Anyone biuld an Outside Water Boiler Wood Heater?

[AltavistaLawn]

These are the heaters that sit outside your home, up to 100 feet away, burn wood which heats water up to around 200 degrees. The water is then plumbed underground to inside your house to a core which is sandwiched between your original heater and squirrel fan. A separate thermostat controls the heater draft, pump, and fan blower, the original heat becomes your backup.

A buddy of mine built one out of a 275 gal oil tank, he hasn't quite finished it yet; its not plumbed in. But it burns good and heats the water to 160 to 190 deg.

Thanks,
-Billy, out.

 

[toolaholic]

try a search on weld talk forum or shop floor forum

 

[hockeyhead]

Go to this site; http://www.arboristsite.com/

a few guys here have built their own, and quite a few more have bought and installed it themselves, search under firewood and heating with wood forum.

 

[CurlyDave]

These boilers tend to smoke a lot because the firebox is cold.

Be sure to put one far from your house, and be kind to your neighbors also.

 

[jimgerken]

Living in southern Minnesota, I started one with the intention of burning dryed shelled corn in it. I stopped construction before finishing the burner assembly itself. I decided to instead build one that burns cob corn. Cob corn can be simply dried in a crib for a month or two and will then burn well. The cob itself also adds a valuable source of heat. Cob corn is so much cheaper than shelled corn it is rediculous. The cost of drying shelled corn is too high now with high LP gas prices. I figure I could raise about 5 acres of scrubby corn, harvest it on the cob with simple equipment, dry it for 6 weeks in a crib for free, and have a winter's supply of heating fuel. To do this I must overcome one remaining challenge: handling of the cob corn. It is very convenient to auger the shelled corn, metering it into the stove burner automatically bit by bit. But cobs are a challenge to handle. They don't auger unless your auger is about 16 inch diameter. So I am back to the concept phase of the project. I am attaching a photo or two of the original design burner, for shelled corn burning. The parts are jigged together but not welded in these photos. They never did get welded, still laying around the shop in a pile.

 

[AltavistaLawn]

Thanks guys.

 

[DavidVT]

I use an outdoor furnace (Hardy). I got it cheap and being all S.S., I expect to get some life out of it. It has a forced draft and with good wood does not create too much smoke. I live in a rural enviroment.

I have done some reading about the smoke issue and it seems to center around the inability to get the inside of the firebox hot enough. This is due to the fire being cooled by contact with the water 'cooled' walls.

An interesting development that I read about which is being experimented with now is lining the firebox with firebrick or some hi-tech material. This can allow the fire to reach a more efficent temperature.

Surely there are good things about an external wood stove. However, if you are building or buying one of these, do your homework on heating system hook up costs, excavating costs, and wood costs (if you have to buy wood). Also, don't underestimate how much of your time is going to be tied to the feeding of the stove.

 

[JimWalch]

Living in southern Minnesota, I started one with the intention of burning dryed shelled corn in it. I stopped construction before finishing the burner assembly itself. I decided to instead build one that burns cob corn. Cob corn can be simply dried in a crib for a month or two and will then burn well. The cob itself also adds a valuable source of heat. Cob corn is so much cheaper than shelled corn it is rediculous. The cost of drying shelled corn is too high now with high LP gas prices. I figure I could raise about 5 acres of scrubby corn, harvest it on the cob with simple equipment, dry it for 6 weeks in a crib for free, and have a winter's supply of heating fuel. To do this I must overcome one remaining challenge: handling of the cob corn. It is very convenient to auger the shelled corn, metering it into the stove burner automatically bit by bit. But cobs are a challenge to handle. They don't auger unless your auger is about 16 inch diameter. So I am back to the concept phase of the project. I am attaching a photo or two of the original design burner, for shelled corn burning. The parts are jigged together but not welded in these photos. They never did get welded, still laying around the shop in a pile.

Why not just coarse grind the cob with the corn on it after you dry it?Problem solved!

 

[jimgerken]

Grinding the cob. That's worth considering. Dry it on the whole cob, then first thing when removing if from the the drying crib run it thru a grinder and into an auger, then on to the stove. Interesting. Will be thinking it through. Thanks!

 

[BTDT]

Run it through a shredder/chipper.

 

[jimgerken]

I think the right tool is called a Hammer Mill. It contains interchangeable screens to determine the average size of material coming out. It does not need sharpening 'cause the grinding elements are swinging "hammers". It may be similar to a shredder. Thanks for the ideas, I am re-energized on this project now.

 

[cmhyland]

A Hammer Mill is the Shredder side of a Chipper Shredder..... So as others have suggested running it through a Chipper Shredder on the Shredder side would work.

It would seem difficult to get this to burn if its too fine... I suspect you need air space to get this all to burn and not just smolder. So more coarse is better ?

Regards,
Chris

 

[jimgerken]

Yea, I suspect too that coarser is better, but it "must" be augered. I am sure there is an optimum size fuel particle. Dust would be tough to work with since the air wouldnt pass thru it for good combustion. So I would start by using about a 2 inch hole screen installed in the hammer mill, and experiment from there. This is not going to be as easy as the shelled corn burning, I can see that now as you guys are drawing out the details. The variety in fuel particle size will be a variable to contend with. The shelled corn has the luxury of being such a nice consistant particle size, for process control reasons.
BTW, the burner is designed to provide forced combustion air, introduced through holes in the sides and bottom of the burner trough. The burning fuel is also stirred on its way down the length of the trough, finally dumping out the end, hopefully as ash and clinkers. Ash and clinkers fall into a drawer for manual removal, but this too could eventually maybe be augered into a bin or a cart.

 

[SPIKER]

Jim:

I would not auger into the top like suggested or how I perceive you were stating that you would do it. I would auger into the BOTTOM of the burning container/pit/chamber. Put the AIR into the bottom as well pushing the new ready to burn material UP into the HOT coals which are burning then the burning coals will continue to burn and eventually be pushed UP and OUT into a larger catch basin which can then finish burn and the ash would then be taken out form here. all clinkers ash and other non-burnt material would be in the outer ring/pan which could be again augured out or simply shoveled out...


I've seen other designs similar to this and worked great, an OSU green house uses a similar design which has SAND suspended in air (Fluidized bed) and the sand is heated with nat gas, then they auger in ground rubber and more air. they get LOTS of BTU's out of the material this way, the sand traps the burning rubber and temps are above 1400 degrees so 0/no toxic emissions. they then heated water with the hot jet blast If i remember right was a great system as lnog as the fluidized bed stayed fluidized. worked in a kiln/smelting pot type chamber.

mark M