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Post by ahansen on May 19, 2020 8:55:52 GMT -8
I want to share this becouse it really helpt me distriputing the heat over longer time, like u both had a mansery and a fireplace NOT at the same time like a normal rocket. But whit the barrel in a large "closet" you can have the doors open, for my instent like 20 minute and before it become a souna in the room close the doors ad burn 30 or 50 min more to save heat for later.. different thicknes in the cop around smoke channel will make even temperature from then, and if you leave just after burn and come back 4 hours later you can boost the roomtemperature by opening the doors having 5 cm at the side of the barrel an 60 cm above so the barrel can get out if needed and so on top there is an pizza like oven(if big fire version) on top. works fine whitout the barrel overheats witch one might think. the walls of the closet is easy cobet or bricket, last one i made whit round bricking on top like roman and and some chiken wire to hold the cop whitch might crack but it is to make work no problem.. the hard part is the door/doors witch should take more heat than a woolen blanket sadly.. but fire blanket, metal doors or maby metal framet tile doors works a double door is nice so the opening can be made bigger. any idea on this? maybe wood and some kind of fire board .. i would say you could not have a barrel rocket in tiny house whitout this method beware the barrel only radiate out the doors and the closet take(saves) like 40 procent of the heat depending on the air cirkulating with some shimney effect here too to help cool the barrel. probaly not much as free but fine and at the time u close the door the draft should be more than fine
asbjørn
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Post by satamax on May 28, 2020 19:22:02 GMT -8
Well, i think i understand, picture it. Careful with fire risks. No wood in the structure of that room/closet. At all.
For the door, an aluminium and rockwool door would do fine.
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Post by ahansen on May 30, 2020 1:06:34 GMT -8
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Post by satamax on May 30, 2020 7:43:43 GMT -8
I had proposed in the past, to run the exhaust of a J tube in a box full of pebbles. Which after burning, you would close the said exhaust, and run air through the pebbles. To control the room air temp.
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Post by ahansen on May 31, 2020 2:51:55 GMT -8
the thing is when you just start a fire you want a lot of heat right away and then have some kind of off switch when the room is warm while still burning full power for heat save, still cheap efficient and no water pipes but still more room temperature regulation possibilities and more heat saved. only few fire brick and barrel and the doors whith some cost
so closed pipes going through "larger" pebbles in a closed box system were you can open top and botten to get heat from pipes and or saved heat in pebbles, so this way you allways can regulate to, but if you come home after a weekend gone and want fast heat till rome is warm and then only heat the pebbles after comes a problem
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Post by Karl L on May 31, 2020 10:07:11 GMT -8
Hi,
I am in the middle of constructing a 125mm DSR2 heater that tries to meet some of the requirements you have specified. When I have time, I'll post some pictures in a new thread. The problems this heater is trying to address are these: - Heat up a room quickly from cold.
- Store heat in a thermal mass when the room is hot.
- Work with a non-ideal chimney (that probably can't be lined), with an unknown flue gas exit temperature requirement to generate sufficient draught.
- Overcome the risk of cracks in a single skin bell.
- Flexible/adjustable/experimental design to deal with the many unknowns.
My design uses a welded sheet steel bell, surrounded on 3 sides with bricks (thermal mass) and open at the front (radiant heat).
The amount of heat extracted by the bell (and so the flue gas exit temperature) can be varied by adjusting the air gap between the bricks and the steel bell, and also by adjusting the area of the radiant surface.
These are both 'build options' - but it should not take very long to do the rebuild because the bricks are dry stacked around the steel bell.
It may also work to close a 'door' over the radiant surface, to reduce the heat into an already-warm room. This might push some of that heat in the the thermal mass instead. This has to be tested.
Karl
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Post by ahansen on Jun 1, 2020 5:35:17 GMT -8
Very interesting the door works great! with the doors open you have a lot of heat in front of the oven right away but in the other end of the room its a bit slower heatet becouse the walls around the barrel will take some of the heat but then the walls will take all heat when doors are closet so no need to open window. if you want the far end of the room to heat as fast as with free barrel the burning champer and channels scould be scaled up a bit maybe 40 procent. allso the doors should be as big as posible. at the time you close the doors you would expect less draft becouse of less cooling effect from barrel but at that time draft seems to have build up elswere in shimney and so
its nice to make it so you can reach everywere around the botten of the barrel to seal it or pick things up, so maybe more than 5 cm
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Post by Karl L on Jun 1, 2020 8:24:42 GMT -8
Thanks, that's good to hear about the doors.
