Plans for a whole house heating solution - Rocket mass heater design

Hi fellow premies!

I was reading, watching, listening to clever people's writings, videos, etc, on the net in a few years back, and deceided to build my own rocket mass heater.
I'd like to use it to heat my whole house with it.
Can you help me with some instrucions about it?  
First of all, this'll be my very first build, and plan is around in my head since i first discovered this heater kind.
The house all together is about 100m2 (square meters), made 75% of 60cm thick adobe tiles (wall is that thick not the bricks, lol) silly me.
Have some rooms away the area where the heater would be. The main of the heater would cover 4 rooms with the heat (hopefully), and add some water lines to it to make the non reachable areas warm.
okay, starting with the main question, how long the horizontal pipes can be? I think all together I have something about 15 meters maybe 17m long. and there would go to the brick cimney. (made of small bricks, 25cm by 12cm, by 6.5cm tall), and inner size is roughly 14x14 cms.
if i'd say to help imagine, the 4 rooms are differ in size, and share walls between them like an X lookd from above. as it is rn. lol
Does any of you have experience build, and planing heating this kind of layout?
I'd like to use mainly awailable things without breaking the budget, and use re useable materials, (earthmud, clay, sand, 55gal barrel (200L in eur measures, firebricks, normal bricks, no metal pipes, instead old roof tiles out of use, etc. Mainly DIYish cob. made by their video
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If any more information is needed, please let me know.
Any help, or advice would be greatly appretiated.  Thank you in advance.

Hi Peter.  

Welcome to Permies.

Sounds like you have a grand plan here and there are plenty of folks on this forum who will be happy to help you along.  First of all, let's get a better idea of your floor plan.  Is it set in stone?  Maybe you are in a position to maybe allow the whole house rocket stove heating system you have in mind help determine how the house is actually laid out in a "form follows function kind of way".  

My first reading of your idea had me visualizing a large brick bell attached to a J-Tube rocket core.  The large bell was centered on the spot where four wall intersect, giving each room a radiating bulkhead.  Are you familiar with bells or stratification chambers?  I think this would be ideal in your situation.  Either a large bell serving the radiant heat needs of four rooms or a large stratification bench built in the same fashion.  So that at least part of one wall in each of four rooms will have a radiant bench.

Embedding waterlines is doable (part of my plans as well) and as long as you embed them in a heated mass and not expose them to the hottest part of the fire you won't risk any steam explosions AKA  (Boom  Squish).  

It would probably help a lot if you could post some kind of drawing, no matter now crude to give us an idea of how you see your home and we can see where it goes from there.

Thomas Tipton wrote:Hi Peter.  
answer:
Oh! Dear Thomas! Hello!
I'm glad.
Thank you for joining in.

Welcome to Permies.

Sounds like you have a grand plan here and there are plenty of folks on this forum who will be happy to help you along.  First of all, let's get a better idea of your floor plan.  Is it set in stone?  Maybe you are in a position to maybe allow the whole house rocket stove heating system you have in mind help determine how the house is actually laid out in a "form follows function kind of way".  
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answer:
Yes, the things you've stated are valid. if im saying correctly. Sorry for my bad english.
It is above ground level, at least 80cm(at least the base of the house at that point), and it is on a thick but i think pretty old (some wall painting say 1955 as they renovated the house back then) , cement based floor is there. Dont know yet how thick it is. I have a drilling bit which is 45cm long. I'll try to check out how deep it goes. So its not stone to answer. If i understood correctly.
Sorry I'm just  really excited. was waiting too long maybe...

I made a drawing last year march, I'll try to attach here, changes are made, and it is going near the walls all longness.
(it looks like  tiles, and the way of the red dot which meant to be the barrell, and the star is the chimney)

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My first reading of your idea had me visualizing a large brick bell attached to a J-Tube rocket core.  The large bell was centered on the spot where four wall intersect, giving each room a radiating bulkhead.  Are you familiar with bells or stratification chambers?  I think this would be ideal in your situation.  Either a large bell serving the radiant heat needs of four rooms or a large stratification bench built in the same fashion.  So that at least part of one wall in each of four rooms will have a radiant bench.
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Answer:
So yes. A J-style rocket sotve or mass heater, with the barrell, and dont really know much about stratification chamber sizes. (converges to zero in personal physical experience) read some about Peter Van Den Berg stoves, but I am a kind of bull on the market guy, head towards walls, n' run like hell type, but this time I want to do it different. =) With the help of more experienced people around the globe. And hopefully if we might work together it'll became a sucsessful project, and show the people around that if they try to escape their "old communist" fashioned mindsets, and lack of knowledge (heating in stoves, and wasting resources out of their chimney ,or burned earth gas), giving them mostly 20% what they actually fired there are more efficient ways of heating.  
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Embedding waterlines is doable (part of my plans as well) and as long as you embed them in a heated mass and not expose them to the hottest part of the fire you won't risk any steam explosions AKA  (Boom  Squish).  
answer:
I'd like to lay the water lines Under the main lines outer of the wall side, but under where the wood gas exits the barrell, 2x 10m
maybe 4x 10m long 10mm diamter copper pipes with 90°angles, and 5 layered heat pipes, and put a pressure valve to the highest point and adding a maybe 20L "bucket" ("" because it is a barrell i think), for expansion of the steam.
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It would probably help a lot if you could post some kind of drawing, no matter now crude to give us an idea of how you see your home and we can see where it goes from there.

