Newbie

I want to be able to load large chunks (50lbs) into the boiler and do not want to split any

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That would be a major problem, why is that a requirement?

In general there are 2 types of wood boilers. Outdoor Wood Boilers, OWB. ( Smoke Dragons ). These do take the larger pieces of wood that you are mentioning. However in many states they are becoming illegal because they smoke a lot when not making hot water.
Most boilers heat when a blower fan kicks on. With the OWB when blower fan shuts off boiler will continue to smoke.
Gassifiers. These boilers also have a fan. Once you get a fire going in the fire box you close a damper on the top of the fire box and the flame is forced down into a secondary burn chamber where all the coal & wood gas is burnt at 1200 + degrees. These stoves are really efficient. However they do require 4" splits and dry wood ( seasoned 2 years ).
For your year round hot water needs you would want to add a hot water storage set up. This can be 2 used 500 or 1000 gallon propane tanks. Idea being you burn your wood heat the water in the tanks and then use the water from the tanks for a day or so in winter and in summer you could go for a couple of days between burns.
The upside to Gassifacation is it burns really clean and highly efficient use of wood. ( Like 1/2 of the OWB's )
Some of the Gassifiers are, Tarm, Eko, Econoburn.
There is a unique stove called a Garn which may be a good fit for you also it combines gassifacation as well as storage.
Price many setups run $10,000 to $15,000.
Search on youtube for Garn and other stoves, above, and watch gassifacation in action.

Not splitting wood means you will use twice as much to produce the same amount of heat and a lot of nasty smoke.

RobC said:

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Gassifiers. .... they do require 4" splits and dry wood ( seasoned 2 years ).

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Definitely agreed on the small splits for a gasifier, but I think the 2 year wood is greatly overstated.

Depends hugely on what species of wood and the drying conditions.

I started the winter on some white ash that I'd cut and split only a few months earlier. It was definitely not optimal (wanted to save my better wood for the colder weather), but was not a problem, either. Moisture level when burned was in the low 20%, taken from the inside of re-split pieces, using a Beckman digital multimeter and the resistance chart from the US Forest Service

I am now running some yellow birch that I cut and split in July. Moisture level, using same method as above, is at or under 20% and the stuff heats like a dream.

And this was in a year with a really soggy fall, and while the wood was cut, split, and stacked quickly, it was not brought out of the woods until October (at which point it was stacked in a long tall narrow row that gets southern sun and a lot of breeze)

Would it be even better if seasoned for two years? Yes. Would the difference be vast enough to say that one should not buy a gasifier unless you can assure your wood has been seasoned two years? Absolutely not.

I do agree that some species like Oak, which are inherently really slow to dry, might need two years.

A gasifier does require some more effort at splitting and handling smaller pieces of wood. But it is so immensely more efficient that I'd never go back [my prior unit was a massive iron and steel wood/ hot air furnace that would take huge pieces of wood, but had a voracious appetite for wood].

Milkman8, I too am new to this forum, but unlike you I made my choice before finding this huge and very active knowledge base. I have ordered a seton wood boiler because like you I wanted to burn wood without a lot of processing. I realize I am about to get quite an education in wood burning.

I ordered the seton (http://www.rohor.com/) for the following reasons; 1). the seton can be pressurized to 30 lbs., 2). I wanted a big fire box, a 16" x 36" door in the big seton., 3). I wanted something that I could service myself. Fred sent me the plans, I could build another (with improvements e.g. a larger door and firebox) if I so desired. 4). I wanted something efficient enough to qualify for the federal tax credit(ten days left), but forgiving enough to let me burn marginal biomass out of our waste stream. (Nothing finer than heat from something that was costing money to despose of).

I respect the technology and efficiencies of the downdraft gasification boilers, but they require a high quality (expensive) feedstock. I know the seton is 30 year old design, and has several issues, but I'm believing return water temperature control, enough draft and heat storage are going to get me by most of them!

