Visit to a Outdoor Wood Boiler

Visit to a Outdoor Wood Boiler

PostBy: Uglysquirrel On: Sat Jul 05, 2008 9:59 pm

I had an opportunity to visit a 2 yr old house with a 124K Central Outdoor Wood Boiler. House is a log cabin, 1400 ft2, R-15/19 walls, R-38 ceiling, low e glass, pretty high tech with plastic radiant piping under the floors, boiler is 70' away from the house . He burnt 12 cords of wood last year in a not so cold winter. Quickly saw why he burnt so much wood. He burns unsplit 6 to 8" logs, most of them are quasi-green. The fire chamber is a large plate steel with water on all sides so the fire box never gets really hot, suggesting a low temp fire and likley a lot of smoke (He noted no neighbors were around). Minimal heat transfer design before the smoke goes out. He has 4 zones plus a master pump, thats 5 circulators running all the time, the heat is always on even on warm winter days (just like my Mark II will be), house cools by the windownator method. A look in the firebox noted 1/8" or more like 1/4" (at the top) of creosote which he was scrubbin off with kerosene. This creosote does not help heat transfer.I wonder if the creosote ignites...

I was left with the thought that unless you burn well seasoned wood, the efficiency of most of outdoor furnaces is like 20-25% which is what I read on http://www.woodheat.com This house, if he had a internal wood stove, would burn maybe ~3-4 cords a year. He loads 3-4' pieces in 2 x a day. He gets the wood free so hey, this is one way to do it. Me, I'll do coal.
Uglysquirrel
 
Stove/Furnace Model: Pocono

Re: Visit to a Outdoor Wood Boiler

PostBy: Freddy On: Sun Jul 06, 2008 4:12 am

A person does whatever he can do. There's one of those in town here & it smokes & stinks like you wouldn't believe. Can't blame they guy for heating cheap, but, ewwww, the smell & the mess.

My name was giving to a fellow that is (was?) just about to buy a newer style outdoor wood boiler. It is a gasifier and does a good clean job of burning, but, dry wood is highly reccomened. He does not have a source for free or cheap wood. We talked for almost an hour and in the end he realized that if he were to burn coal he'd save a pile of money over this wood boiler and also do less work. I wonder if he'll call back and tell me what he decided?
Freddy
 
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined

Re: Visit to a Outdoor Wood Boiler

PostBy: Uglysquirrel On: Sun Jul 06, 2008 5:53 am

Hi Fred and the say hi to the doggie,thanks fur the reply, along that same line, are there any "outdoor" coal boilers ? To your point, the manufacturers of these wood boilers know they are under "fire" due to the smoke issue, and have come out with new technologies that meet EPA standards(with dry and good qty wood as you mentioned, good point) , the interior seems a lot more costly though with free wood, hey...I'm think that the selling point of these units is that you can but a 18 wheel full of pine or poor wood cheap, cut them once into 4-8" diameter 2-4' lengths (crane please?) and slam them pretty much green in, good to go. With any technology. green wood will likely smoke. As an aside, a guy in work is going solar, putting a $12K panel evacuated tube collector system on the roof with 1000 gal insulated tank (gotta see this one). Another newbie is going keystoker (he beat me). I have another question for ya...(full of questions this am). What conventional (inside the home) stokers's exterior housing gets hot or really warm from the coal burning in the tray ? I may get one in the next several years and I'm looking at stokers from one of several perspectives to get the maximum amount if infrared radiation from the exterior housing, that means the case itself needs to get really warm though obviously it won't get as hot say as the Mark series. Any comments?
Uglysquirrel
 
Stove/Furnace Model: Pocono


Re: Visit to a Outdoor Wood Boiler

PostBy: Richard S. On: Sun Jul 06, 2008 6:09 am

There aren't any coal boilers that I'm aware of specifically made for the outdoors but I don't really see the point other than to isolate if for the dust problems but you can do that inside a basement too. Persoanlly I'll never put any type of appliance that burns solid fuel anywhere but the basement. With wood you obviously want to get those types of boilers as far away from the dwelling as possible. Most of the stokers are insulated, our basement stays very comfortable even with the insulation. It's pretty close to the basement steps and you get a rush of warm air when you open the cellar door in the winter because it collects there. You can take the insulation off if you wish.

