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Post by permaculturebob on Nov 26, 2019 20:06:52 GMT -8
That sounds about right. I figured I might need blenders- or something to reduce particle size, but maybe there is some sort of grinder that might do even better. I'm thinking about an old masticating wheat grass juicer that I never actually used for wheat grass--it had a cheap chrome plating that started coming off right away so I never got to use it with food, but it might be just right for the pdz
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Post by permaculturebob on Nov 25, 2019 17:44:30 GMT -8
Yes, I've read many of cr's threads and have learned quite a lot reading them. I didn't want to start asking direct questions until I had some experience and knew more what to actually ask experience. That's why the thread has such a general intro. The fact that you had problems dissolving the pdz is interesting to me. what did you diagnose as the issue?
My PDZ is in a sealed plastic bag so I haven't even handled the stuff yet.
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Post by permaculturebob on Nov 21, 2019 13:30:14 GMT -8
It would be wonderful if there was a video with off the shelf ingredients, showing step by step with explicit instructions not complicated with theory or other possibilities. Inevitably looking at the discussions, there are talks of different chemistry possibilities, seemingly trying to bring us up to a level of understanding of how the process works, but mostly just confusing the heck out of me as I impatiently try and get my hands into the geopolymer fun. But after much reading and many distractions I'm about ready to try my first experiment. I can easily boil water, but long oven curing isn't going to happen, so I think a simple 1 to 4 ratio--NaOH -pdz, mixed dry, then a small amount of boiling water (as small as can completely dissolve the dry ingredients), then wait a short time for the reaction to create the binder, then add more water to get the mix to flow into the aggregate, which in my case is Virginia clay ,unrefined, but a high percentage of clay, sifted through a screen. Last year when I first read about this, sweet pdz and NaOH seemed the simple way to go, simple, reliable, but the more I read it just seems to open up all sorts of questions,
I'm reading now about this drive to use acid washes and other processes, and wonder why the simple, seemingly easy pdz process isn't used more
does the pdz geopolymer provide refractory quality strength with high insulation- ie: the ceramic fiber board/firebrick hybrid equivalent? or do I need to expect that this polymer will just be an experiment not truly useful in a DSR core, but maybe a nice way to build a wall? Anyone have any direct suggestions as to what might be a flaw in my plan or a way to make it more fool proof?
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Post by permaculturebob on Jan 14, 2019 16:03:22 GMT -8
Just thought I would post a simple experiment I did with my dsr with glass cooktop, just laying a partial CF blanket on top over the port, and it increased the temperature by two hundred degrees on top of the glass, pushing more heat farther along under the top, including the water tank bell at the far end before the stack. I knew that would raise the temperature, but the difference was more than I expected, especially with such a short test. Likely with a longer test and a full blanket the difference would go even higher. I got the circulation pump hooked into the plumbing,and initial tests circulating water to the radiant floor were promising, but I'll need to wait for tomorrow to do some better testing. The next questions to be answered are about the heat exchange to the water tank, and how much extra heat to send to the water tank bell before it starts wasting heat up the stack. I also need to find a place to install the thermostat sensor to turn the circulating pump off and on
And today I finally broke down and ordered some neoceram for viewing windows, and will take better pics of the fire after I get it installed. I paid 105$ for two pieces 3/16" x 10"x10" and wondered if that was a good price or not.
