Assuming that one owns a shop vac (which I do) then loose materials could be moved via paper sack.
I'm thinking that this would be a six inch system.
If one were to take 2 1x4's that are 6 feet long and attach them to 2 1x4's that are 22 inches long, you could make a shallow box that is 72 inches by 23.5 inches and 3.5 inches tall. I choose to call this "a frame".
A stack of five frames is then lined on the inside sides with brick (I have lots). Total height is 17.5 inches. Lay down foil on the bottom and coming up the sides. Put in two inches of perlite on the bottom.
And then the brick is laid in for the burn tunnel, wood feed.
The combustion chamber is six inch duct with ten inch duct and perlite and clay. Just like in the video. This piece will stay contiguous during the move.
The bench will have four pipes in it and filled with sand (maybe a mix of sand and ash). Since there is so MUCH pipe, then the whole bench becomes lighter - so weight issues are mitigated. (and the downside of less weight is less mass - but part of the design is to work in the space of a typical floor in a typical home)
The area around the combustion chamber and 30 gallon barrel and the like would be filled in with perlite and wood ash.
The transition from the barrel to the duct will be a little tricky. So far I am imagining that it will be framed in brick to make a 12 inch deep chamber with two bricks over the top and lots of sand/ash over the whole mess. Cleanout would involve setting the sand ash from the top aside (maybe with the help of the shop vac) and pulling the top bricks to get access to this chamber. The beginning of the duct would rest just inside the chamber.
The top of the bench would be 2x4's with a quarter inch gap between each stick. And 2 1x4 sticks that would hold them all together and keep them in place just within the top of the bench. The gaps would allow the heat to pass through.
I suppose one could add a flexible dryer duct to carry the exhaust away.
It could be built in a garage or on a deck. Or patio. It just needs to stay dry. And then the dryer duct could be laid anywhere away from the group.
And, it could be put inside and the duct run out a hole in the wall, or through a window. And since this is portable - it becomes a sort of hand made appliance - I'm not sure what the laws are for that sort of thing. Probably a little beyond burning 50 candles at the same time - or running a dozen propane torches, or having a party with smokers - only the exhaust is routed outside.
In transport, there would be a barrel, lots of bricks, the combustion chamber, lots of duct, wood frames, the wood bench top, foil and paper sacks full of perlite, sand, ash, or a mix of two or more of these.
After it has all been built one time, maybe setting it up would take .... 90 minutes? And taking it all apart would take ... 60 minutes?
So ..... as with many of my crazy ideas, I later learn why the idea is lame - what have I overlooked?
1. dont use the dryer flexihose it slows the exhaust down to much.
2. aluminum tape is your friend tape the joints and make sure they are sealed.
3. i think you will need to morter your bricks and plaster the out side of the burn tunnel.
4. test it outside first
2 and 3) I'm kinda shooting for something that will be easy to take apart and put back together. I think tape, mortar and plaster might be contrary to this goal.
I guess I could try to tape all of the pipes together and keep them as one big gob. They would then just be rather light and bulky.
I was hoping that dry stacking the bricks, combined with a lot of ash would do the trick. I guess I was leaning heavy on the ash plugging any gaps anywhere. If ash won't work, might there be something else that would work? I could attempt to wrap things in foil. Foil is cheap and I can re-use a fair bit of it.
4) How about a garage with the door open? That way my work space is nice and dry.
paul wheaton wrote:
My attempts at drawing this.
The first is without the loose fill, the siding, the bricks in the thermal mass or the top. The second is the same but with the siding.
Looks nice - both safer and more efficient than the open-air radiator, to my eye.
According to one conversation I had with the inspectors, the code definition of "appliance" is "anything used for heating or cooking" regardless of whether it's site-built or portable.
I suppose it could be called a "physics of combustion demonstration device."
Do be sure to give any thru-wall connections proper clearances or insulation. The smaller thermal mass and shorter heat-exchange will mean the exhaust is hotter. Probably not as hot as woodstove exhaust, but I'd aim for that level of protection for combustible walls.
And I suspect you only need the siding around the heat-exchange bench; you might even be able to get away with a washtub sitting on an insulated "sandbox."
I think the wood all of the way around not only lends stability to the outer layer of bricks, but I think it also is an opportunity for a look that some might find more appealing. At least, I think it might open options.
After all - has anyone tried doing a thermal mass in a wooden box before?
buckets with lids and handles (for hauling sand, ash, clay, etc.). I
have four, but could use about six more.
6" duct: at least 30 feet. Plus eight elbows.
