly. Is that what you used?

I believe those "pillars" you are talking about are called floor jacks, but I'm not certain.  I thought I'd have to use them under my trailer for my RMH, but in the end my crawl space was so short it was really a wiggle space and I was able to use cinder blocks, scrap wood, and some wedges.

David Huang wrote: I believe those "pillars" you are talking about are called floor jacks, but I'm not certain.  I thought I'd have to use them under my trailer for my RMH, but in the end my crawl space was so short it was really a wiggle space and I was able to use cinder blocks, scrap wood, and some wedges.

Yes, floor jacks, that is what I meant. Thank you! I think if I put enough of them to support the floor, there should be no problem. Thank you for sharing your stories. It is giving me more courage again to consider building a RMH in our rather old house (with enough supports).

Hi Annie;   2 Jacks with a beam (wood or metal) to support the floor joists.  This will support your floor. Weight of a solid mass is similar to a king size water bed.
Have you considered using a bell (stratification chamber)  instead of a piped mass?  Weight is much less.
In my opinion, a bell loses its heat slightly faster than a solid mass but in an insulated home only on the coldest days might you notice.
 

thomas rubino wrote:Hi Annie;   2 Jacks with a beam (wood or metal) to support the floor joists.  This will support your floor. Weight of a solid mass is similar to a king size water bed.
Have you considered using a bell (stratification chamber)  instead of a piped mass?  Weight is much less.
In my opinion, a bell loses its heat slightly faster than a solid mass but in an insulated home only on the coldest days might you notice.
 

Thank you, Thomas, for the tutorial on the support! I am planning on building the bell chamber version. As you said, it weighs less, but it seems a lot less work to build, too. Since I will be building this on my own, the less work, the better. :-) I am planning to buy one of Matt's, from Walker Stoves, plans. Getting excited now!

As for my floor reinforcements they are 5,000 lb scissor jacks and there's four of them with with a 4 x 6 on either side please note there is a 6-inch concrete slab that the house sits on if you have dirt under your mobile home you may want to use more than just a 4 by 6 to combat sinking into the dirt  also for reference I think mine totals out at somewhere in the neighborhood of three tons my suggestion do not skimp on floor reinforcements also especially in a basement put something under your reinforcement if the wait is too focused it will crack your basement floor over time so spread it out with a piece of steel or heavy wood

As for the pipe going from Barrel to bench it's only 6 in apparently that's a detail that I missed but seeing how it's literally set in concrete I don't foresee it changing though I don't see how a 6in riser is going to feed more air than a 6 inch exhaust can handle especially considering I have a small batch box but we'll see I've done small-scale Burns in it at low temps just a few pieces of cardboard and it seemed to be working just fine but it's too early to say for sure
And yes the aluminum dryer vent is temporary it's going to go out the window they're above it but right now it's just sneaking into the standard fireplace that came with the house just haven't gotten that far yet
As for under the Firebox to protect the wood floor there are two layers of firebrick two and a half inch of concrete two healthy layers of high temperature mortar about a quarter inch thick and 8 layers of sand and tin foil to create some air gaps also keep in mind being that it is a mobile home and some of the insulation has been removed below it the underside of that wood is essentially being refrigerated and it's hardwood so it should be able to withstand around 250°
And no I'm not exactly a stonemason so yes my motor work is sloppy as hell but it's working fine the first ratification chamber doesn't seem to have any leaks someone mentioned some kind of inner lining could you elaborate
Also I'd like to point out that this entire home runs on solar as well with a 5kw lithium battery

Great choice Annie !   Matt is a true rmh professional. His plans are top notch, and  he will guide you thru any questions/issues you might have.
Please document your build with pictures as you go.  
That will help other first timers feel confident about building their own.
Feel free to ask us for help as well ... we have a cheerful crew of rocket scientists eagerly awaiting your questions!

David Huang wrote:

I look forward to seeing how Calcifer progresses and performs!  I have thought that perhaps a stratification chamber should be something for me to try too.  My problem is that my trailer, and the room configuration, is too small to allow me enough traditional heat exchange bench length to fully draw the heat off before sending out the chimney.  Thus mine is of rather "poor" efficiency for a RMH.  I "only" cut my wood use 50 to 55 percent and my propane use 80 to 90 percent.  :)  It would be nice to lower my wood use even more.  In my dream world I'd get below half a cord for a winter.  Right now I expect to be between 1 and 1.5 cords.

