owb for 12000 sq.ft school?

[clusterbuster75]

 I have a chance to buy an old 12000 sq ft brick school( in real good shape, new roof and I had it inspected by a trusted mason) , but am scared to death of heating it.  I was the basketball coach there when they closed it a decade ago. Its been under the care of a non-profit since, and they are disbanding. They've offered it to me for very cheap (I could spend more on a large owb than this school).
I'm in southern Illinois and have Plenty of oak.

It currently has a natural gas fired boiler(installed in late 90's according to a former school board member) with radiators throughout building(3 floors and nice gym).  After spending 1/2 my sunday doing research(mainly on FF, reading old threads), is it possible to heat with an owb, or should I only consider wood as a supplemental heat source?

Can an owb hook into the current boiler system? Or will they need to stay separate by some type of heat exchanger due to boiler being pressurized and owb not?

Any other thoughts/advice/direction from those wiser or older would be appreciated...

[shelbycharger400]

i dont know much about outdoor boilers,  but i do know that you can get pressurized systems for outdoor boilers, but it costs more than non pressurized.  menards now sells the complete inside wall pannel for the manifold, connections, ect for lp/natural gas  on demand

If the price is right on the school, would be a debateable .  Flat roof?  those are only good for 15 to 20 years, and are expensive!  I would check out and ask for their records on propane/ natural gas usage, and draw a conclusion as to how much this is going to cost you to heat.    parents house was 4,000 square with the 2 storys,   if it burned wood all the time in the winter it was 2 bays of wood.  each bay was 14- 16 ft long , and contained at least 8 rows at over 5 ft tall, fence posted, all stacked tight 
thats a few grand in comparason for any liquid fuel usage.   

[John Mc]

A wood chip boiler would probably be a better fit than an OWB.  But they are not cheap.  These are pressurized boiler systems. 

A number of schools and other institutions in VT have them.  Unfortunately, there are a lot of folks out there making and selling them who just don't know what they are doing. 

Pellet boilers are another option. Personally, I'm not a fan of pellets, but they can be a good fit in some cases.  Pellet boilers are less expensive up front, but the fuel is more expensive than wood chips.

[Grunex]

check with city and state for slash from clearing operations......   might not be the best wood around, but lots of times you can get it in log form and free,  and if you invest in the right OWB  such as a pallet burner you don't need to cut and split all the wood...just load it up with a skid loader whenever needed. ....just my two cents.

[tyb525]

We had a member on here that did the same thing, bought an old brick school, turned it into his shop and lumber warehouse. I think he just heated it with a woodstove.

[doctorb]

My first reaction is to ask why you need to heat the entire school?  Certain, a great deal of that square footage can be insulated and kept at relatively low temps to keep the system from freezing.

Secondly, schools are often in neighborhoods and sometimes neighborhoods and OWB's don't mix well.  I would check into that issue before sizing your hypothetical OWB.

Third, have a very xlose look at the heating of the various rooms/floors.  Without too much trouble, can the heat be diverted to where you want it easily.  Repiping and New thermostats are not cheap.

[clusterbuster75]

Thanks for inputs.. I had several thousand bd ft of oak custom milled last winter and the tops(and a few hollow logs) are lying around waiting to be burnt.   The school is on 3 acres on the east edge of town(215 people) with nothing but fields to the east. I hoping their is no ordinances, but haven't checked.  Thanks for your inputs.  I was hoping to hear from doctorb. You had so much smart advice on other owb threads. Love to share some pics but Harvest starts today...  8)

[submarinesailor]

I think you should talk to the folks at Bioburner: http://www.bioburner.com.  It's a small family owned company at makes outstanding products.

Bruce

[beenthere]

In your research of the school, what did the records show for heating bills? Surely they would reveal what BTU's would be required to heat the building. Will indicate how well insulated the walls are as well as the condition of the windows. If not replaced in the last 10 years, prolly a lot of heat loss there.
When I think of "old brick school", a monster comes to mind, but 12,000 sq feet then maybe 100' x 120' and roughly 4 classrooms comes to mind. Height of ceilings would figure in to the calculations.

