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Post by Donkey on Apr 24, 2015 21:10:22 GMT -8
One of the issues that we had was that the firewood that was available was very long. When placed in the firebox, one end of each stick of wood would be almost in the port, while the other end occluded the air intake. Several times the stove went into fuel overload with not enough air for combustion. Reaching into the fuel from the primary air intake with long thin sticks and clearing space for more air always seemed to fix it just about immediately. Next time, it would be wise to look at the available fuel source before building the demonstration stove, a slightly longer firebox would have made our lives a LOT easier.
I had a GREAT time! It was very nice to have met with Peter in person after years.. The event was amazing, definitely worth making an annual appearance!
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Post by Donkey on Apr 22, 2015 20:14:45 GMT -8
To answer your riser/barrel gap question: Firstly, there is the L-tube feed, J-tube feed and the Batch-Box; they are all different, have different parameters and probably should not be mixed and matched too much. With the J-tube barrel dimensions, traditionally gaps were given to avoid pinch-points. Heat characteristics, when noted at all were noted in very limited ways; Ianto noticed that his tea water seemed to boil faster with a tight top gap, I noticed that the barrel seemed to give more heat to the room with large top gaps, Peter added bell technology and changed the conversation completely; none of us developed a formula to describe what we experienced. As to the gap difference where it applies to the Batch-box: it is my understanding that the larger gap is a best guess, it's a recommendation to avoid overheating of the barrel-top. Batch-boxes dump far more heat, moment by moment, than the other types of RMH; with such an overload of heat, the barrel top can be in real danger of failure. No formula has been discovered or put forward, all of the information has been empirically derived.
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Post by Donkey on Apr 22, 2015 19:49:08 GMT -8
I think you have identified the problem... so many people want to learn but without a qualified instructor it seems this forum has years of chatting under its belt but keeps going round and round and not solving several of the remaining design issues - I can understand the cost of instrumentation but several forum members/moderators have it and still have not publicly stated results regarding the mentioned issues... and as you say "When nobody answers, you are perhaps asking for calculations which don't exist"... which begs to ask the question "Why has so many people built their stoves/heaters if not to solve the mentioned issues? The least they could do is report back what works for them... Peter, I think you are playing your cards close to your vest since this is as you said "not a consultancy". I see Pinhead? has online related stove/heater simulators - but I am unable to move anything around to change variables - just nice animations - so once again what appears to be an expert is holding his cards close to his vest. Thanks for you help to date... it was educational while it lasted... and since I'm not into commercial stoves/heaters for any hall of fame ribbons... I'll just have to build and optimize with trial and errors... maybe I can report back to those who actually helped... lol @drphol, My understanding is that everything that is now known about these stoves can be found here for free, just your time to look. Chances are, if it's not here, it has not yet been quantified or verified by test. Peterberg and others (myself included) have spent thousands of man-hours of work to discover what is now known on this subject, they (we) have given it all away to the community and held none of it back. While much has been discovered and quantified, there is still much to discover. If there is some area that is still grey and you want more information, if a lack of data is burning a hole through your need to understand, I suggest you lend a shoulder! Can't find an adequate answer to your question? Solve it yourself and give back as others have done before you. Build a test bed, define experiments, do the tests and contribute! Return with results and share, it's what these forums are FOR. If on the other hand, you just want to build a stove that works; rules of thumb will build suitable heaters (which is the goal) without all of the hyper-numerary hair-splitting. One can get on with it using current information (found freely here) and produce one of the finest heaters available.
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Post by Donkey on Apr 22, 2015 19:12:19 GMT -8
Those things rock!
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Post by Donkey on Apr 9, 2015 22:25:42 GMT -8
Wow.. That's a heck of a lot of sawdust! It can be mixed with clay and used as insulation in some of the more neo-lithic (not often long lasting) stove models.. I've seen stoves that are designed to burn specialized biomass pellets, which can be pressed in a home-made gizmo (you can search the forum here for that) . Lots of possibilities!
I suppose it can be used to build hugel beds, don't mix it with the dirt/soil, but make a distinct pile/row out of it and cover. Mixed in, it will sap nitrogen like gangbusters before it's rotted and then gives it back.. If it's a distinct layer, the interface to do the nitrogen transfer thing is more reasonable.. You'll probably want to plant in nitrogen fixers anyway and maybe even salt it with some mushroom spores/mycelium, if it's not already.
