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Changing from propane to 96% efficient wood  RSS feed

 
Mary James
Posts: 145
Location: NW MT Zones 4/5 Rollins Mt
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A Russian Furnace with five horizontal flues was built, tested with State equipment, showing 2000 degree in the firebox and 85 degree at the top of the chimney.  Burns like a rocket heater with initial smoke.  Hence, 95.75% efficiency.

So, if this same principle was inserted into a large water tank, the water acting as the heat sink, the tank lower than the floor of a house/shop/greenhouse/etc., the heated water rising without being pumped, the fuel source being mostly fully consumed in the change, would there be other thoughts out in web world?
 
Walter Jeffries
Posts: 1095
Location: Mountains of Vermont, USDA Zone 3
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We did something like this by simply convoluting the metal stove pipe and having lots of it inside. We burn our tiny $129 box wood stove at full bore most of the time. That heats up the masonry surround we put around it. The exiting flue gases are just barely warm. You can put your hand on the chimney where it exits. Yet we don't get creosote buildup because 1) we burn dry hard wood maple and 2) the long flue is giving time for combustion of the gases. There are improvements I want to do but we're only going through 3/4 cord of wood a year to heat our house so it isn't a high priority on my to-do list.

The key things are:
1) hot burns
2) long interior stove pipe
3) sufficient stove pipe height to get draw
4) masonry around stove and masonry house to soak up the heat

It isn't a "rocket stove" design but the functionality is the same and it certainly sounds like a rocket when we achieve lift off. We joke about using it to get into space. See:

http://flashweb.com/blog/2009/04/pig-farmers-in-space.html



There are lots of solutions that work.
 
Mary James
Posts: 145
Location: NW MT Zones 4/5 Rollins Mt
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The home was built with a hydronic in floor system with a propane boiler as the heat source for both domestic water and in floor heat.  I will be constructing an outside Water HASHSA fueled by wood/etc., which basically incinerates the fuel.  Firing once a week is anticipated except during winter months, yet to be determined, unless anyone has experience with a similar product.    I will also have hot water solar collector integrated into the system which will possibly eliminate firing during sunny days. 

The home is 2400 sq ft, single level with earth shelter on two sides.  75% is 12' ceilings, 25% 9', low E glazing on the east exposure only, extensive and semi intensive green roof system, plenty of stone interior for mass,  ICF for the two berm walls, frame with masonry the others, commercial insulated roof system.

Is there anyone out there  who has any thoughts/experience with this kind of, or, similar system?

Thanks,

M&J
 
Geoff Kegs
Posts: 30
Location: Northern lower Michigan
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Happy house - do you have a link to this Russian wood stove?
 
Mary James
Posts: 145
Location: NW MT Zones 4/5 Rollins Mt
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Hmm a Russian furnace,, I have built somewhere around 18,, did some experimenting on my own and checking out what worked best and so on,,
Albi Barden is a great place to start,, I attended one of his workshops in Montana  years ago,, one of the things I noticed in some drawings is the chimney is part of or is supported by the heater.  I found that it is best to have them separate due to the expansion of the heater itself.  I would be glad to share my experiences with  you if you wish.  Google has tons of hits for Russian Wood heater, furnace, masonry heater, Finish heater and on and on.  I found a good balance with materials in regards to mass and a good expansion joint in the heater will prevent any major expansion cracks.  Kept the customers happy.
The first one I built back in the early 80s was for the local county extension agent.  He kept track of temperatures inside and out at the top of the chimney for a year and came up with a 96% efficiency.  I built a small 3 flu in my home and tested it.  Efficiency was near 80%.  Anyway,, let me know if I can be of help.

M&J
 
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