answer:
I hope my drawing is readable.
Thank you very much!
Lovely for helping out!
ps: almost forgot, will i be able to expand the space later, and till it be able to heat a probably 2nd floor upstairs, the size would be approx 60m2 inner height on the 1st floor is 2.8m and the 2nd would be 2.3 at max. Or will it be too much for that little guy?

To show how "mad" i am, I light fires from top. lol

"Set in stone" means a fixed, unchangeable plan

I see you have an existing house where you want to add a rocket mass heater. Thomas' idea of a single centralized bell or stratification chamber would be perfect for new construction, but obviously not for your actual situation. Do you want benches for sitting on, or would vertical masses work better for some or all of the rooms? Assuming you can't safely make more than small holes in the walls, you could do a series of bells one in each room with short channels connecting one to the next.

The J-tube location looks fine. Where would the wood be brought in? It is good to make the path from there to the fire as short as practical, to minimize carrying and mess.

To your question about a future second floor and being able to heat it, that depends largely on your climate. How cold do winters get? Do you have a lot of warm and cold days, or does it get cold and stay cold for days at a time? 100 m2 is around 1000 square feet, so easily heated by an 8" J-tube in a moderate climate. A second floor on top of that might be a stretch to heat. You say the walls are adobe, is there any insulation added? Adobe is great for hot days and cold nights, not so much for long cold spells. You might need a larger system, or an 8" batch box instead of J-tube. (A batch box puts out about twice as much heat as the same size J-tube.) Batch boxes are more complicated to build than J-tubes. You might start by building the J-tube, and see if it gives you enough heat without needing long burns. Make the layout so that you could change to a batch box later if you need to.

Glenn Herbert wrote:"Set in stone" means a fixed, unchangeable plan

I see you have an existing house where you want to add a rocket mass heater. Thomas' idea of a single centralized bell or stratification chamber would be perfect for new construction, but obviously not for your actual situation. Do you want benches for sitting on, or would vertical masses work better for some or all of the rooms? Assuming you can't safely make more than small holes in the walls, you could do a series of bells one in each room with short channels connecting one to the next.

The J-tube location looks fine. Where would the wood be brought in? It is good to make the path from there to the fire as short as practical, to minimize carrying and mess.

Hey Glenn! Thank you!

You and Thomas talking about the same? A bit lost here, sorry.  Why it is better a single bell for a newly constructed house?
I'd like to make the benches, to be able to sleep on them maybe, yes.  
You mean to connect the bells in every room? Wouldnt it means more wood needed, to feed all the bells? I  only want 1 place where im feeding the fire and it is near the entrance, about 2m away from the door.
Small holes in the walls? what is the meaning  of that? I'd like to make the way for the woodgas under the bench, all the way to the chimney. could you please explain?

Glenn Herbert wrote:To your question about a future second floor and being able to heat it, that depends largely on your climate. How cold do winters get? Do you have a lot of warm and cold days, or does it get cold and stay cold for days at a time? 100 m2 is around 1000 square feet, so easily heated by an 8" J-tube in a moderate climate. A second floor on top of that might be a stretch to heat. You say the walls are adobe, is there any insulation added? Adobe is great for hot days and cold nights, not so much for long cold spells. You might need a larger system, or an 8" batch box instead of J-tube. (A batch box puts out about twice as much heat as the same size J-tube.) Batch boxes are more complicated to build than J-tubes. You might start by building the J-tube, and see if it gives you enough heat without needing long burns. Make the layout so that you could change to a batch box later if you need to.

I'm living in the northern hills of Hungary, and the weather is sometimes (30 years ago) used to be -20 maybe -30 for a few days only .nowadays I only can say its almost getting lower than -10, and not for long usually.
Yes, adobe. No, there are no insulation yet. I plan in the next year hopefully to put on some reed insulation, about 8 maybe 10cm thick.
what is a batch box style? Is that the one that is vertically feeded, from the front?
If yes, i might be stay with the J tube first, as you recommended too.
Thank you!
About the waterlines under the benches, any recommendations, or ideas? Thank you!

