MULTIPLE UNITS TO SERVICE 400,000 BTU ?

What fuel do you want to use? How often do you want to load it? Is a budget a big issue or is the quality of the system more important? Is your heat load accurate? What type of terminal units do you have?

Garn units are very popular here and may be an excellent choice for your application. They are sized at Btu/hr Burn Rate* 350,000 425,000 925,000. www.garn.com. They are large units (integratd storage) but if you have a 400K load then you can probably make space for it. There are a lot of nice Garn installs on this forum.

What percent is base board? Low water temp is an issue for this product. IE the garn. The load is huge, is why I ask. To handle a load like this I would in stall a 1,000,000 gas btu boiler. if this is a home, how many sq ft ? I seen engineers miss the loads by half to CYA themselves.

I believe that Econoburn has a 500,000 btu unit.

If you want a real deal on a 500,000 btu gasser there is an ASME stainless steel Wood Gun on Ebay. I gave these people some listing advice. They are willing to "bargain" on this unit. Don't let the starting price scare you. It is not that old. I'm sure the pellet feeder can just be removed & possibly sold. I have no connection with this sale other than trying to help them out, Randy

Mainewood said:

bigburner said:

What fuel do you want to use? How often do you want to load it? Is a budget a big issue or is the quality of the system more important? Is your heat load accurate? What type of terminal units do you have?

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cordwood, manual loading, budget is always an issue... heat load provided by an engineer. baseboard and radiant heat. thanks.

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Apparently, it wasn't when you built the load.

I'm no engineer, but I am intimatly aware of heating 4k [/] with a wood-fired hydronic rated at 100kBtu. The oil unit is 114(?). Is 400kBtu like 10,000[] and all 10 showers going at the same time?? Windows open too??

May I come work for you? I'll keep the fire stoked :cheese:

Check on those load numbers, 400,000 seems big? Do you have a pool or snowmelting? How large is the building?

I'm guessing you will have a backup boiler? If so, and the load is that large, size the wood boiler for a portion and allow the backup gas or oil fired to kick in at design, or below conditions.

hr

For this sized load I like the idea of the 925k Garn. Even at design temps you would have enough capacity to get through relatively long periods (half a day?) without having to load wood into the boiler. You said this is a commercial space, so I assume that there are long periods after work hours and on weekends when no one would be around to load wood into the boiler? I also assume that any facilities or maintenance staff wants to spend as little time as possible tending the boiler. This large output boiler combined with the huge integrated thermal storage would probably get you through the weekend on all but the coldest days of the year. I assume you will have some kind of fossil fuel back-up too.

This load is much easier to meet with a pellet boiler(s), so you may want to consider that too (auto feed from a large pellet silo, just about as easy as a fossil fuel boiler).

hope this helps,

Chris

Mainewood said:

Thanks, everyone for your input. I need to do my homework in getting more information. You have given me a good outline to proceed with. I am involved in finding a wood boiler to heat a large commercial space. I'll post more info as it becomes available.

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From what I have been told commercial solid fuel heating, if boiler, must be ASME or unpressurized as the Garn. If correct, you cannot stack together just any boilers or use just any single boiler, Randy

I looked for some pictures of the AMC Crawford Notch boiler room. They have a very nice Biomass boiler set up.
There was mention of pellets. I would take a close look at that set up. You could have pellets delivered in bulk into a silo. An auto-feed system would keep you going 24/7 with no tending. Your initial set up would be more, no doubt, but you wouldn't have the fire tender on the time clock. The set up would be cleaner and give you a consistent output.
Find a pellet supplier and ask if he delivers to commercial setups and go look at what they have.

http://www.mass.gov/Eoca/docs/doer/pub_info/doer_pellet_guidebook.pdf
http://www.maineenergysystems.com/

A number of the public schools here in Vermont have woodchip-fired boilers- auto-fed by augers, etc.

A Google search will probably pull up the manufacturers, although I think I recall that the two big names are ChipTec and Messersmith.

I am guessing that woodchip prices may be lower and more stable (if oil goes way up again) than pellets (pellets seemed to rise with oil back in '08 if I recall correctly), but that's just my guess.

Depending on the type of commercial space. Fluctuating occupancy (retail, office, etc) will not make the best use of radiant heat IMO.