I would expect more draught when the doors are closed, because the gas temperature in the chimney would increase, because less heat is being extracted from the barrel.
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Post by ahansen on Jun 1, 2020 12:30:12 GMT -8
aha but less push if no chimney and at that time burnig champers are warm and air flow can be turn a bit down burning a big log slowly, fore cooler exhoust and nice with shoe box to keep track of the burn quality, i'm curious clean second window stays
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Post by peterberg on Jun 1, 2020 22:39:37 GMT -8
Word of warning: a rocket heater, being J-tube or batchbox, won't run properly without any chimney at all. And yes, it has been done, in very specific circumstances such as wind from one direction during all of winter, no openings higher than the heater outlet and a completely sealed roof.
As for the double shoebox, this one in particular won't even start without the draw of a chimney stack. The whole of batchrocket technology leans on amplifying draft by the port's venturi properties. No draft to begin with, nothing to amplify.
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Post by ahansen on Jun 2, 2020 3:26:10 GMT -8
it seems the barrel is cooled quite well even whit walls around maybe the chimney effekt between barrel and wall makes some cooling wind currents atleast when doors on Closet are open well it makes a different when/if the heat reaches the chimney. i made one with to large channels and the chimney newer really pulled, but then it has a good heat riser that had constant push but these air venturi properties is a bit confusing, what matters the most is air different from water... www.pjmotorsports.com/velocity-stacks.htmltechblog.ctgclean.com/wp-content/uploads/Flow-Restriction.jpg
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Post by peterberg on Jun 2, 2020 6:58:25 GMT -8
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Post by ahansen on Jun 2, 2020 10:42:24 GMT -8
so in other words good venturi properties is smokechannels that break air flow as little as posible so air move fast up heatriser into bigger space moving slowly down cooling helping draft. from bottom through smooth port/narrowing a litte into a bigger size bench channel www.pjmotorsports.com/images/bv_img373.jpgchannels not changing size going in straight line to chimney witch narrows like on nuclear plant on way up, ofcouse making sure a enought heat reach the chimney would be the most structural optimal as i see amplifying i dont get.. i think it makes a different when the chimney pulls more than the heatriser push and where in channels this place is changes . so making it so the heatriser push has no problem reathing the chimney to serve the start of the firering so maybe not narrow the chimney since cold air dont speed up but if one start the fire from top slowly in shoebox will the chimney not catch up
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Post by peterberg on Jun 2, 2020 12:17:36 GMT -8
Ahansen, I get the feeling you don't know what the port and it's functions are in a batchrocket system. To sum up: it's a high and narrow opening between the firebox and the riser. Since it's a temporary restriction air velocity will go up and air pressure will go down in that restriction. To put it simple, velocity plus pressure is one number, when one of the two is increasing the other need to decrease.
The result is a pressure difference between the front and the rear of the firebox. This pressure difference is greater than the chimney pull itself, as such the venturi effect is amplifying the chimney pull. No pull, nothing to amplify, yes? The so-called "push" of the riser is only there once it is hot, it's absent when cold.
By the way: another effect of that port is a lot of turbulence behind it in the riser, needed for mixing of burnable wood gas and fresh (preferably preheated) air. Rounding off the edges of the port has the effect of a smoother air flow and inadequate mixing so I recommend against it. Been there, done that, tried and tested, measured and rejected.
In case you like other theories and want to do it your way, please go ahead and build one. I prefer to lean back and wait for the results.
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Post by ahansen on Jun 2, 2020 13:55:09 GMT -8
well some of my mistakes so far has been cooling the air to much before chimney and had to open The port sacrifising the mixing of gasses running only on push making main door smaler.. but it works the heatriser is bigger (ceramic fiber..) and somehow satisfying seeing how the smoke rather want to exit the cleanout on my outside chimney but..
now i see you can waste some heat fore extra chimney draft. but coming home to my new batchbox rocket when its all cold i feel the heatrise is "first" to give the draft especially becouse i had to place chimney outside witch ill newer do again, but warm it gets.. just not right away in that way it goes from push to pull
if the port should work as good as posible it better be the only narrow spot. no need for mixing later.. running through a bench takes quite some draft
shoebox dont need sekondary air since you can keep eye on flame regulating "primary air" enough no?
anyway if you have to convince peoble that want fast heat, cheap build and long heat storing plus not over heating room. it either need more window or open door fire giving heat in front of oven or whit barrel in Closet with doors giving some more regulating options and somtime you dont want to heat up all the mass sometime you want, but the barrel is a luxery item
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