Biopowered - vegetable oil and biodiesel forum
General => Alternative heat and power => Topic started by: photoman290 on February 20, 2014, 09:15:20 PM
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after reading bretts post about rocket stove heaters i have been do a bit of reading. they have come on a lot since the last time i looked at them a few years ago. this design looks really good for the coach or a caravan.
http://www.youtube.com/watch?feature=player_detailpage&list=PL01FFC7A3CB99848B&v=4QbTzU-MG5s
not quite a rocket ass heater but should work really well on old pallets. i can get as many as i want in the summer. if fact the local builders merchants are glad to get rid of them. it looks a bit safer than the spike burner.
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Just about out of internet allowance, so I'll have to take a look tomorrow when I get some more.
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I did not hear any noise from it?
Our rayburn will happily go into 'rocket' mode, under the (in)correct conditions - before hearing that, i did not wholly understand why they were called 'rocket' stoves.
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yes i was puzzled about the name as well. my spike heater also goes into rocket mode very easily as well, complete with roaring flames out of the top.
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That looks like a great wood burner an all, but that is not a rocket stove, it's just a wood burner. He's got the wrong idea.
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it has all the elements of a rocket stove, except maybe the extra air input. but the designs for rocket mass heaters i have looked at dont have an extra air input. they tend to have a vertical feed feedbox and a horizoncal burn tube, which he doesnt have but the basic idea is the same. the insulated riser and the manifold are right. the flue could do with coming out further though. what part do you think is wrong?
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I'm in a bit of a quandary now. He's managed to make it to the plan, but I still think he's cocked it up.
Think of the small wood gas camping stove. The only reason it works is that the initial burn is starved of oxygen, by the top layer of ashes. The wood gas seeps out of the hot charcoal layer underneath, out the holes and up the side, where it is re burned at the top, ignited by the flame on top of the initial burn.
In the rocket stoves, the air is shut down, and carefully managed, to get the initial burn to gassify. If there is too much air flow, it's just conventional combustion. It may get pretty hot, and the draw takes the flame up the chimney, but that isn't the essence of a rocket stove. That's just trying to set the chimney on fire.
The main air needs to be going into the secondary chamber, for sure, to drive the secondary burn, but the initial burn needs to be strangled, to build up a depth of embers. Think of the way they make charcoal, that is what your trying to achieve with the initial burn.
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Blast you Bob, I spent hours on you tube looking at rocket and other stoves last night!
check out user ppotty1 some good experimental burners
http://www.youtube.com/watch?v=vRo6UFAfPIo&list=UUvqnmwAjp2JR9nZ4R-qlUdg&feature=c4-overview
http://www.youtube.com/watch?v=KdDkkKRv4aw
http://www.youtube.com/watch?v=qidct-0z7O4
EDIT:
just found one like the first one I ever made, like this from bricks,
http://www.youtube.com/watch?v=r66jjYdBmg8
my second was cast in a wvo tin from chicken poo and cement using 4 inch fence post to cast the chamber.
we cooked meals for the BBB on it.
http://picasaweb.google.com/floraflossieflo/BBB09?feat=email#5357686910693242242
http://picasaweb.google.com/floraflossieflo/BBB09?feat=email#5357708758488082082
http://picasaweb.google.com/floraflossieflo/BBB09?feat=email#5357681150546193394
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its all bretts fault he started it dad. hours? i have spent days... and nights, and brought the book as well. the book is a revalation. well worth the 14 quid or so. google "donkey rocket stoves" for a link to the forum. you can buy the book there. ppotty1 vids are excellent. now if i had a workshop and better access to scrap metal i would do some of his experiments. a yurt in a muddy field is not a workshop unfortunatley. i used to be able to go down to the dry dock and rummage though thier skips, in the good old days. cant do that anymore . elf an' safety. worried i might cut myself and then sue them or something.
GM i think there is a bit of confusion between a rocket stove and a gasifier.
the rocket mass heater, which is what that stove is really without the thermal store, works by getting the riser tube really hot, i mean really hot, up to 1200 C on a good design. this burns up all the oxygen and most of the CO as well. the result is the same as a gasifier, total combustion.
because it is so hot the exhaust can be 30/ 40 foot long with a suitable size exhaust 200mm is a good size. because the riser tube is so hot the draw is enough to put the hot air though 40 foot of tubing. by the time is exits the tubing it is down to 30 to 40 C. al the heat is absorbed in the thermal mass. yes i am going to make one..... just as soon as it stop s raining, and i finish the procesor, and the yurt an the coach and and and.......... check the link for lots of info.
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GM i think there is a bit of confusion between a rocket stove and a gasifier.
the rocket mass heater, which is what that stove is really without the thermal store, works by getting the riser tube really hot, i mean really hot, up to 1200 C on a good design. this burns up all the oxygen and most of the CO as well. the result is the same as a gasifier, total combustion.
because it is so hot the exhaust can be 30/ 40 foot long with a suitable size exhaust 200mm is a good size. because the riser tube is so hot the draw is enough to put the hot air though 40 foot of tubing. by the time is exits the tubing it is down to 30 to 40 C. al the heat is absorbed in the thermal mass. yes i am going to make one..... just as soon as it stop s raining, and i finish the procesor, and the yurt an the coach and and and.......... check the link for lots of info.
It's looking that way. It's me with my wires crossed, not him.
One of my great virtues is I never let go of the stick, even when I know I've got the wrong end of it......:)
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I should have said hours spent on you tube looking at burners yet again, whether it's turks, rockets, rocket mass, masonary whatever, ha ha love em all, and built a few small versions meself, never got to rocket mass version just plain ol rocket, weird coincidence today, the bits of wooden fence posts I used to cast me chicken poo cement rocket stove appeared under a sheet of metal I moved looking for something else.