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Post by permaculturebob on Dec 26, 2018 6:39:07 GMT -8
The double shoe box is elevated off the floor about 18 inches, and instead of an exhaust on top- in front, it is channeled horizontally under a glass stove top from left to right. I'm not quite sure who it was here that suggested having the water tank inside the bell, but it was that idea that led me to my design, which in appearance is like a glass stove top, with an extended simple porcelain covered metal counter top. This extended bell houses a naked 20 gallon water tank with two fittings, one for cold water at the bottom and one for hot at the top. The top fitting connects directly into the hot water feed for my house system, and while in operation the hot water valve to the shower head in my tub is left open, and the cold water flow to the tank is shut off. This allows excess pressure to escape safely, and notifies me when the water is hot as steam starts to escape. Note that this is primarily proof of concept, and not yet ready for prime time water heating, it could easily have safety features added that would further ensure a more automatic type system. Last night I was burning the third batch of wood in the firebox, low grade poplar and some mystery wood, likely not completely dry, when I started to hear the steam. That produced a luxurious long (10 min at 4-5 gal/min), very hot shower (mixing lots of cold water). I was concerned about stratification, and the possibility that all the water would not heat evenly, but the length and relatively constant heat of the shower indicated this was not an issue. The design inside takes the combustion gases exiting under the stove top into a very broad vertical opening that directs the hot gases forward into a circular motion around the whole vertical surface of the tank, with some small horizontal space over and under the tank. These gasses that are further cooled start to sink to the bottom as they circulate. The "stack" entrance is below the bottom of the tank in back of the system, so the exhaust comes in contact with about 270 degrees of the surface of the tank, with some minor contact top and bottom. Note that this stack is actually a powered exhaust by a very cheap, low wattage (about 10)fan. This provides a more or less guaranteed exhaust even at startup, and the exhaust is so cool (around 100F) that more robust (and expensive) equipment is not needed.
The test run last night reached temperatures on top of the port between 900 and 1000 F during the third batch of wood, with a very robust secondary burn at the port. Without testing equipment I have no way of knowing just how clean this is burning, but it appears that the system gets more efficient into the second and third batch of wood by the size of the secondary burn. Perhaps using insulated Fire brick at the port would get the port to temperature quicker (it is currently standard , full fire brick), and adding ceramic fiber blanket over the stove top might also enhance the temperature build up by reducing convection and radiation losses there.
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Post by permaculturebob on Dec 20, 2018 16:04:48 GMT -8
The tank has plumbing connections, but I need a few 3/4 pex rings to make all the connections needed to hook into the main plumbing system. I've done a couple burns without water in the tank yet, but the new wet clay is still takingmost of the heat in drying out so temps are way low through the back half of the bell.
www.permaculturebob.org/2018/12/20/more-dsr-pics-double-shoe-box-rocket/This has some pics of my exhaust in case earlier words didn't describe it well, forgive the mess, it's what all us creative types need to thrive--would you believe lazy? For fun I got a temp reading during the first burn on the exhaust, and temps were around 50-60 degrees F while it was in the 40s outside I expect temps will stay in that range or below 100 most of the time.
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Post by permaculturebob on Dec 18, 2018 11:56:23 GMT -8
I used those dimensions to rebuild my RMH last year, what I have now is based on the sketchup drawing he did for the dsr.
I believe Peter said he would have dimensions for the dsr 2 sometime around the new year.
I'm not in a big hurry to rebuild, just trying to get everything back together; close tolerances, improvised materials and shaky connections make for a fun time
I'll check out the condensing flue, thanks
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Post by permaculturebob on Dec 17, 2018 19:24:09 GMT -8
I think the main reason is that bb rockets come closest to a traditional wood stove, but with better efficiency and greater versatility. I lived for a few seasons feeding a rocket mass heater, it gets real old splitting wood down to be thin enough to work in the j tube, feeding it every 15 minutes (or less), somewhat limited by the amount of fuel the thing will hold. Get the fire started, load it full, then walk away only to remember 30 minutes later I forgot to feed the fire The j tube is sort of a firebugs dream in a way, an open flame that doesn't throw smoke into the room (if it is executed well), not even glass between you and the flames, but when you have stuff to do and just want to heat the house it can take a lot more time and energy. A standard j tube is a great thing to get started with, simpler measurements, nearly foolproof if you follow a good plan, cheap materials, a good learning tool, and for some applications that may be all that is needed. Other people will see a glass top cookstove and a regular sealed chamber where the wood is burned and the j tube just doesn't measure up. I wanted to burn larger fuel (up to three inches dia,) and needed to heat a larger space, but I'm looking at the j tube again for some smaller cabins I'm setting up. There's lots of stuff about "traditional" RMHs over at www.permies.com, and here on the pro boards as well I guess, but i didn't find this site until I had already done a couple seasons with a standard j tube, so my interest was moving away from rockets into bbs and I haven't really looked at them as much here.
Maybe some others can give you a different perspective, but that's sort of how I see it.
