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Post by northriver on Dec 21, 2010 15:31:32 GMT -8
Right .... something not to do!
I had been using the top of the heat exchanger barrel to melt snow off of some of my firewood. It works really well ... actually too well. I charred some of the wood ... nothing caught fire but probably not far off.
Regardless, I took the wood off, but I did not clean off the bark and small bits of wood. We've had a slight acrid, burnt smell in the house for about a day. Its gone now but so are all the little bits of wood, there is just a fine, ash powder left on the barrel. Pretty hot on top of the barrel!
I have noticed that the top of the barrel pops as the stove heats and cools. Also, when I boiled a kettle of water it took longer than I expected because the top of the barrel was 'popped' out. The kettle did not have a flat surface to sit level on, and consequently heat conduction is reduced.
Somebody (Donkey, I think) mentioned having a thick cast iron stove top with removable plates as the top of his stove. I can see the attraction.
We cobbed over the heat exchange pipes this morning and lit the stove. Lots of steam coming off the bench.
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Post by Donkey on Dec 22, 2010 8:53:29 GMT -8
Drying wood on top of the barrel! Don't do that! I know of TWO house fires started that way. People seem to just forget that the thing IS a woodstove, and there's a HOT fire right inside...  Nice job on the stove.. You got a pop top! Hey, since you're running through wet cob, you may be having condensation in your pipes, at least till the bench is dry. Would you mind sticking a Ph strip (or something similar) in your condensate?? |
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Post by northriver on Dec 22, 2010 12:06:30 GMT -8
Happy to put a Ph strip in.
May have to wait until after Christmas until we are back in Kamloops (our local city) though. I'll see if I can get them in town.
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Post by northriver on Dec 30, 2010 14:40:25 GMT -8
Just before Christmas we finished the heat storage bench of our stove (although it still needs a finish layer, and more cob over the pipes). At some point in the whole process I started to wonder just how much cob was in it (beyond a lot), and how much the heater weighs.
The tractor that we use to move dirt around has a one yard bucket. This means that when the bucket is full it contains one cubic yard of material. We've built a screen that we put over the tractor bucket that allows us to screen material down to less than 1/2" aggregate. We shovel material through the screen and shake the larger material off. What we are left with in the bucket is clay or sand that is ready-to-use for cob.
For the bench we have used two buckets of sand and two buckets of clay (our clay is actually dirt with about 20% clay by volume), or 4 cubic yards of material in total. I am going to assume that one cubic foot of material weighs about 75 pounds. This means that a cubic yard of material weighs 2025 lbs, and there is over 8000 lbs of material in our heater. This number does not include all of the rock we put in the bench or the bricks that form the core of the stove.
Given all of this and the fact that there is still more cob to go onto the bench, a safe estimate of the weight of our heater is over 10,000 lbs. This seems like a good start for heat storage! Our hope is that the wall that the stove is built next to will also store heat from the stove. The wall itself easily approaches 30,000 lbs of compacted dirt, and should store a lot of the heat from the stove as it is gradually warmed up.
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Post by northriver on Feb 7, 2011 21:32:27 GMT -8
Have been occupied with other things for the last month, but have started work again on the house ...
For the last two days I have lit the rocket mass heater ... we are using the bench to dry out washed wool (it works very well)!
I have noticed that if I light the stove and feed long material into the feed barrel right after getting the draft established the flames creep up the long material and the stove back drafts. Long material would be longer than 1' but less than 2'. The stove does not seem to back draft if I wait to add long material until after coals are established. Next time I light the stove I am going to stick to short fuel initially to see if I am right about this. Is this just me or is this common?
I have outside air supply ducting and I wonder if an in-line fan in this ducting turned on during the first 15-30 minutes of lighting the stove would not force 'correct' air flow on start up.
I had mentioned before that the flue exhaust was quite smokey. It is much cleaner now, so I assume it was moisture.
I still have not tracked down a pH strip to put in the flue!
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Post by careinke on Feb 8, 2011 13:55:56 GMT -8
I assume your bench is waterproof since you are drying out washed wool. Could you please tell me what you used to seal the bench?
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Post by northriver on Feb 8, 2011 20:46:35 GMT -8
I assume your bench is waterproof since you are drying out washed wool. Could you please tell me what you used to seal the bench? No, it isn't! We won't be finishing the stove until our house walls are ready to finish too (hopefully sometime this year). The wool is damp from washing, but does not seem to have much impact on the cob it is placed on. The cob gets slightly damp but dries out fairly quickly after the stove is lit. |
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