There are other options you might be able to use to increase efficiency for example replacing a wall or simply a tall thin duct Style heat exchange or even a simple dragon pipe I at one point and also considered having some sort of heat exchange go beneath the trailer to provide more even heat around the house though I'm not sure how will the thermal safe and we would react to that much of a drop

David Huang wrote: I have thought that perhaps a stratification chamber should be something for me to try too.  My problem is that my trailer, and the room configuration, is too small to allow me enough traditional heat exchange bench length to fully draw the heat off before sending out the chimney.  Thus mine is of rather "poor" efficiency for a RMH.

David,  The great thing about bells is that their shape is not as confining as a piped system. In other words, if you don't have the space to go more horizontally, you can always go UP.
As you may know, bells work through stratification which translates to, the more vertical ISA space your bell occupies, the more room it has to stratify. So really, a bell can take up much less of a footprint than a piped bench can if you don't mind a tower in your house. It could also be some bench and some tower too. The best of both worlds if that's what your looking for. Anyway, something to consider.
An example from Dragonheaters.com:

thomas rubino wrote:Great choice Annie !   Matt is a true rmh professional. His plans are top notch, and  he will guide you thru any questions/issues you might have.
Please document your build with pictures as you go.  
That will help other first timers feel confident about building their own.
Feel free to ask us for help as well ... we have a cheerful crew of rocket scientists eagerly awaiting your questions!

Thank you, Thomas Rubino, for your encouragement and positive attitude! I will definitely document as I get started and continue as I go along, and will ask questions if needed. Great pictures of the scientists! Gave me a good laugh. Looks like one group will be good for building help and the other perhaps for celebrating once we get a good first burn going! :-)

Hey Ryan, loving how your bench is coming along. If you need help I live pretty close to you amd wouldn't mind seeing it first hand! I completely forgot I messaged you back when you posted that windmill and how close we are in distance and age. (I'm 32)

My girlfriend and I are living in a 12x28' shome (shed home) over in Copemish and are considering different wood heating options.

Also, Howl's Moving Castle is one if our favorite movies and I am currently in the third book. We just took in a couple stray kitties in October and our son named the orange and white one Calcifer.
Anyways, let me know if i can help or if you are interested in meeting up at all.

Joshua Radish wrote:Hey Ryan, loving how your bench is coming along. If you need help I live pretty close to you amd wouldn't mind seeing it first hand! I completely forgot I messaged you back when you posted that windmill and how close we are in distance and age. (I'm 32)

My girlfriend and I are living in a 12x28' shome (shed home) over in Copemish and are considering different wood heating options.

Also, Howl's Moving Castle is one if our favorite movies and I am currently in the third book. We just took in a couple stray kitties in October and our son named the orange and white one Calcifer.
Anyways, let me know if i can help or if you are interested in meeting up at all.

Absolutely down to meet new people especially those into this type of stuff  my cell is 313 969 7684 feel free to txt any time id love to chat    and yes im cool with shareing my number you can find me on face book or kik as well  the name sleep is rather easy to find

UPDATE just got the heater up and running at full temperature for the first time today and it seems to be working very well the barrel is reaching 700 degrees and the bench is a hundred degrees all the way to the end the dryer vent is surprisingly only about 80° and the smoke coming out I can literally put my hand in front of it and it's barely warm

My only concerns at the moment or I'm getting a bit much backflow granted it was just my first start up so I expected to get quite a bit once it got up the temperature it was down to next to nothing and I'm using a makeshift door that is far from sealed just probably a quarter inch Gap all the way around sometimes when I put a new log in there it will smoke out of the door for a minute or so but that's it