Pictures?
Time available to feed a wood burner - both during the winter months as well as available to work up maybe 20 full cords of wood a year.
A good job for the calculators.

[clusterbuster75]

I'd move in, so I'll be there to load it. My job is kinda seasonal(grapefarmer/winemaker) Last year was very warm winter here. I never got ice on my pond and they spend $2400 for natural gas, but that wasn't keeping it really warm all the time, just heating it up for special events and functions in gym.  Couple dozen big single pane windows that need painted and caulked or replaced(worst part of whole deal IMO).   10-12 ft ceilings(depending on floor).  12000 sq ft comes from insurance man who has current policy on it. There is 6-7 classrooms, big halls, partial basement with cafeteria and gym.  I told em I'd take it, but still uncertain if its wise.

Thanks for all your thoughts...

[martyinmi]

   Central Boiler (3200) or Portage and Main (Optimizer 450) should easily heat that building. They are both gasifiers, so they smoke very little. If you were to keep the entire building @ 70* during the winter I'd wager you'd go through somewhere between 20 - 40 full cords of wood if your climate is similar to that of ours here in Michigan.
   At 50 years old, I'm beginning to slow down a little (OK, maybe more than a little for those who know me!), and last winter I cut around 30 cords, and processing that much wood consumes a bunch of your spare time. A large OWB requires a LOT of commitment to keep it fed. If the boiler you choose is not a gasifier, that level of commitment increases by 40 - 50%.

[gspren]

  I will only answer the hook-up part. Since you are already using a boiler with hot water to heat it is easy to put a water to water heat exchanger in so that a non presurized OWB can heat the water in your presurized gas boiler and still use the radiators.

[John Mc]

Any idea what kind of efficiency losses you get in one of those heat exchangers?  I'm not trying to talk down the idea, just curious about the effect a heat exchanger has on the overall performance.  I guess either way, it's going to be a lot of wood to heat that much space.

[beenthere]

John mc
Where would the loss be?
Seems to me, only in the lines to and from the exchanger, or in the OWB itself.

Seems the capacity (size) of the exchanger (water to water) would be the main decision.

I may be missing something here. ;)

[leonz]

I have a chance to buy an old 12000 sq ft brick school( in real good shape, new roof and I had it inspected by a trusted mason) , but am scared to death of heating it.  I was the basketball coach there when they closed it a decade ago. Its been under the care of a non-profit since, and they are disbanding. They've offered it to me for very cheap (I could spend more on a large owb than this school).
I'm in southern Illinois and have Plenty of oak.

It currently has a natural gas fired boiler(installed in late 90's according to a former school board member) with radiators throughout building(3 floors and nice gym).  After spending 1/2 my sunday doing research(mainly on FF, reading old threads), is it possible to heat with an owb, or should I only consider wood as a supplemental heat source?

Can an owb hook into the current boiler system? Or will they need to stay separate by some type of heat exchanger due to boiler being pressurized and owb not?

Any other thoughts/advice/direction from those wiser or older would be appreciated...

I would not use outdoor wood boiler!!!


It will cost you much less money to install a Harman coal stoker using
anthracite for heating the place to abase temperature and simply create
zones for heating as needed or simply set the thermostat at 65 degrees
and simply be attentive of the stokers coal needs.

You could always install a wood stove/fireplace in your work and living space if desired but
the coal stoker will give you a lot of heat with very little ash.

[tyb525]

Ok so how much would the anthracite cost, delivered, and how much would he need???

You say it is better but you don't explain how.

[Local4Fitter]

I currently run a coal stoker to heat my basement (won't burn coal once owb is installed). It's a leisure line with coal-trol thermostat. I love the stove but I get alot of ash. Would a large coal stoker boiler make less ash? I burn about a bit over a ton to heat a 300 sq.ft. room.

[leonz]

I currently run a coal stoker to heat my basement (won't burn coal once owb is installed). It's a leisure line with coal-trol thermostat. I love the stove but I get alot of ash. Would a large coal stoker boiler make less ash? I burn about a bit over a ton to heat a 300 sq.ft. room.