The Garn is a 30 year old design, but whilst both are relatively forgiving on wood, they are not so forgiving as the OP requires.

fred recommends unsplit wood - what other requirement?

A few thoughts:

As you can gather from the above replies most if not all of the responders will state (correctly) that a gasser is the way to go.

OWB's do produce alot of smoke, no getting around that. You state that the heating unit will be between the house & dairy barn. Chances are either your family or your dairy herd are breathing all that smoke from any OWB, very bad in either case.

You state that you want to have as little labor in the wood processing operation as possible, that I completely understand & agree with, so why not automate/mechanise that process?

There are plenty of Euro co's that make small firewood processors for the 3 point hitch on a farm tractor, pto driven & as portable as the tractor they are attached to. The Euro's have been doing biomass gasification on a farm scale for 40+ years now & have pretty streamlined systems, worth a long hard look IMO.

Sounds like you may need the volume of wood that would justify this type of investment. Will also save on labor in the wood processing end of the operation. More tons per hour = fewer hours needed. Tractor & operator back to doing farm work sooner.

If we were into the dairy end of cattle instead of the beef end I would never even consider an OWB of any brand. I just couldn't justify the risk of losing the dairy quota when the herd inhales that smoke & it makes it way through the blood stream & into the milk. Here there is far too much capacity in the industry & they are quick to close operations that have "tainted" milk until they are cleaned up & re inspected (long, slow, painful, process here) . Not sure about the situation in your neck of the woods, here I would never even give it a thought. Simple risk/reward analysis would tell me to make a different choice.

FWIW I also agree that a Garn in the situation you describe should get some serious attention. Very high volume/output units & you will need one (or more depending on how many head you are milking) to keep up to the hot water demands in a dairy operation. "Heaterman" one of the pro's that helps others on this site has some units (Garn's) installed on farms (sorry I dont recall if they are dairy or beef). If he picks up on this thread his insight into your situation would be worthwhile IMO.

In short: A gasser, that suits your operation in size (btu/hour), mechanised wood processing to reduce paid labor, that attaches to a tractor you already own.

This should go a long way toward giving you what you need in your operation, so the farms does not assume unnecessary risk & you can rid yourself of the "fuel" man.

Como said:

The Garn is a 30 year old design, but whilst both are relatively forgiving on wood, they are not so forgiving as the OP requires.

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The Garn sounds like a decent choice for you. You will need to rethink your unwillingness to split however or not burn wood in my opinion. You don't need to split every piece nor every limb, you just need to have dry wood for a gasser. IMHO don't even think about purchasing an OWB, this is a fuel waster that you would need to feed with twice the wood of a gasser, Randy

And with only 30 acres of woods, you will quickly use that up with an OWB. My state forester says I can sustain about 10 cords/year in MY 44 acres forest. Your forest is different (guaranteed - you are not myneighbor) but I bet it is not that much different. You have a unique situation with significant year round hot water needs. Makes the payback on a wood boiler much less than a heating only demand. Definitely a large gasser or Garn for you.

The issue of extra work splitting wood has come up before. Maybe I'm oversimplifying, but here's my take on the difference:

1) You can burn two unsplit 50 pound chunks of wood in an OWB.

2) You can split a single 50 pound chunk and burn it in a gasifier.

Option 2 will give you more heat. I suspect it's less work as well. It certainly generates less smoke.

If you're unable to get your wood cut, split, and at least moderately dry ahead of time, then either unit will be unhappy.

The gasifier will have a hard time maintaining secondary combustion, and might suffer a huge drop in efficiency - from around 90% combustion efficiency to perhaps only 50%. Smoke output will go from essentially zero to 'nasty'.

The OWB will also suffer a drop in efficiency, perhaps from 40% to 25%. It will also smoke a lot more.

The difference will be more noticeable with the gasifier, and that's why gasifier owners are so much more concerned with wood quality.

