|
Post by briancady413 on Feb 2, 2020 11:58:26 GMT -8
I'm interested in building a successful rocket mass heater heating a Korean Ondol-type stone and clay 16' by 16' floor for a 16' by 22' cabin. I intend to burn wood efficiently, thus quickly, then store the resulting heat in stone, clay and tile within the floor. I plan on the air intake being the lowest opening, with the exit from the smoke-burning area just above that, (below a smoke-burning space), and the floor above that, with a to-chimney exit as the highest opening just below the floor. This is to guide smoke release. Smoke exiting down from the heat riser/bell would, in plan, go up to warm the stone, clay and tile floor, then out a side escape into a chimney.
As I plan on super-insulating the cabin, I think I should size the RMH on the small end; say 3"/75mm diameter heat riser. I plan to use dimensions from: batchrocket.eu/en/building#dimensionI haven't made or witnessed Rocket Mass Heaters or Ondol systems working yet.
I would be grateful for your thoughts and advice,
Brian - PS: Plan to build this in Western Massachusetts, in a climate with around 6000 heating degree days
|
|
Bram
New Member
Posts: 45
|
Post by Bram on Mar 22, 2020 11:55:26 GMT -8
Hahahah, I came to this forum to discuss exactly this concept! Thank you for getting the ball rolling briancady413 We are planning to build a small office / workshop building. It will be an octagon and hopefully have a small mechanical workshop underneath. The office will be mostly used by my wife, who is a psychologist. She doesn't work every day of the week, and we have been talking about clustering all her appointments together into one week out of the month. That way she can have more free time the rest of the month. The clustering would help with how we heat the office as well. If we do go for an Ondol or Hypocast kind of heating I want it to run solely on prunings from the grapes and olives. Right now a lot of those kinds of branches get burned in this area and I really disagree with that practice. The design should incorporate a means for huge piles of tiny branches to be stuffed inside and lit all at once. Total floor area is gonna be around 20m2. I'm thinking to do a concrete slab for the ceiling of the basement, which is a requirement by law either way. This would allow me the freedom to either make that the bottom or the top of the Ondol. I'm thinking the bottom because I mostly want this floor to heat up quickly when we need it, rather than slowly and retain heat over a long time. But I'm open to suggestions. If we do make it the bottom I could have the slab run at a slant towards a gathering point, so it will be easier to clean with a water hose. I would then build a raised floor on top of that which would be heated up by the smoke passing underneath. What this floor would be built out of is up for discussion still. Could be another concrete slab or it could be other materials. As for the type of RMH to use, I think you are right in thinking about a batchrocket. But I want an even bigger batchbox, maybe a 80 by 80 cm or something. Might have to do an arch for the top. And I wonder if it will scale to that size. peterberg , any input on that? I didn't quite understand your description of the mass you want to use. Here's how I see it: The best use of this tech would be to incorporate a Bell to manage the smoke, similar to what is shown in this youtube video: www.youtube.com/watch?v=tx0BnCsYeXYWas that the kind of design you were thinking about? Forcing the smoke to enter a space where it can hang out until it has given off its heat and cooled down enough to exit through a LOW exit point. Preferably lower than the entrypoint. As an aside, keep in mind that no matter if your floor is going to be set into the ground or raised above the ground, its best to insulate all the way around it using styrofoam or some other non-rotting insulation. At least to 80cm deep if you are doing a 'floor level' floor. I believe this is called 'skirting insulation' but I could be wrong. ------ Here's a mockup of what we're thinking: photos.google.com/album/AF1QipN1rjIlVAiASw2IRbe94_NUWWXmPHHKffkNrPmO/photo/AF1QipOiFJ8vQltNuanANwSXr9to2Bu5X7IiQt9fskBGIt'll have the obligatory reciprocating roof photos.google.com/album/AF1QipN1rjIlVAiASw2IRbe94_NUWWXmPHHKffkNrPmO/photo/AF1QipPiPbB8atwUQ7BEMGGbGdnxrvqAt3QSsI4_loxPAny future pictures of this project will be uploaded here (if its pretty much empty that means the project died with this post ). photos.app.goo.gl/HPn3nVuGVGH7TjNk9
|
|
|
Post by esbjornaneer on Apr 3, 2020 5:43:50 GMT -8
Hi Brian and Bram, If you are thinking of heating the whole of the floor you will need a mammoth heater! Have a look at the recommended ISA's for Peter's heaters here donkey32.proboards.com/thread/1822/sizes-single-bell-systemsSo to get to 20m^2...? and that is before you count the wall of the bell under the floor. Good luck
|
|
|
Post by briancady413 on Apr 18, 2020 15:37:40 GMT -8
Hi Brian and Bram, If you are thinking of heating the whole of the floor you will need a mammoth heater! Have a look at the recommended ISA's for Peter's heaters here donkey32.proboards.com/thread/1822/sizes-single-bell-systemsSo to get to 20m^2...? and that is before you count the wall of the bell under the floor. Good luck Esbjornaneer, thanks for the response. While I'm thinking of heating the whole floor, I intend to heat it just a little bit. I imagine the bell upstream of the floor, as the ISA to consider. Then I imagine heat flowing in exhaust up to under the floor. What do you think?
