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Post by woodlander on Feb 20, 2011 3:26:59 GMT -8
Donkey, at the end of your long burn tunnel is there a grate for speedier initial combustion? I noticed that an air vent at the point of fuel ignition is a feature of some rocket cookstoves.
My stove (remains of) has a long tunnel at the end of which is an aperture in the vault for the fire to rise and return back towards the room heating the stones (just like a sauna) in the process.
However, my question was provoked by a hole low down at the end of my tunnel and I'm not sure whether this needs to be kept in my restoration project or not. It could well serve as draught because it is positioned below floorboard level of the next room, thus permitting direct draught from outside.
Sorry I can't post any pics right now, but I hope you can follow my description and question.
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Post by Donkey on Feb 20, 2011 17:17:45 GMT -8
I've got no grates anywhere.. It was originally designed with a grate directly below the heat riser, but It never got installed or used that way. Remember, it was supposed to be fed wood through the front door, I just found that it works better through the back door instead.
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bud
New Member
Posts: 11
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Post by bud on Mar 7, 2011 4:21:56 GMT -8
The "if I were to do this again" rag: I'd use a small-ish metal radiator, like half of a barrel or some such. It would be nice to get a faster heat-me-up when the house is cold. |
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Post by Donkey on Mar 10, 2011 15:33:16 GMT -8
I could build a bell, though that's not really my plan right now.. I'll probably place a barrel in the usual place and bury most of it in cob.
Yep, that cylinder is the heat riser. It's castable refractory out of a bag. 8 inch internal diameter, forgot the wall thickness. It's a classic heat riser in the usual position, just covered differently and uses a brick "downer" to move heat down into the bench.
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morpho
Junior Member
Posts: 50 
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Post by morpho on Jun 29, 2011 17:13:09 GMT -8
WOW donkey,
I have not been online for a while and have obviously missed out on some developments.....that is one serious Rocket!
Now I need to rethink what I might do with the new one.
I sat in front of mine for two long cold winters thinking that there must be a way to eliminate the vertical feed tube so you can see the fire.
My wife will be very happy.
10,000 plus views.huh...thats a lot of interest in one mans heating implement!
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Post by Donkey on Jun 30, 2011 21:24:13 GMT -8
10,000 plus views.huh...thats a lot of interest in one mans heating implement! ;D |
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Post by Guarren on Dec 14, 2011 16:29:47 GMT -8
What a great resource, you guys are awesome!
I'm brand new to this concept and loving it. I'm excited to get started with some outdoor test runs.
I'm interested in using the stove mainly for heating.
I'm interested in the idea of the long burn tunnel so that you don't have to fiddle with the fire when you burn it. Donkey, your happy accident with the ash clean out sounds like the answer. I wonder if we could extend the burn tunnel a foot or two so that it's easier to burn for long periods like a wood stove (not that I don't enjoy playing with fire.) I'm worried about the fire creeping back to the opening and not performing like a rocket stove. Here's a few ideas.
a. Maybe having a fresh air feeder that is just inside the burn tunnel, close to the heat riser so that the air isn't drawn from the burn tunnel and won't creep up it. (Or in the bottom of the heat riser.)
b. Making a spring assembly that pushes the wood up against the heat riser so that it is constantly fed as it burns.
c. Making the burn tunnel at a slight downhill slope.
Hopefully this way you can feed the stove once and it will burn for a long time and heat the stored mass hotter for a longer storage time.
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Post by Donkey on Dec 14, 2011 17:03:53 GMT -8
Hmm..
If you do ALL THREE, it might work. If for some reason the wood gets jammed and won't slide forward, it'll smolder, smoke and die out.
Sounds complicated.
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Post by leewaytoo on Jan 13, 2012 11:00:53 GMT -8
hi,
is your "new" feed tube from the back actually ouside? just asking because of the windows to either side...
also...
what materials would be best to use in order to avoid ever having to be replaced?...
cast iron?
have you thought of using a glass door?
what if you had a heated air source that fed the secondary burn that you could use for
quick heat up of your house and then close off for normal burn?
the above would mean that you would have a "blast furnace" at times, so the burn chamber would have to be built using fire bricks?
maybe the whole stove would need to be fire bricks then cob over?
would fire bricks last forever vs metal?