Maine does not require ASME for commercial solid fuel heating. It does for any municipal use. Commercial does require a listing such as UL, Randy

pybyr said:

A number of the public schools here in Vermont have woodchip-fired boilers- auto-fed by augers, etc.

A Google search will probably pull up the manufacturers, although I think I recall that the two big names are ChipTec and Messersmith.

I am guessing that woodchip prices may be lower and more stable (if oil goes way up again) than pellets (pellets seemed to rise with oil back in '08 if I recall correctly), but that's just my guess.

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Chips are a nice inexpensive fuel source, but as I understand it, a 400k BTU load would be a bit below the low end of where this equipment makes sense. I think they start at around 500k, but are normally north of 1mm BTU. Chips require very robust fuel handling mechanism$$ - that's why we don't see much at the residential scale.

Vermont leads the nation in schools that are heated with wood chips. Forty five schools, I think. BERC is a great resource, I would recommend you contact them for info too.

Chris

The local Rec Center uses a 650k Pellet System, we have a new school going in Leed Gold Plus and they will be using a Swedish Wood Chip system.

As far as I am aware wood chip boilers available in the US tend to be 500k plus, there are smaller ones but I do not believe they are imported here.

The Swedish one is interesting, I have a feeling I have thrown the brochure away. Big problem here is that a large pile of chips will just freeze solid.

The solution is to chip just in time. The material handling is done by specialist containers which are filled, transported to site. A full load will run for a bout a week in bad weather, it has a moving floor to feed the auger system.

Both those system of course have automatic feed, not something you can do with cord.

It is cheaper to get 2 of the smaller Garn's that one of the big ones. Their heat output is peak, so it depends in you have somebody on hand to keep loading it up when you need all those btus's. It may well be in a commercial setting the extra equipment cost balances out the labor saving using an automated process.

If your 400k is peak and your normal load is much less and you have an existing system, then it could make a lot of sense not to to try and meet full load, just use your fossil back up to take care of those peak demands. I know a Vetenarian who does that with an OWB, on a really cold night he is going to burn Propane for the lats few hours, but it simply is not worth upgrading just to take care of that.

I can think of another situation, a Hotel, open 24/7, also an OWB, they use the kitchen staff to feed it, just outside the door, so no additional labor costs. My guess is that their peak load is 750k, and no way is the OWB going to provide that, but it does take care of a lot of their more normal load and contributes to the peak load. Their bigger problem is that they are in town and they do not have much space for storage.

Tarm Sales Guy said:

pybyr said:

A number of the public schools here in Vermont have woodchip-fired boilers- auto-fed by augers, etc.

A Google search will probably pull up the manufacturers, although I think I recall that the two big names are ChipTec and Messersmith.

I am guessing that woodchip prices may be lower and more stable (if oil goes way up again) than pellets (pellets seemed to rise with oil back in '08 if I recall correctly), but that's just my guess.

Click to expand...

Chips are a nice inexpensive fuel source, but as I understand it, a 400k BTU load would be a bit below the low end of where this equipment makes sense. I think they start at around 500k, but are normally north of 1mm BTU. Chips require very robust fuel handling mechanism$$ - that's why we don't see much at the residential scale.

Vermont leads the nation in schools that are heated with wood chips. Forty five schools, I think. BERC is a great resource, I would recommend you contact them for info too.

Chris

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We looked into chip boiler for our school. Too expensive for the install. Trailer truck loads of chips are not an easy thing to handle. Unless you store them inside, they will freeze. trust me, as i haul this stuff for a living. Be curious how VT is doing it. Also,EPA new rules are raising havoc on new installs up here. The price of clean wood chips is has increased in this region. Hog fuel(bark,etc ) has also increased, in part due to the gov subsidies in a couple of pilot programs.

I vote for the GARN also.

Insulate the heck out of it and get another heat load done. The insulation will let you go with a smaller wood stove and will save you an awfull lot of wood and time. Make sure it's very well insulated.

Just remembered the name, Osby Parca.

I know they have a wood chip boiler working in Northern Colorado and Sweden gets very cold as well.

One of the initial problems they has was with getting cleans chips, and of course the dimensions need to be within the parameter of the feed system.