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OWB questions

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by eyecal, Dec 9, 2007.

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  1. eyecal

    eyecal New Member

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    I just found this forum and have enjoyed all the great reading. I am building a new house and outbuilding and will be installing an owb. I have read everything I can on as many models as I can find. Close to me there is a central boiler, heatmor and hardy dealer. It seems driving around that I see more hardy heaters than any other brand. I would like to hear peoples opinions on all the brands and hear the good and the bad about them. We are building in the country, and I will not have to worry about smoking out my neighbor's. Also would like a owb that is capable of burning coal as well. Any help would be greatly appreciate. Thanks Mark.

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  2. brad068

    brad068 Feeling the Heat

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    First off , quit looking at owb's unless you like to cut twice as much wood as you need. Go gasifier. 40% compared to 80% eff. Its like comparing a diesel engine to a gasoline. You don't see big gas engines in semis or heavy equipment.
  3. Nofossil

    Nofossil Moderator Emeritus

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    Agree on the gasification. You can install one in an outbuilding. Much less wood, virtually no smoke, happier neighbors - all good.
  4. Eric Johnson

    Eric Johnson Mod Emeritus

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    I agree with Garnification and nofossil, but if you're thinking about coal, I'd check with Royall (Horstmann Industries). Their OWB is virtually identical to their indoor boilers, I believe, and they burn coal.

    The EKO, which is a nice gasifier, will burn soft coal. Presumably the BioMax, which is very similar to the EKO, will burn soft coal as well. It's available in an outdoor model:

    http://www.newhorizoncorp.com
  5. eyecal

    eyecal New Member

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    I am a little confused as to how the gasification boilers work. Are the outdoor models like a owb that you pipe the water underground to the buildings being heated? How does the price compare to the owb, is this an install that I could do? So what are all my choices as far as brands in the gasification boilers? Thanks Mark
  6. Eric Johnson

    Eric Johnson Mod Emeritus

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    Basically, the difference between a gasification boiler and a conventional wood boiler or OWB is the secondary burn, or "gasification." In a conventional boiler, the wood is burned in the firebox and the smoke and much of the heat go right out the stack, resulting in much more pollution and much lower efficiency. In a gasifier, the smoke is produced the same way, but then sucked down through a ceramic nozzle and into a special chamber where it is ignited. The smoke and other gasses burn at very high temperatures and the resulting heat is recovered in the water jacket before it can escape out the chimney.

    With any outdoor unit, gasification or not, the piping strategy is pretty much the same.

    You'll pay more for a gasifier, but burn about half as much wood to produce more heat and almost no smoke. And you need dry wood.

    All things considered, gasification ups the ante considerably, but in most cases it's the smarter longterm choice.

    There are plenty of threads around here discussing different brands and even some with pricing discussed. Most people in this forum who own gasifiers DIYed their projects to some extent. I did mine all by myself in my spare time, and I push a keyboard for a living. If you're reasonably handy, you can learn how to an installation right here. Spend a few hours reading and then you'll know where to begin. No questions go unanswered here, but there are no guarantees on the quality of the information.
  7. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    There are only a few outdoor gasifiers. Adobe has a line, I seem to recall that BioMax has an outdoor model, and Alternative Fuel Boilers will be releasing an outdoor kit for the Econoburn boilers in the very near future.

    You can also install them indoors, if you have the space.

    Joe
  8. Eric Johnson

    Eric Johnson Mod Emeritus

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    Blue Forge.
  9. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    According to the manufacturer, they mean "outdoor" as in "we don't consider this safe to install in a residence," not as in "weatherproof"... they want it installed in a shed or such.

    Joe
  10. Reggie Dunlap

    Reggie Dunlap Feeling the Heat

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    Like the man said don't bother with an OWB. Buy a Tarm or an EKO and be done with it. You'll burn half the wood and the initial set-up/purchase cost won't be much more than an OWB. And you and your neighbors won't have to deal with the smoke. I don't think any of the gasifiers can burn coal, but I'm not positive.

    My Tarm is located in my garage, I can drive the wood right to it. Since you are building a new house you have lots of options for water storage.

    Reggie
  11. Eric Johnson

    Eric Johnson Mod Emeritus

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    You can burn soft coal in the EKO. I bet you can in a Tarm, too.