|
|
|
Post by briancady413 on Apr 18, 2020 16:16:52 GMT -8
Hi Bram,
In 'Masonry' 1997 Taunton Press (ISBN 1-56158-214-X), pg 58 there's an article entitled 'K'ang: an under-the-floor masonry stove' by Jeffrey J. Smith, writing about the masonry work of Karl Marcus, who covered his masonry stove with a 4" cement slab. I imagine that would take along time to heat, although I'm considering 8" of stone and clay above the smoke path on this ondol concept. I imagined basalt 16"Wx16"Lx2"Thick slabs with their corners resting on basalt columns ( Basalt to withstand direct flame).Above that 2" clay to seal and store heat. above that 2"x16"x16" generic stone slabs, placed so that their corners were centered above th emiddle of the basalt slabs below the clay. Then soapstone 2"x16"x16" with it's corners cenetered above the middle of the generic stone slabs. Maybe I should rethink it all. Hmm. I had thought to use four 2" thick layers, bottom-to-top: basalt,clay, stone, soapstone. Maybe I should use 1" thick layers.
I guess it's possible to calculate how much heat would raise a mass by a certain number of degrees.
I like the firing with prunings idea.
I'm considering insulating the floor of the smokepath chamber with agricultural vermiculite, tamped into place I guess. It's fairly cheap, heat-proof and insulating, I think. From the interweb: "Type of insulation, R-value per inch of thickness. Vermiculite, loose fill, 2.08. Perlite, loose fill, 2.7...." Well, maybe I should use perlite. Lately I'm thinking of heating all this while making biochar using a TLUD canister and a smoke burning bell above it. This would burn slowly, completely changing what needs to be withstood within the floor flue. that might ease things.
Where are you at with all this? Gotta check your links...
Having no experience with rocket heaters, I'm nervous about putting an outlet below an intake. Hahahah, I came to this forum to discuss exactly this concept! Thank you for getting the ball rolling briancady413 We are planning to build a small office / workshop building. It will be an octagon and hopefully have a small mechanical workshop underneath. The office will be mostly used by my wife, who is a psychologist. She doesn't work every day of the week, and we have been talking about clustering all her appointments together into one week out of the month. That way she can have more free time the rest of the month. The clustering would help with how we heat the office as well. If we do go for an Ondol or Hypocast kind of heating I want it to run solely on prunings from the grapes and olives. Right now a lot of those kinds of branches get burned in this area and I really disagree with that practice. The design should incorporate a means for huge piles of tiny branches to be stuffed inside and lit all at once. Total floor area is gonna be around 20m2. I'm thinking to do a concrete slab for the ceiling of the basement, which is a requirement by law either way. This would allow me the freedom to either make that the bottom or the top of the Ondol. I'm thinking the bottom because I mostly want this floor to heat up quickly when we need it, rather than slowly and retain heat over a long time. But I'm open to suggestions. If we do make it the bottom I could have the slab run at a slant towards a gathering point, so it will be easier to clean with a water hose. I would then build a raised floor on top of that which would be heated up by the smoke passing underneath. What this floor would be built out of is up for discussion still. Could be another concrete slab or it could be other materials. As for the type of RMH to use, I think you are right in thinking about a batchrocket. But I want an even bigger batchbox, maybe a 80 by 80 cm or something. Might have to do an arch for the top. And I wonder if it will scale to that size. peterberg , any input on that? I didn't quite understand your description of the mass you want to use. Here's how I see it: The best use of this tech would be to incorporate a Bell to manage the smoke, similar to what is shown in this youtube video: www.youtube.com/watch?v=tx0BnCsYeXYWas that the kind of design you were thinking about? Forcing the smoke to enter a space where it can hang out until it has given off its heat and cooled down enough to exit through a LOW exit point. Preferably lower than the entrypoint. As an aside, keep in mind that no matter if your floor is going to be set into the ground or raised above the ground, its best to insulate all the way around it using styrofoam or some other non-rotting insulation. At least to 80cm deep if you are doing a 'floor level' floor. I believe this is called 'skirting insulation' but I could be wrong. ------ Here's a mockup of what we're thinking: photos.google.com/album/AF1QipN1rjIlVAiASw2IRbe94_NUWWXmPHHKffkNrPmO/photo/AF1QipOiFJ8vQltNuanANwSXr9to2Bu5X7IiQt9fskBGIt'll have the obligatory reciprocating roof photos.google.com/album/AF1QipN1rjIlVAiASw2IRbe94_NUWWXmPHHKffkNrPmO/photo/AF1QipPiPbB8atwUQ7BEMGGbGdnxrvqAt3QSsI4_loxPAny future pictures of this project will be uploaded here (if its pretty much empty that means the project died with this post ). photos.app.goo.gl/HPn3nVuGVGH7TjNk9
|
|
|
Post by emmaslow on Apr 19, 2020 10:44:57 GMT -8
I appreciate it adds another level of complexity but I think you’d each be better off dumping the heat into water and then running water pipes through your (insulated) slab. I don’t think you’d have enough heat from exhaust alone to create any noticeable temp increase.
I have run water pipes in an insulated earthern slab in the UK, and topped it with terracotta tiles (I needed a very robust top layer), and it works a treat but it does take 2-3 days to warm up. The water runs at about 50c.
|
|