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Post by permaculturebob on Dec 17, 2018 10:30:10 GMT -8
I do plan to rely on Peter's results as far as clean burning and such, and it seems like all I'm really waiting for is the design parameters since the outer shell of my build can probably stay the same. I'd like to get as close as possible to whatever specs Peter comes up with
I would like a better definition of what the older j tube terms mean when looking at bb and DSR. People use them like everybody knows, but without a labeled diagram I'm just guessing.
What is the tunnel on the dsr for instance? where does the system csa come from? is it the cross section above the port, or just a ratio of the port size. Is the exhaust diameter critical relative to the "CSA", or can it be any size larger. In my system especially, it would seem air volume movement is a critical factor.
I agree with you about the bb design being less able to start the thermal siphon, which is really what this type of exhaust is. Starting it either with a fan or bypass is somewhat essential, although I do plan to start to experiment with turning it off sooner to give the system a slower movement allowing more time for complete combustion and possibly build up higher temps.
I haven't monitored the exhaust temps since the mass dried out, so that will be the next test, and maybe I'll end up with a remote thermometer on the exhaust outside and a rheostat on the fan.
For now the bell around the water tank is removed,( warmer weather), time to hook up the water tank. That will likely remove more heat for the final push up the chimney. Maybe the DSR2 will perform more like a j tube and I can get back to the good old days where I didn't need a fan
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Post by permaculturebob on Dec 16, 2018 18:46:23 GMT -8
I cracked the first soapstone batch box cover I had and finally found a piece of cf board which I used as the top part of the bb roof, and then a 1"cf blanket, with soapstone on top--that one lasted out the season and i'm pretty sure it allowed for increased temps in the bb.
I never knew soapstone was only good to 500f--thanks for the info, although I did figure out that whatever temps I had were way too hot.
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Post by permaculturebob on Dec 16, 2018 14:52:44 GMT -8
I got a couple short videos to load, one of the top and one of the bb door/window. sorry they aren't longer
all the way at the bottom of the page
They are at the beginning/ going into the main burn, the top will get a bit more active, temps were near 900 at this point.
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Post by permaculturebob on Dec 16, 2018 11:33:17 GMT -8
I have been struggling with the idea of a "normal" stack for some time. Permies has lots of that talk going on, and yet Ianto, whence most of this stuff started, had his exhaust a little above ground level through the wall and in the beginning That was a major talking point about how cool the exhaust was. some people ran their exhausts out through a standard dryer vent opening, and the clean cool exhaust was easy to disguise where wood burning was illegal. One of the fundamental differences in efficiency was how a cool exhaust meant more heat stayed in the building. I read one post about how his building site was special, dependable wind velocity and direction,and only a few people could get away with it, otherwise a "normal" draft had to be designed increasing exhaust temps and decreasing efficiency. My own experience tells me that one of the chief problems is simply the exhaust is down where you can smell it--and even if it has little odor, there's still lots of carbon dioxide. My fan is not very powerful, and since it operates at a cooler temp (all the way at the end of the exhaust) it and the pipe don't have to especially robust. In my original barrel bell rockets, just the push of the exhaust falling from the top of the riser was more than enough to create a good draft to push through 16 feet of horizontal bench, 6 -8 feet of vertical, and a few feet horizontal away from the building, although startup could be a little tricky, and when wind direction and velocity was erratic it could create some blow back occasionally. When I started playing with the batchbox design I found the fan was the only way to use my system with almost no smoke at start up. Playing with the dsr it was a godsend to start testing before everything was perfectly air tight. I'll save the rest of this rant possibly for a separate thread (is there an existing one on exhausts?)
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So if we both understand what I was saying, were you saying that your top glass does not soot up directly under a cool pot? I have noticed a lot of temperature increase when I lay a cf blanket on the stove top. I'm not sure if others have played with that idea, but it is a fairly easy way to control where the btus are used. It wouldn't surprise me if my main problem was the wood I'm burning. I'm also looking forward to some dimensions for the dsr2--I just noticed a new thread Peter put up, on converting DSR to DSR2. the sketches so far do not have the firebricks shown, so the cf board bb could be any size, and one post where he talked some about dimensions was incomplete and still in the testing phase, so I'll wait to start rebuilding what I have. It will be enough to install the plumbing for the water tank and get some hot water for right now.