Hi Peter;
A batch box is Peter Bergs's design.
https://batchrocket.eu/en/
Wood is loaded horizontally from the front and there is a door like a traditional wood burner.
Some metal fabrication is needed to build a door and a secondary air tube.
https://dragontechrmh.com/
A 7" or an 8" Batch would be a good choice if thinking of adding a second floor at a later date.

A tall bell with a sleeping bench would be possible using a batch box.
Building an 8" J tube and then switching to a batch box later is very common for new builders.
Here are my threads on building an 8" J tube with a brick bell and then switching it over to a 7" batch box.
https://permies.com/t/94980/Brick-Bell-Shop-Heater
https://permies.com/t/138779/Breaking-News-Shop-Dragon-admitted
Here is the shop stove currently
https://permies.com/t/190599/Finishing-touches-Shop-Dragon-rebuild

If you intend to switch you can make your bell larger at that time or you can build the bell for a batch box using size recommendations for the (ISA) internal surface area, including a bypass to allow heating of the chimney to avoid stalling (smoking out the house).

Thank you Thomas!

Before posting here, I've wrote to Peter but didnt get any answers yet.
those builds of yours are pretty interesting! Nice job!
Are they still in working order? thank you

A single bell is better simply because it is easier to build. The small holes in the walls would be for hot gases to travel from one bell to the next. There would be only one fire.

I think the best way to use copper pipes to absorb heat for pumping to remote rooms would be to embed the piping in the cob mass of the bench, so it will still be getting heat when the fire has been out for a while. I would probably locate it near the top surface of the bench so that it doesn't get too hot, not near the hot interior which may be well above boiling temperature.

Another way which would keep all the piping accessible for inspection or maintenance would be to expose a largish tank of water to the heat, and run your piping through that to exchange heat for pumping. This ensures that the pressurized piping never gets to boiling point while giving it consistent heating.

Well, the pipes under the gasway isnt the best spot i recon.

Thank you.

Looking at that floorplan.  In theory, he could build a bench that wraps around using only one penetration in the wall between the studs.  Unfortunately, the downside is there isn't likely to be any way to get enough heat to the other side of the house.  I don't think a J-tube is going to produce enough hot water to be pumped to the other side of the house past the kitchen.  Is there any existing ductwork in the house left over from a forced air system?  If there is, or it could be added, as long as there is electricity available he could use forced air to move heat over to where it is needed.

Thomas Tipton wrote:Looking at that floorplan.  In theory, he could build a bench that wraps around using only one penetration in the wall between the studs.  Unfortunately, the downside is there isn't likely to be any way to get enough heat to the other side of the house.  I don't think a J-tube is going to produce enough hot water to be pumped to the other side of the house past the kitchen.  Is there any existing ductwork in the house left over from a forced air system?  If there is, or it could be added, as long as there is electricity available he could use forced air to move heat over to where it is needed.

Thank You Thomas!

Can you explain what do you mean one penetration in the wall between the studs? on my floorplan, can you show it?
We discussed above that area is need to be heated by water tubes, installed within the cobb, with a self circulating the heated water by itself, and get radiators on there. (maybe with water pump)

21cm inner diameter. Will this be goo for my riser? How long should it be?

Hi Peter;
Yes, 21 cm is a good size for a riser usually around 122cm tall (48") but each build is unique and the height may vary.
Be aware that the pipe will need insulation around the outside and will only last a season or three before badly spalling and needing to be replaced.

Hi Peter.

What I mean by "penetration" is the hole you would need to put in your wall in order for the bench and bench bell flue cavity to pass through the wall and into the other side.  Basically, just a hole in the wall for your bench bell to pass through.

Jumping in with some hot off the press news about Rocket Mass Heaters from Permies.

The new free heat movie trailer is here starring Rocket Mass Heaters at center stage:

For more info, also take a look at https://freeheat.info

thomas rubino wrote:Hi Peter;
Yes, 21 cm is a good size for a riser usually around 122cm tall (48") but each build is unique and the height may vary.
Be aware that the pipe will need insulation around the outside and will only last a season or three before badly spalling and needing to be replaced.

Can you explain this a bit more--you mean pipe carrying steam from one cob mass to another will spall? or are we talking hot air? are you saying that the pipe in any rocket mass heater mass will spall like this??  I'm losing the thread here.

Any updates Peter?

The 21cm pipe is for the heat riser, where it would see extreme heat. Pipes/ducts in the mass will never see that kind of hazardous temperatures.

Glenn Herbert wrote:The 21cm pipe is for the heat riser, where it would see extreme heat. Pipes/ducts in the mass will never see that kind of hazardous temperatures.

Thanks for clarifying.

And is 100 Fahrenheit enough to cause a steam explosion?  Or is that just if the water is heated directly by the barrel instead of the mass?

100 Celsius would cause boiling in an open vessel; a closed pressurized vessel would go hotter before flashing to steam. 100 Fahrenheit would just be nice and warm.