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Post by Donkey on Apr 9, 2015 20:57:37 GMT -8
Campaigner (ENFP-A)
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Post by Donkey on Apr 9, 2015 1:08:09 GMT -8
It IS appealing. Cheap and simple too. I think that definitive answers will only come from trying it. It should be pretty easy to test, since you have the radiator already. You don't even need to build a stove to see if the radiator will work, just a pot large enough to accommodate.
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Post by Donkey on Mar 30, 2015 20:26:52 GMT -8
I don't know that anyone has used a car radiator, I've wondered if it would work myself but I've not heard of it being done yet. I called the manufacturer of a different heat exchanger (hot air to water) and after a long conversation, learned that that type of heat exchanger probably won't work. I think the thing to do is estimate how much water to water surface area is present in your exchanger. You want as much as possible. As a comparison, 60 feet of 1/2 inch copper pipe (as a coil) has around 7.8 square feet of surface area. My small experience suggests that twice as much may be about right.
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Post by Donkey on Mar 28, 2015 9:23:30 GMT -8
Since the connecting pipe between the barrel stacks is a new shiny piece, (in the video) you can see the oxidization colors form as it heats up. The pipe itself looks to be in the 400-500 F range..
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Post by Donkey on Mar 28, 2015 9:08:51 GMT -8
Oddly enough Daryl, I have thought about that meet and greet party a few times myself.. Almost did it last year. I wanted to start small so I put feelers out to some key people. Unfortunately, the dates that worked for me were no good for anyone else so it was a no-go. I think that there should be some kind of annual Rocket Stove enthusiast meet.. I would gladly host the first. Any ideas about when, and should I start a new thread??
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Post by Donkey on Mar 28, 2015 9:03:08 GMT -8
A solar hot water loop could be connected to the stove storage mass.. Even just a little pre-warmer can make a BIG difference in fuel savings.
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Post by Donkey on Mar 26, 2015 18:08:00 GMT -8
I've often thought that a metal bodied stove could be built that uses water as a mass. It could be light enough to move when empty and filled with water when the mass is needed. I can imagine a lot of different ways to use the water, with an open system being the safest, low-tech option. I imagine a lightweight refractory/mineral insulated heater core; the water tank could be built as a bell with the water in an outside, double skin. The system could be built in modular sections for maximum versatility..
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Post by Donkey on Mar 24, 2015 19:46:19 GMT -8
Stoker, In your post here you've mainly described a light, portable stove. I'm sure by now you've read about the functional difference between mass and non-mass stoves?
In my experience so far, it's easy and cheap enough to build a mass stove, almost by the book and just leave it behind when you move the tent.. The qualities provided by mass are too good to pass up.
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Post by Donkey on Mar 24, 2015 19:29:13 GMT -8
About the overall design: Sasha's plan is a combination shower/sauna, to be heated from one fire. The system would have a bypass/gate arrangement to guide heat to either a sauna or a double boiler hot water system.
The shower would be used daily or nearly so, the sauna weekly and on occasion, more.
I recommend that the sauna be as insulated as possible, use as little thermal mass as you can in the building and heat exchanger(s). Thermal mass isn't your friend with saunas; for every log you feed in a for the people, you'll feed in one (or more) for the cob! I would not build a bench run, but use a metal bell/barrel instead. You can pour water on the top for steam or use through-pipes and a valve upstream. Think fast, intense heat; even though it will dissipate quickly, you really don't need it after the sweat is done.
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Post by Donkey on Mar 21, 2015 18:50:23 GMT -8
So.. Wolf1004 suggested to me that PEX might be a good choice. I honestly hadn't thought of it, as it's a material that I know so very little about. Wolf said:
I think you would need to make some kind of scaffold or framework to wrap it around, something that can be suspended and keep the PEX from touching the sides. I'm also assuming that the PEX will not be as conductive as copper, so you will need a lot more of the stuff. This should be OK, as long as the price is right.
Any suggestions or ideas about how much would do the job?? Anyone here work with the stuff enough to have an idea?
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