Out door wood boiler to steam boiler

teebone1500

I just bought a 8,000 square foot home with 2 newer hot water and steam boilers. The steam boiler heats most of the house and works great and cost 900 a month to run. If I purchase an outdoor wood boiler can I connect it to the steam boiler to finish the heating process and creat steam. Do they make a steam heat exchanger. Desperate for answers

Trenton

Jamie Hall

A better bet would be to connect the wood boiler in series first, to heat the returning condensate, and let the fuel fired boiler finish the job. There will be some very interesting control issues...

Ironman

Wood boiler + steam boiler, not viable.

leonz

NOPE, NOPE, NOPE, do not even venture to think about that. Take this as coming from a 33 year wood and coal boiler user that switched to a coal stoker boiler.

Have you had a heat loss study done yet?? That would be the first thing to do and then go from there.

Trent, If you can purchase anthracite coal locally-please send me a PM with your email and I can help you with this as anthracite coal is much more economical to use to make steam and hot water..

The money your spending on fuel in one or two years- can purchase a single coal stoker boiler that will create over 130,000-260,000 or more BTU to make steam and you can leave the other boilers as back up units.

Solid_Fuel_Man

While it is possible to heat the condensate as @Jamie Hall pointed out (never thought of that!) It's not really feasible IMHO.

Steam has the drawback of not playing well with solid fuelled boilers. Ironic as pretty much all steam was originally coal fired. Outdoor wood boilers (OWB) are also mostly unpressureized which rules out any steam directly. Also their efficiencies are poor to absurdly poor!

leonz

Their 4 good lines of coal stoker boilers that have been making steam for 5 plus decades and work efficiently to make steam with an ASME H stamp rating.

In this instance a coal stoker will require much less work to maintain than a forest eater/water stove and you will not have to get up at 3AM for feed them in the middle of a blizzard.
(been there done that)

www.efmheating.com
The DF520 coal stoker is an underfed/tuyer/pot stoker that operates at a wide range of coal feed settings to provide both steam and hot water and it also can be equipped with and oil burner. The EFMDF520 comes with an ASME rating and H stamp. The EFM DF520 also has a domestic hot water coil as standard equipment.

www.axeman-anderson.com
The Axeman Anderson Anthratube coal stoker is the first traveling grate coal stoker for home use and comes in two sizes 130M and 260M and are rated for steam and hot water with the ASME H stamp and Both units have a domestic hot water coil as standard equipment when used for steam heating.


www.alternateheatingsystems/downloads/CoalGunBro.pdf
ASME H stamp certification can be provided for an extra charge
and come with a domestic hot water coil as standard equipment. The AHS coal guns are a copycat of the AA design
except where they use a hopper for coal delivery to the combustion chamber.


I rate the keystoker coal stoker as the last option based on personal experience with them(I have a KAA-4-1) dual fuel unit).

Solid_Fuel_Man

I will vouch for the EFM coal stickers. Very clean for coal and also I have had success making them run well on pellets, but that is on your own!

The AA tends to make a considerable amount of coal dust around it, something to be considered.

Just what I've encountered.

leonz

I have a lot of coal dust in the floor of my keystoker at times too due to the forced draft combustion under the 3 bed wide coal grate on the KAA-4-1.


The Axeman-Andersons will make a lot of coal dust due to the rotation of the open auger tube but it also burns well after you sweep it up and toss it back in the bin.



I will probably continue to use the 4 gallon steel pails from Tractor supply for ash as they are much less expensive to buy and easier to use.

AnthraciteEnergetics

The cost of running the steam boiler is a building heat loss/insulation problem, or you're just heating a massive home.

As mentioned the typical outdoor wood boiler (the water jacketed smoke box kind, not gasification types) are 22% efficient, meaning 78% of the wood you burn warms the outdoors. They are waste wood incinerators that produce smoke and space heat as by-product. Too big for most homes and terribly engineered. Outlawed in a lot of municipalities in PA.

Insulate the house and steam mains, get venting issues sorted out, service the boiler and chimney and it'll all be good.

I like the idea of running steam from a coal boiler. Have seen it once or twice with the Keystoker boilers.

teebone1500

The house has all new windows (71), roof, and insulation. From ban joist to attic. It even has every steam pipe newly wrapped and insulated. the issues is that the steam boiler heats 6,500 square feet and we barley live in a quarter of that. Can I shut off individual radiators ? will that save on usage? the other half of 1,500 square feet are heated by a oil fired boiler. both installed in 2006. I used to heat with a coal stoker stove at my old house but my wife hated the dust in the house and purchasing coal was a a mess of a job

Jamie Hall

Well... yes, you can shut off radiators (particularly if they are two pipe; one pipe can be problematic, but you can cut them down a lot by shutting off the vents -- just turning them upside down works with some but not all vents). The problem is that you will then wind up with a horribly oversized boiler. Minor oversizing -- even up to 50 percent -- isn't too much of a hassle, but if you are trying to cut from enough heat for 6500 square feet to 1500 square feet... I think you are going to have some real cycling problems, and will have to get very creative to get the poor monster to even remotely match the load.

jumper

Almost a century ago people did produce steam by burning wood. Boiler room was separate from house. Make up was melted snow so at least water side of boiler was clean.

Steam heating was a tremendous advance over stoves. Feeding one firebox could heat many rooms. I don't think efficiency was an issue since fuel did not require $$. But folks preferred to work for $$ to buy coal instead of working to garner wood fuel.

Boilers were sometimes old power boilers converted to zero pressure.

Speaking from stories I heard long time ago. Not from experience.