In my case I bought a ton of bulk stove coal for $265.00
and picked it up with my dump trailer at my fuel dealer.
If he buys even the smallest Harmon stoker or Harmon wood and coal boiler
he will save money by setting up a zoned system leaving the unused
areas zoned for 50 degrees.   


If he has a new Harmon installed of either type he will have better burn and higher
combustion efficiency with the Harmons multipass design for the combustion chamber.


The big issue with any flat grate stoker with an underfed air supply is that the
coal may not be completely consumed.

If the coal was smaller 50-80 mesh it would burn more efficiently and there would be fewer
clinkers and unburned per or rice sized coal. 

If Harmon offered and used the underfed burn pots from Combustion Engineering with the combustion air blown through the auger tube into the base of the burn pot as an option they would sell more units and have an even bigger following.

AS I have said before the typical OWB combustion chamber is very poorly designed as they do not have an after burner like an incinerator and most have no fire brick to insulate the boiler walls and act as a heat sink aiding combustion. 

[gspren]

  The OWBs suggested my martyinmi do have an after-burner effect. One of the bigest differences for many of us in choosing between wood and coal is wether or not you have to buy the wood, nearly all have to buy the coal. The heat loss of the heat exchanger is into the room where it is located so normally it doesn't matter.

[clusterbuster75]

 



Any perspective on using pressurized owb versus non-pressurized and heat exchanger?

I'm a quick study. Any guidance on web resources about radiators and how to "Zone" them?

Thanks.

[clusterbuster75]

 

[John Mc]

Any guidance on web resources about radiators and how to "Zone" them?

Isn't the school already zoned?  I can't imagine the whole 12000 sq ft is all on one zone.

[leonz]

Any perspective on using pressurized owb versus non-pressurized and heat exchanger?

I'm a quick study. Any guidance on web resources about radiators and how to "Zone" them?

Thanks.

Do you really know what type of heat radiation you have?

It sounds like you have no idea what type of heating system you have.


+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
If you have the cast iron radiators with STEAM HEAT which the boiler appears to be a steam boiler you either have a single pipe or a two pipe system.

The temperature is controlled by a temperature regulator on the individual radiator.

The single pipe steam system is much more efficient BECAUSE IT IS SIMPLE TO MAINTAIN!!!>


The steam radiators in each room should have a temperature regulator on each radiator, if they
do not it is easy to install them.


A small coal stoker like one of the harmans could be tied into the system you have to make steam with no issues.

if you need more heat you would be able to fire the other boiler up if needed BUT with a larger Harmon coal stoker
it would barely be needed. 


8)








An after burner in a furnace/incinerator is secondary burn chamber that is
composed of firebrick which acts like the masonry paths of a russian stove.

I doubt sincerely that any OWB on the market would qualify as a unit with an afterburner
UNLESS it had a smoke scavenger with multiple tubes filled with water or
heated air to remove the heat of combustion before it goes up the chimney.

[clusterbuster75]

thanks leonz. I'll be an expert someday ;). Will be checking on things you mentioned.

[martyinmi]

leonz,
   Just a little FYI. I don't know of ANY gasification OWB on the market that doesn't have a multi-pass heat exchange system to pull as much heat as possible out of the 2000* plus heat generated by the near complete burning of the fuel. They ALL have a primary burn chamber as well as a secondary burn chamber that is either brick or ceramic lined to withstand the high temperatures produced by the gasification process. Their combustion efficiencies are well over 90%, and their overall efficiencies are near the 90% mark. The EGT's are typically reduced to 250* - 400*. (If you get a chance, google "downdraft gasification". Also, check out EPA's "burnwise" website.) There are even a few conventional OWB brands out that have a multi-pass heat exchange whose overall efficiencies are in the 55 - 60% range.

   Sounds like you are a fan of the Harmon coal stoker ;). (I borrowed your wink clusterbuster75 :D)

clusterbuster75,
   Keep us posted! That looks like a challenging and very fun project 8) Looks like you are doing more than your fair share to keep your community's history alive
    There was an old 3000 sq ft school that I could have bought DIRT cheap about 15 years ago, but my beautiful bride wouldn't let me. It didn't sell and ended up being torn down and hauled away. The small piece of ground is now farmland.