But I'm thinking now along the lines of ppotty1's woodburner style with glass front door, just coz I like lookin at the fire burnin, mesmerising, I've daydreamed many a cold spell away looking in the flames, but I wanna maybe incorporate the design for running on wvo/glyc/wmo/sawdust too, whatever is available besides wood.
like this one
http://www.youtube.com/watch?v=FLcIrrHjdUM
there is a pretty good book here too
http://lockiemartin.wikispaces.com/file/view/Rocket%20Mass%20Heaters.pdf
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Oh yeah, you probably know anyway but worth mentioning for anyone else reading, but the temps these things can get too you need stainless steel preferably, or very thick steel well insulated, thin steel will just get destroyed.
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ernie and erica wisner seem to be the experts, having built 700 rocket mass heaters i would think they know what they are doing by now. their idea is to make the riser tube out of cardboard surrounded by refractory material as whatever you use will melt eventually. standard solid red bricks seem to be the simplest solution.
i know what you mean about stoves. sitting in front of my spike WMO burner at the moment. can see the flames and hear it as well. cant really get much simpler than a cast iron saucepan with a bit of cast flue pipe welded on the top of the lid with a few holes and a bit of flexy pipe stuck in the top. i am running on red at the moment as it seems to work better than heating oil. less energy but more controllable . as i have to do a 10 mile round trip to get kero it is about the same price as the red comes from just up the road. what i love about it is how fast it heats up in the morning. bit like the old salamanders, but a little bit safer. at least it has flue anyway can get the whole thing glowing cherry red in about 10 minutes if i turn the neddle valve right open.
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Oh yeah, you probably know anyway but worth mentioning for anyone else reading, but the temps these things can get too you need stainless steel preferably, or very thick steel well insulated, thin steel will just get destroyed.
Chug,
I was under the impression that stainless was not as good as standard steel in high temperature applications?
I dont know, however, if that is with regard to physical strength (which is not important here) chemical stability?
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dunno the science or theory I'm afraid Julian, thick steel and cast iron is ok, but my experience from turk burners is that stainless was much better than double, even treble thickness steel, maybe I had bad/wrong steel, but it slowly burnt away, and I've heard others say they've had similar experience.
EDIT: I had a look at metal melting temps and steel and stainless steel are quite close, but I've collected some fire bricks from an old storage heater for future playing with fire.
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we had the ashbox from the range made from stainless. the range was designed to burn coal so we removed the grate and put the wood straight on to the ash box. the stainless only lasted one heating season. not a lot better than mild steel. i dont know what grade it was. think i will use ceraboard next time. the walls are made with that and they are fine.
just to derail you some more chug i have found a interesting design for a RMH (rocket mass heater) here you go.
http://donkey32.proboards.com/thread/560/half-barrel-system
cant wait till the field dries out enough to drive onto. have to remove a tree first that's fallen across the path then i can buy some bricks and start experimenting. if i start now i may have something working by the bbb.
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Bob,
I offered to Brett, but it seems he is only at the planning stage, so ill offer it to you too, if youre a bit closer...
I have about 6m of single wall stainless flexi liner here (5" dia) that ive not been weighing in as i figure it must be useful. Its exactly the thing that you would want for a RMH flue.
I also have a load of night storage heater bricks, which would, i think, be ideal for the burn chamber...
Keen?
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hi Julian , the bricks would be very handy. i am planning to use 8" flue so hang onto that. give me ring if you come down here and i meet you in town. i have had loads of old storage heaters in the past but got rid of the bricks.
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I suspect that its likely you will be up this end, before i have call to travel back down to the edge!
But, if it works the other way, ill be sure to bring them.
They seem easy enough to pick up here - i think it may be due to the way the tips are operated here. Metal is free, but hardcore is charged. So there are probably quite a few knocking about (i put a note on freecycle, and was offered them by a number of different people!)
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yeah I like the half barrel one Bob, love the old scythe damper too!
How about a biscuit tin version of this one, a simple campstove, typically I threw out a few biscuit tins from xmas last week and now aint got one to play with.
http://www.youtube.com/watch?v=SWAsGAi08iI
or this one
http://www.youtube.com/watch?v=OmaCPQ1Aq50
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I suspect that its likely you will be up this end, before i have call to travel back down to the edge!
But, if it works the other way, ill be sure to bring them.
They seem easy enough to pick up here - i think it may be due to the way the tips are operated here. Metal is free, but hardcore is charged. So there are probably quite a few knocking about (i put a note on freecycle, and was offered them by a number of different people!)
not planning to go much further that penzance fort a couple of months unless a booking we are waiting to confirm comes though in about 3 weeks. i have put an ad on freegle. all the ones i had went to people wanting to build patios with them.
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I'm happy to act as an intermidiary if Julian wants to bring them to my place and you collect from me Bob?
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hi jules that would be handy,thanks. i want to come over for a pep talk when i get the processor finished anyway. i have all the bits just been just wet and windy to work outside. well in the yurt but that's more or less outside anyway. i had it all set up and the morning i had to go away for 3 weeks the roof blew off just as i was setting off!! everything in there is a bit damp. need a bit of dry weather before i try and sort it out. at least the processor bits are in the coach. i will experiment with red bricks first then try the fire bricks if they fail.
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"breeze" blocks are really nice thermal insulators, and they last a fair while, but not forever - you may like to try them too?