Check out milk cooler heat recovery systems, they might fit nicely into your plans. Assuming 20,000 lb milk per cow per year there is on the order of 3000 btu per cow per day that has to go somewhere and it might as well go into pre-heating your wash water.

http://www.p2pays.org/ref/09/08509.pdf


--ewd

The seaton don't require split wood but seems to have issues with the skins rusting out etc.

" Is there less CO2 pollution omitted by the gassifier "

Uh, you are burning WOOD. The CO2 sequestered by the tree while growing is released when it dies (burned or decomposes). Doesn't really matter how you turn a tree into soil amendments (mulch, ashes, compost).

If you are worried about CO2 emissions, stop exhaling ;-) (Just kidding, really)

Burning wood is better than pumping oil and burning it, IMHO.

And a gasser will use less wood to make the same usable heat.

milkman8 said:

So I guess it's best to get a gassifier. I like the fuel efficiency even if I have to split wood. Is there less CO2 pollution omitted by the gassifier besides fuel efficiency?

Also, we burn our trash on the farm. My neighbor has an OWB and burns trash in his. Is that ok? Can a gassifier do the same?

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NO trash, just wood. Randy

If I didn't know better, I'd say this was a set-up ;-)

Ok, deep breath here . . .

May I ask why you say 50# rounds? I understand not wanting to split. I rarely split. And since what I do split is usually Oak, it's incredibly easy.

As someone else stated, one of the big advantages of the RMND (SetonAdobeGreenWoodGreenFire, etc) units is that they can handle unsplit wood. But you don't want to get carried away with this. Go and cut down a red Oak and burn it the same day and you are going to be unhappy.

Look, it's nearly January. You are not going to purchase, install, and have operational until heating season is over this year. Go get wood twice a week during the winter. Learn all you can about secondary combustion (gassification) during the next few months. When heating season opens next year, you'll be ready.

There also should be no need for a re-heater to bring your DHW up to 160 for the barn.

http://www.p2pays.org/ref/09/08509.pdf I have installed these before, they work great - the ROI has to be quick - not exact numbers, probably listed in the PDF, but you get a ton of the energy back from the milk cooler. We had similar recovery on our commercial ice making equipment, pre heated the water for Ice harvest, every 22 minutes - same theory we were just on a bigger scale.

I have disagree on on the home style gasers for large operation, I am not advocating OWB either. I would need to be a upflow design which could handle greener wood and larger pieces. If it were me I would do a wood chip boiler that had a slanted grate combustion and a live floor for feed stock with storage. There are a couple around here and it is the best of both worlds. {gasification/large quantity} This is a big jump from an OWB, It's the only thing that gives the control required for a large farming operation. Pellets would also work, just too expensive. Straw bales? -- some nice video on you tube - better if you speak German

From personal experience, may I suggest that you put your money into new windows, insulation, and stopping air infiltration in your home first, then evaluate your heating needs?
By far the best value for money spent (ROI) is on insulation - keeping the heat in. Then you can choose the heating system that best suits your needs. You (like me) might not mind splitting for a gasifier if you are using a lot less wood than you would have if you hadn't insulated and replaced windows first.

Just adding to the discussion...

Singed Eyebrows said:

milkman8 said:

So I guess it's best to get a gassifier. I like the fuel efficiency even if I have to split wood. Is there less CO2 pollution omitted by the gassifier besides fuel efficiency?

Also, we burn our trash on the farm. My neighbor has an OWB and burns trash in his. Is that ok? Can a gassifier do the same?

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NO trash, just wood. Randy

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Burning plastic, which is a big part of modern trash, is a great way to make some seriously noxious and carcinogenic compounds.

It amazes me that people who'd wig out if there were some commercial plant belching such toxics in their neighborhood seem to still not think twice about "homebrewing their own" by burning trash.

Burning trash requires equipment on a commercial scale, well to do it without gross pollution.

Hopefully he is not up wind of you.