    Actually, anything organic that will burn can be used as a fuel in most gasifiers, including pellets, corn cobs, pinecones, etc. Apparently not hard coal, however. The main challenge is getting a good fire or bed of coals going before you pour in the particulates.
  12. eyecal

    eyecal New Member

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    How far from the house can these boilers be installed. My thought wtih an owb was to set in undercover at my outbuilding and pipe it about 120 feet to the house. Am I able to heat both these buildings and be this far away from the house?
  13. Eric Johnson

    Eric Johnson Mod Emeritus

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    Closer is always better in terms of efficiency and expense, but I don't believe there's any practical difference between a gasifier and an OWB as far as where it's located. Once you have hot water, getting it into the house is the same process. My boiler is in the barn, about 100 feet from the tank in my basement.
  14. brad068

    brad068 Feeling the Heat

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    If you are going to have an outbuilding then you will have no problem installing a gasifier. May I suggest a Garn. A complete self contained unit. Fire box and water storage. And you can build your outbuilding to suit it. Check out the movie at Garn home. In my opinion these boilers are the "cats meow" They have track records of 20 years +. And yes they are big, and expensive, and more indepth to install. But 15-20 years down the road you'll be saying, "this is the best investment that I have ever made." As far as burning coal in them I'm not sure but they can burn about anything else including corn on the cob.
  15. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    With decent quality pipe, the heat loss is relatively small. Pumping distance will end up being limited by your willingness to pay for pipe or pumps. The smaller the pipe, the more friction loss the water will suffer (remember, 120 feet will be 240 feet, since it's a loop). The friction can be overcome with a larger pump, or by using larger-diameter pipe that has less friction.

    How much heat do you need to pump through the underground pipe (ie, how much heat does the building at the other end need)?

    For example, if the heat load is 100kbtu, 10 gallons per minute would be a decent flow rate. Figuring for a 50/50 water/glycol solution, and an average temperature between the supply and return of 165 degrees... 1-1/4" pex will give you a head loss of 15.6 feet, while 1-1/2" pex will give you a head loss of only 5.5 feet. You'll need to add heat exchanger head loss to that for the far end, as well as that of the boiler and piping at the near end - call it 15 feet total head for that.

    So, you're looking at 20 versus 30 feet of head, depending on the pipe size. 20 feet of head at 10GPM can be handled by a Grundfos UPS26-99FRC on it's high speed setting, or a Taco 0011IFC. 30 feet of head at 10GPM is going to require a significantly larger pump, or two pumps. In parallel, so each only sees half the GPM, the two pump option would be a pair of Taco 0013IFC pumps. In series, so each pump flows the full rate, but the heads add, two Grundfos UPS26-99FRC's could be installed and run on medium speed.

    Doubling pumps gets expensive in terms of initial cost (have to compare that cost to the cost difference between the two pipe sizes), and the electricity required to run the two pumps. Larger single pumps like a Taco 1615 (at 1750RPM) would work, but the cost is pretty high, and replacement if/when it fails isn't going to be simply a matter of grabbing one off the truck, whereas most decent service trucks have a Grundfos UPS15-58FRC and UPS26-99FRC on them, as those two pumps replace so many others, just by using the right pump and the right speed...

    Personally, I'd err on the side of larger piping, using a single pump. It might be slightly more expensive to install, but the long-term cost difference in electricity and maintenance is significant.

    If the price difference between the 1-1/4" and 1-1/2" stuff is large enough, you could always run four 1-1/4" pipes, and use two in parallel for the supply, and the same for the return. That also means that if one somehow developed a leak, you could drop down to three or even two pipes, and only at that time add that second pump to overcome the added head loss.

    Joe
  16. eyecal

    eyecal New Member

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    With out knowing all the btu requirments for both buildings yet, both will be heated with radiate heat. Will I need to have a storage tank in the house or will the boiler it self be able to keep up with the demand? I hope I could get away with out needing a storage tank. Will a storage tank affect how many times the boiler will need to be loaded? What are expected load times on these boilers?
  17. Eric Johnson

    Eric Johnson Mod Emeritus

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    There are a number of threads on this topic that pretty much address your questions. The short answer is that you don't absolutely need a tank, but it makes things a lot easier if you do. Without a tank, expect more effort and higher wood consumption. But it's one of those things that you can always add later, depending on how it does without it. There are people in both situations here, and all seem pretty happy with their lot in life.
  18. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    If you know the square footage of the house, I can ballpark the btu's - it will be rough, but probably close enough to size the piping.

    Joe
  19. eyecal

    eyecal New Member

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    The house will be 3700 sq ft that will be heated and the outbuilding will be 1500 sq ft.
  20. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    So, for round "maximum" numbers, call it 200k total, with 145k going to the house and 55k to the outbuilding (with the boiler). Not a replacement for an actual heat loss, but a ballpark starting figure.

    That would put you into definitely needing the 1-1/2" pipe. I think the UPS26-99FRC would still handle it, if you were careful with your piping and your heat exchanger selection (spend a little more on a larger heat exchanger, which can provide the same performance with less head loss).

    Of course, the actual numbers will determine it, and are likely to be lower than those guesses. I think the 1-1/2" pipe is definitely going to be the only reasonable choice, though, unless the construction is very impressive in terms of low heat loss...

    Joe
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