thanks in advance
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Post by Donkey on Jan 13, 2012 17:56:16 GMT -8
hi, is your "new" feed tube from the back actually ouside? just asking because of the windows to either side... No.. It's in the solarium. Depends on too many factors to make a simple, blanket statement. I used the cast iron pot-belly stove top for it's durability as well as it's convenience. Yep, though I decided not to do it. Airflow should pass in and over the glass to keep it cool and prevent breakage. My design didn't allow for that, so... Dunno.. Maybe you could re-state that in a different way, not sure I'm visualizing your intent. Nothing's gonna last forever. I built the internal core of this stove with cob made of fireclay. It's doing great, there is some damage of the regular cob that comes in direct contact with the fireclay. Interestingly, cob that is NOT in contact with a different material is doing fine as well.  |
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Post by leewaytoo on Jan 14, 2012 5:19:28 GMT -8
in another design, there was a tube (copper?) from the outside air into the burn chamber that
ended up supplying heated air just past the burning wood at the opening for the exhaust.
this created a "blast furnace" effect as it turbo charged the burning of the gasses. this is a secondary air supply.
i was just wondering if this would be a way to quickly heat up the space then have a shut
off valve and return to normal heating. the design stated the need to use "fire bricks" due
to the increased temps.
could it be that "distance" "thickness" is a factor in the "cob" and "fireclay" not doing well?
meaning if the fire clay were thicker then less of the "intense" heat would be passed on
to the cob?
not sure if i read that you were from Homer,ak?
i grew up off of kalifornsky rd.
cut cords and cords of wood inorder to buy my first motorcycle.
have fun...
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Deleted
Deleted Member
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Post by Deleted on Jan 14, 2012 7:08:04 GMT -8
Likely a heatpipe. en.wikipedia.org/wiki/Heat_pipeNo simple tube or even a massive copper bar could move enough heat for a significant effect. Creating a water heatpipe is simple. Just close the tube by welding it while a small amount of Water is boiling inside and steam is coming out. A welded water heatpipe can operate above 300°C. The temperature difference from one end to the other will be very small even if it would be several meters long. If the cold end stays around 300°C the hot end can not become much hotter. Even a heatpipe made of stainless steel (can operate at higher pessure/temperature than one made of copper) can move a lot more heat than a massive copper bar. |
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Post by canyon on Jan 14, 2012 11:15:58 GMT -8
i was just wondering if this would be a way to quickly heat up the space then have a shut off valve and return to normal heating. the design stated the need to use "fire bricks" not sure if i read that you were from Homer,ak? i grew up off of kalifornsky rd. cut cords and cords of wood inorder to buy my first motorcycle. have fun... If your needs are to have more of a bump in heat initially than a barrel over the heat riser can provide (perhaps you might clarify your needs better) you can add an isolatable loop right after the barrel (or heat riser if you don't have a barrel) going to a heat exchanger for your needs (hot air it sounds like). You don't want to take any heat from before the top of the heat riser or you will be taking away from the combustion. I am the one from Homer. We did a rocket mass heater workshop in Kasilof (north cohoe loop) in September and I have a friend that wants one this summer on kbeach road.  |
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Post by leewaytoo on Jan 14, 2012 18:45:27 GMT -8
eddiem.com/projects/wood/turbostove/stove.htmlthe above link is a working principle of the idea.. what i am proposing is what i read somewhere on the net. by adding a separate outside air source that is heated and located after the wood being burned, right before the updraft into the barrel. this creates a "blast furnace" effect and greatly increases the burn efficiency. also.. when constructing the heat exchanger inside the "bench", i read that a rectangle would be better than a circle for heat transfer to the cob.. what i would like to try would be to cover the heat exchanger with cob to about two inches then install another exchanger along the top of the path of the first exchanger with ducts & vents that would open to the room through the cob at floor level for incoming air and then ducts that would run up the back inside the cob to vents. the vents would have the ability to be closed off like normal floor vents in a room. just thinking that this might provide more heat quicker. once everything is heated up in the house, then close the vents. thanks again..
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JJ
Junior Member
Posts: 56
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Post by JJ on Jan 23, 2013 16:19:14 GMT -8
Concrete would likely heat-shock badly. My stove has heat-shocked a little up at the top. Nothing leaks out and it isn't really a problem, but it isn't the MOST attractive feature. It's really best to have the thermal mass in the space that you live in. Not practical to put all that weight up on the first floor of your pops place, a lot of shoring up would be needed to hold it. A foot or more of floodwater in the basement... Wow. whatever you make will need to be up on some kind of foundation above flood level. Probably NOT the most pleasant to go downstairs and feed the fire in the flood. As to internal drawings... Lets see what I can do.. Let me think about it. What is the material that you used for your walls and the outside of that stove? Is that loam with silica...or...? |
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