UPDATE the next morning: on how long the mass lasted  we turned it off at about 6 last night we just wait earlier than we intend to do on a regular basis but it was our first run but it was 25 degrees out last night and this thing is in a 1200 square foot mobile home with a very open floor plan the main room which is probably at least half of that square footage is what it is mostly intended to warm it was 72 degrees when we turned it off and the stone was around 100 to 120 degrees everywhere from around the Firebox to the tip of the farthest point of the bench by 4 a.m. approximately 10 hours after the fire had gone out the bench was still slightly warm the room was still 55 degrees the drum was still surprisingly about a hundred and twenty degrees and the stone around the core was still around 90°       by 8 the next morning approximately 14 hours after the fire has gone out it was still 51 degrees in the house the bench was about 60 to 65 degrees and the stone around the fire box was about 80 to 85 degrees also for you mobile home owners of the underside of the house was still 38° with one of the access hole still wide open   I should point out this mobile home is not the best insulated mobile home that has the world's shittiest windows and this model was built in 1989 Scott wood paneling walls not even drywall
As for my second attempt to light it the next morning it seems to be going far better than the first time with about 60% less backflow coming out the door and it lit up first try this time has the fire chamber was still quite warm

Hi Ryan;   Sounds like you got yourself a dragon!
It will get better and better as it drys out.

Gerry

I'm beginning to think you might have been right about that 150% times the size for the manifold exhaust into the bench I am having an unacceptable amount of backflow into the house from the fire chamber I'm going to try making a fairly tight door and making a larger lip on the top side of that fire chamber entrance hopefully that will help
 as far as making that exhaust bigger the only way I can do that is with my cement drill and it's only going to get slightly larger and it would be an enormous pain in the ass and take an awfully long time and I've already got snow

Hi Ryan,   Sorry to hear your having problems.  Was wondering if your batch rocket was built to the specs on Peters site Batchrocket.eu or it you just winged it?
Another bottleneck area is the top gap. Batch boxes require much more space than J tubes do. Off the top of my head I believe its a minimum of 12".

Gerry Parent wrote:Hi Ryan,   Sorry to hear your having problems.  Was wondering if your batch rocket was built to the specs on Peters site Batchrocket.eu or it you just winged it?
Another bottleneck area is the top gap. Batch boxes require much more space than J tubes do. Off the top of my head I believe its a minimum of 12".

 

I believe the distance from the top of the barrel to the top of the Riser is something like 3 in that I could easily modify though but I have just now discovered a new problem I've only burnt to fires in this thing in my fire brick has cracked in 11!!! places
And no I just went off of YouTube videos did not know such specs existed  

Also my last burn I did a much lower temperature burning I only burning about One log at a time my temperature has dropped by about 200° off the barrel I figured a slow or longer burn might be safer and hopefully get away with the smaller manifold outfit

That many cracks would definitely make a difference in performance. Even if you don't make any major changes this year and are able to make it work to keep you warm this winter, reading through Peters site is really educational and worth taking seriously as he has put a lot of time into experimenting and coming up with a solid system that works.
The batch box is much less forgiving than the J tube when it comes to dimensions and how to run it so that it produces a clean burn. They were never intended to run only single logs at a time, but rather (as the name states) in batch loads at a time.
Stay warm!

Gerry Parent wrote:That many cracks would definitely make a difference in performance. Even if you don't make any major changes this year and are able to make it work to keep you warm this winter, reading through Peters site is really educational and worth taking seriously as he has put a lot of time into experimenting and coming up with a solid system that works.
The batch box is much less forgiving than the J tube when it comes to dimensions and how to run it so that it produces a clean burn. They were never intended to run only single logs at a time, but rather (as the name states) in batch loads at a time.
Stay warm!

Well I'm going to have to try the simplest Solutions first so I need to make a real solid door and I'm going to attempt an assist fan see if I can live through the winter like that and then fix it properly come summer if that doesn't work then I got to take off a barrel and take the top off one of the benches and start tearing up concrete which in no way is going to be an easy task and will likely take most of the winter anyway  

On a side note I find it strange that the high temperature mortar seem to hold up to the heat better than the fire brick itself and though the bricks cracked they're still solidly in place so I just filled in the cracks with some high temp mortar I had some extra and go from there

Where you stand now, simple is a good thing. Seal the cracks and raise the barrel for sure. You know, if your exhaust temperatures are too low to create a good enough draft because your extracting too much heat with the bells, then maybe the exhaust exit can be raised higher up so it captures more heat?
Also, I wonder if the cracks were a result of the firebricks maybe being wet and then heated too quickly?

Annie Collins wrote:I am planning to buy one of Matt's, from Walker Stoves, plans. Getting excited now!

Good idea.
Matt has some great plans and he’s super supportive on the development and back end of the build.

Good luck!

Peter