You'd have to be more specific as to your reasons why you want the radiant heat, they insulate them for efficiency and to keep the heat out of the basement in the summer. Between the flue pipe and all the plumbing you get a lot of radiant heat when its running constantly. I can go down there now and touch any pipe or the flue pipe but you couldn't do that when it was really cold.
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

Re: Visit to a Outdoor Wood Boiler

PostBy: Freddy On: Sun Jul 06, 2008 7:34 am

Go north my friend! http://www.heatinnovations.com/od-boiler.htm This Canadian outfit makes an outdoor coal boiler.

I'd think the solar unit will work pretty well. Of course he'll need some sort if back up. If the backup doesn't get used much, natural gas or propane would be sweet. Geepers, 4 or 5 yrs ago if you invested twenty grans in a solar unit you'd have been looking at a 15-20 year payback. Now 3 or 4 years of oil prices will pay for about anything! It's sad that so much of our money has to go in that direction. It's going to hurt Maine more than any other state. A far higher percentage of people here burn oil, and our winters are two months longer than any other state....'cept Alaska.

I'm the wrong guy to ask what stoves are hotter than others. This coal thing is all new to me. I've never burned one pound of it yet! When I was a kid a friend of my fathers burned coal for years and years. Looking back and trying to remember when I was 8 or 10 yrs old, I'll bet it was an EFM. It had auto ash removal too, at least into 30 gallon pails. If it weren't for seeing that when I was young I'd have not given coal a thought. I'm sure I'd be burning wood....again.

The dog, "Keeoh" is her name, says "Woof!". We just got done playing Frisbee. She's so funny, smart too. I'll throw the frisbee half a dozen times, then tell her "I tire of red frisbee, I want to play with white frisbee". Well, she'll spit the red one out like it tasted bad and she'll snoop allllll around the house until she finds white frisbee. 10 minutes later we play the same scene with blue frisbee. I know, I know, dogs are color blind.
Freddy
 
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined

Re: Visit to a Outdoor Wood Boiler

PostBy: Richard S. On: Sun Jul 06, 2008 8:17 am

It's billed as a bituminous boiler. Be interesting to see some pictures. Most of the OWB are billed as coal burning appliances but some of them are simply not suitable for anthracite coal, others will work very well. It depends on how they designed the firebox. I suspect many of them test with bit. coal and it works for that.

This one for example is no good for anthracite:

Image
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

Re: Visit to a Outdoor Wood Boiler

PostBy: Uglysquirrel On: Sun Jul 06, 2008 6:06 pm

Richard, as I saw on another thread the designs that have a V or moon ( as the above pic is) shape seem to be problematic and while I'm no expert, I can see why the ash not in direct line with the grates are going to have removal issues. Design is important. Thanks for the reminder.

Freddy, you have a lot of coal for not burning any, me to (7.5 tons, want to go up to 12.5) but you have MORE. I(nterestingly the site you gave, the coal model has a 700 lb capacity and 600,000 BTU max output...hummmm...maybe I'll keep my pool open all winter. And I must admit you dog is kinda smarter than my smartest dauchund, The smart one comes when you shake the biscuit box, thats about it.

See ya at the coal pile,gentlemen.
Uglysquirrel
 
Stove/Furnace Model: Pocono

Re: Visit to a Outdoor Wood Boiler

PostBy: Richard S. On: Sun Jul 06, 2008 7:34 pm

It's not the ash that is necessarily the problem but the air. The coal on the sides won't get enough air and won't burn. Now if you built a wall all the way down both sides of the grates you'd be in business or if filled it up with 300 pounds of coal it might work ok.
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

Re: Visit to a Outdoor Wood Boiler

PostBy: Uglysquirrel On: Mon Jul 07, 2008 5:21 am

I see said the blind man !!!!!!! it makes sense...

The profound knowledge within this forum is astounding.
Uglysquirrel
 
Stove/Furnace Model: Pocono

Re: Visit to a Outdoor Wood Boiler

PostBy: e.alleg On: Tue Jul 15, 2008 10:49 am

OWB work better with seasoned wood. The problem is human beings take the path of least resistance. Why cut and split logs and stack them to dry for a year when you can just throw them in green and whole?
e.alleg
 
Stove/Furnace Make: EFM
Stove/Furnace Model: 520