10" or 12" duct: three feet.
newspaper: about three inches thick of stacked newspaper
120 lb grease can (I'll try getting this from the local jiffy lube)
red bricks: about a hundred. I might be able to get 50.
wood ash: about four buckets worth - this is something that cannot
really be bought, but should be able to be found somewhere
clay: one bucket. It would be cool if we got it from a field or
something. It doesn't even have to be pure, geologically accurate
clay. It just needs to be clay-ish.
sand: once we have the buckets, getting the sand should be easy.
perlite or vermiculite: they used to sell this by the huge sack that
was, I think, three cubic feet. Three cubic feet would be good, but
.... where is a good source to get a lot of it really cheap?
1x4 or 2x4. 12 eight foot sticks. Or 2x4 or 2x6 would work too.
fuel wood: dry branches or regular dry firewood. I'll need a
barrel load so that I can burn the paint off the barrel. And then
another half barrel load so that we can test the RMH.
Did I leave anything out?
I think it might be too much pipe with too many turns.
I bypassed most of the pipe and it worked much better, but the combustion didn't seem as rockety as I remember. And the exhaust seemed rather smoky.
either way, I'm glad you gave it a shot.
Afterward I felt mighty sore all over. It wasn't until the next day I knew why: I was getting sick. I'm still sick .... but how stressing can it be to take a pic? I'll try.
I have one idea of what might be causing it. .... maybe I'll draw a picture ....
I think the burn tunnel is 7.1 inches high and 4.1 inches wide.
The intersection between the two is .... less. Maybe 20% less. I suppose that could be problematic, but I didn't think it would be this problematic.
Other considerations if the system was build to the drawings is the inside loop; the Apex is a hot gas trap. unless you get the rest of the system working nominally you cant push through the block. with no mass on the system the surface cooling is sufficient to lower temps and give you lots of help but as soon as you get mass around it the temp wont drop fast enough to allow for the system to run correctly.
all this is hemming and hawing from the system i have in my head so just take it for what its worth. other thoughts are that the sand while damp is a good thermal mass but when it is powder dry its a good insulation might cause problems down the road. Keep at it Ah ha moments dont come with perfectly functioning systems they only happen in ones that dont work right.
Of course, the problem with a wider rectangle is to have the brick that spans the burn tunnel.
If I fix the burn tunnel to combustion chamber point, will the four ducts in the bench be okay, or should I drop that to two?
some orientation of bricks will do at least this.
paul wheaton wrote:
So ..... maybe I can just whittle the existing bricks a wee bit to allow the transition from ractangular-town to tubular-town ....
would arranging the bricks underneath the combustion chamber in a more circular pattern to match the shape of the combustion chamber work?
that's roughly what I was trying to suggest.
I guess I'm trying to wave it in ernie's face to see if he'll say "that's stupid because ....." or "yeah, that's what I would do."
as per usual i am going to say..............spoilerspace................... try it and see
Mom's here and we spent the last couple days unpacking her moving van so i have been a little absent.
I think this part is only a little bit of the problem.
I think this part is only a little bit of the problem.
What is the rest of the problem?
but working out one part at a time is the way to make a system work.
I would love for this one to work so i am thinking it through step by step. I dont want to change to many variables at once.
Getting into CAD to work on gas flow is way beyond my pay grade, but you might be able to find someone who could help you with it since you live in a college town. The easy bet is to reduce the bends in the bench.
not generally something i suggest even at the best of times. I would not do it unless i had a really really good reason for it; introduces to many variables. pulling one run off the ducting would work better and be much simpler to figure out.
I have now fully removed the burn tunnel and am going to rebuild it. The changes will be:
1) The burn tunnel will be square instead of rectangular. According to my calculations it should be 5.317 inches square. So, a hair bigger than 5.25 inches.
2) the tunnel will be widened where the heat riser meets the burn tunnel. Similar to what was drawn earlier.
3) I've already shaved about a quarter of an inch off of the top of the heat riser. The previous gap was a little more than 1.5 inches. It is now a little less than 2 inches.
4) Where the exhaust just inside the barrel merged with the first duct was goofy shaped, it is possible that it may have become too small. It will definitely be larger.
5) I want to speed up the build process. I think I am going to create a cardboard form for the burn tunnel. The idea is that the form will represent the final shape of the burn tunnel plus a layer of bricks at the bottom.
Rather than putting a heat riser on a stack of bricks, what about a heat riser that goes all of the way down. It seems like seals between the riser, bricks and the barrel would be easier. Plus, the insulated portion would be taller (thus, better?).
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