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Post by permaculturebob on Dec 16, 2018 10:16:11 GMT -8
100F/37C is too low exhaust temp for a normally aspirated system, I have no idea what's OK with a fan driven setup. I would really recommend you get a proper insulated chimney. An insulated afterburner will give better secondary combustion for sure. I wouldn't worry about cracking the ceramic cooktop, they designed to cope with cold pans being put on top when it's red hot. They have almost no thermal expansion. videos can be uploaded to a free youtube or vimeo account and then linked to on the forum or on your blog etc. Mine are here: vimeo.com/user44736525800F/900F isn't too bad for the hotplate. I was regularly getting 1000F on the steel hotplate on my outside setup last summer. Something is wrong with the burn if you're getting that much soot though. I get a bit of a tint on the front glass a few minutes after lighting, still clear enough to see through though, and that's gone back to completely clear by 10 minutes, and I get none from the coaling phase. If your wood is not properly seasoned and dry then that will do it, a lot of cold uninsulated mass in the firebox and afterburner will do it until it warms up, otherwise it's too much or too little air. I'll go ahead and move my reply to the DSR topic like you suggested, since it does have more to do with that type of system
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Post by permaculturebob on Dec 15, 2018 19:21:54 GMT -8
I use an old 12v fan mounted in the oversized flue pipe that runs about 8 feet up to ground level, then horizontal out away from the building, then turns and faces down. I have been leaving the fan on for the whole burn, and this is quite an effective substitute for a bypass damper control. Also serves as an aid just keeping air moving across the fuel like a bellows when it is getting started. My exhaust temps were way low measured on the outside pipe, around 100 or so(F)
I don't have an observation window for the top box, so when it is clean the secondary is visible through the glass stove top .
I'd love to be able to post videos, but so far I only have my website and have never explored posting vids, although sounds like a worthwhile learning process. For now I can only say temps on top regularly run mid 800s to mid 900 s(F) and the fire fountain keeps about a foot diameter circle cleaned of soot when it is running, but then leaves a fresh film of soot during the coaling at the end of the burn.
After watching a circle of soot appear on the glass when boiling water in a pot, I started to think about the temperature loss of cooking, then the loss to the air during normal operations, and have started to play with insulating the top with CF to see the effect. So far it does seem to enhance the burn temps in the secondary chamber, and I'm starting to think this may be the answer to getting a fully functional oven (over 400 F) while the burn is going on. It will also push more heat to the water tank in the farthest part of the bell.
Since I'm pretty new at using this glass top, I'm a little concerned about creating temperature differentials and whether it might crack the glass due to uneven expansion.
All the way at the bottom of this page I added recent pics of secondary flame through stove top and flame through the visions lid that is the firebox "door"
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Post by permaculturebob on Dec 15, 2018 16:42:28 GMT -8
I use an old 12v fan mounted in the oversized flue pipe that runs about 8 feet up to ground level, then horizontal out away from the building, then turns and faces down. I have been leaving the fan on for the whole burn, and this is quite an effective substitute for a bypass damper control. Also serves as an aid just keeping air moving across the fuel like a bellows when it is getting started. My exhaust temps were way low measured on the outside pipe, around 100 or so(F) I don't have an observation window for the top box, so the secondary is only visible through the glass stove top . I'd love to be able to post videos, but so far I only have my website and have never explored posting vids, although sounds like a worthwhile learning process. For now I can only say temps on top regularly run mid 800s to mid 900 s(F) and the fire fountain keeps about a foot diameter circle cleaned of soot when it is running, but then leaves a fresh film of soot during the coaling at the end of the burn. After watching a circle of soot appear on the glass when boiling water in a pot, I started to think about the temperature loss of cooking, then the loss of heat to the air during normal operations, and have started to play with insulating the top with CF to see the effect. So far it does seem to enhance the burn temps in the secondary chamber, and I'm starting to think this may be the answer to getting a fully functional oven (over 400 F) while the burn is going on. It will also push more heat to the water tank in the farthest part of the bell. Since I'm pretty new at using this glass top, I'm a little concerned about creating temperature differentials and whether it might crack the glass due to uneven expansion. All the way at the bottom of this page I added recent pics of secondary flame through stove top and flame through the visions lid that is the firebox "door"
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