Homemade outdoor wood boiler idea

[j_h1980]

Ok I have an idea for an outdoor wood boiler.

Basically it would be poured concrete or block firebox with a wood shell.
I'm guessing the concrete firebox might tend to crack or something but I could always line it with firebrick if that was to happen.
I would have about a 32" tall firebox with a 1/4" thick steel plate across above the entire area except for a bit at the back. I would then have about 8" more open space above the sheet of steel for smoke and then above that lay flat some cast iron radiators 1 or two layers thick covering the entire area. Above that I would put a pitched steel layer to funnel smoke to the chimney which I would probably put at the front. I would put a 275 gallon water tank standing directly behind the concrete structure and enclose the entire thing in a well insulated structure. I'm not sure of the pump set up, I would maybe have 2 pumps one to circulate to the house from the tank and another to circulate between the radiators and the tank. I would probably put in a blower or 2 into the firebox as well. Is this totally crazy or could it work? This would be fairly simple and cheap to build with not much welding needed.

 

[stonykill]

my grandfather made something similar about 25 years ago. It was an idea from mother earth news. It was forced hot air tho, and not a boiler. If you search the mother earth news archives for "hasa" (spelling may be wrong) you should find it.

 

[charlesfarm]

Before using anything homemade for heating, be sure to check with your insurance. Some will drop you if they find out you're heating with anything that is not UL approved. If you ever had to make a claim for damages that were caused by the stove, it would probably not be covered unless you got approval beforehand.

God bless,
Chris

 

[habanero]

Chris's suggestion is a good one. I heat my house with a homemade wood boiler-but all the insurance company cared about was that the wood heat was only a "secondary" source of heat. As long as I had a furnace as backup, they didn't care. Now if I blew out the side of my garage from a steam explosion, somehow I doubt they would be anxious to cover it.

Now as to your design, I'm having a little trouble visualizing the whole thing, so I may be missing something. One problem I see right off the bat, though, is your concrete idea. Regular concrete has no chance whatsoever to stand up to firebox-type heat for more than a few hours. It will literally turn to powder before your eyes (don't ask me how I know). If you are set on masonry materials, buy some real castable refractory and be done with it. It isn't cheap, but stands up well to high temperatures.

Another word of caution is with the iron radiators as heat exchangers. I think you will be disappointed with their efficiency. I could be wrong, but I just don't think you'll get very good heat transfer. Whatever you use as heat exchangers, you get the best heat absorption if they can "see" the flame (thus utilizing radiant heat).

 

[ericjeeper]

Not a very efficient setup, but

If you elevate the insulated storage tank. You will not even need a pump. The hot water will thermosyphon up.

 

[keaton64]

My father-in-law build a homemade outdoor boiler using 2 halfs of 2 differert sized propane tanks. the inner tank was the firebox, the area between the tanks filled with water, then the outside was covered commerical boiler cover insulation. that thing works like a charm.

 

[bassman]

It will work.
look at a so called well manufactured outdoor boiler and they are nothing more than a tank with a fire under it.
what makes the good ones stand out is more on what dosent stand out.... smoke!!
a garn unit takes the idea that a fire can not be turned on and off and with there design they make a fire and blow on it real hard for a couple of hours to heat up 2000 gallons of water and then you use that to heat your home for however long it takes to cool the water .

i am no expert all i know is i want to make less trips to my main source of heat and i also want the option to go away for a couple of days .

I bought a pellet stove and the idea of taking a small amount of fuel and burning it hot sure works for that design.

40 lbs of pellets can go 24 hours try do that with a regular wood stove .

I paid 6 grand for just my outdoor boiler and I saw a farmer make a box out of cinder blocks and put 2 water heater tanks on top of it seal it up with clay and the thing works just as well as mine .
cost him 60 bucks for blocks.
next time i open my wallet for anything it better let me have a weekend off.

shayne