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Wood Gasification vs outdoor wood furnace/boiler

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by epatrick, Apr 8, 2009.

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  1. epatrick

    epatrick New Member

    Joined:
    Apr 8, 2009
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    Loc:
    Northern Ontario
    Hello folks,
    Total noob to these forums but i've just started seriously looking into an alternative-to-oil heating solution for my very aged farmhouse...and I came across your little corner on the net and got hooked on reading all the posts.
    Question: Is there such an animal as a wood-fired gasifier that can be used with an existing forced-air ductwork system, or do all gasifiers rely on a boiler hooked to water radiators. Is forced-air more efficient than radiator-based systems?
    I would really have liked to go the geo-thermal route (I have the real estate to do it) but it seems it's WAY too expensive for my aging home.
    All that being said, I also have an indoor dug well (about 13 feet deep, 36" across) that i do not use any more for my water supply - can it be used as a storage device for any kind of heating system I choose to adopt? My current woodstove is nowhere near air-tight and I go through ALOT of wood (from my own lot) in a winter - it uses a massive stone chimney though, that once heated acts as a terrific radiant source of heat.
    Thanks in advance for any help/advice received!
    Patrick.

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  2. Slow1

    Slow1 Minister of Fire

    Joined:
    Nov 26, 2008
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    Loc:
    Eastern MA
    If you have water that is hot enough you can put it through an air handler to make forced hot air so called "Hydro-air" systems. This is actually how my oil fired system works now - I have an oil boiler that heats the water and pipes it to air handlers in the house that then heat the air and feed through duct system into rooms. So - I think the answer to your first question is most likely yes such a system can be engineered.

    I'll bet whatever your current wood burning solution is that if you provide more details on it there are folks here who can suggest ways to improve it and reduce your wood burn rate (or confirm that it can't be improved, whatever the case may be).
  3. DMX_512

    DMX_512 Member

    Joined:
    Nov 17, 2008
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    Loc:
    Louisville, KY
    epatrick,
    I am in the process of hooking up my EKO 40 gassifier. I am going the Hydro/air method. I, like several others here, am using Heat Exchangers that will be placed into the plenum of my forced air system. It is similar to how your car is heated. Heated water is circulated through the heat exchanger and then air is forced through the fins and out through your duct work to the rooms of your house.
    As far as using your old well as non pressurized storage I am sure that others with much more experience will help you with that.
    I hope this helped a little.
  4. pybyr

    pybyr Minister of Fire

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    Loc:
    Adamant, VT 05640
    Since I previously had a warm air/ duct system, I've done the "hybrid water to air" approach, using my existing oil warm air furnace's blower to push air through a big custom-fabricated water to air heat exchanger placed in the ductwork over the oil burner's outlet.

    I purposely sized the water to air HX on the big side, and then some, so that it can belt the BTUs into the moving air even with 150 degree water, whereas the water-air HX units built for fossil applications assume 180 degree water. It cost me more up front, but works better already at heating the house as the fire is starting, and will work better with storage once storage is on-line.

    It works fine- indeed more than fine-

    You will spend more money in operating costs on electricity running a blower than you'd spend running circulators for hydronics, but, then again, you'd spend a lot in conversion costs in going from ductwork to baseboards or radiant floor.

    the vendor who I got the water-air HX coil through, who was superb to deal with, is Ross at
    www.nationwidecoils.com
  5. epatrick

    epatrick New Member

    Joined:
    Apr 8, 2009
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    Loc:
    Northern Ontario
    Thanks all for your thoughts on water-air heat exchangers...i think that i will go the route of placing an HX in my duct-work and using the existing oil-furnace blower to push it...just glad to hear others have done it and are successful...will post details of my conversion and results later.
    One further question - in reading up on gassifiers, I notice that, among all the gases created as a result of the gassifier's purpose, one is carbon monoxide - what, if any, possible danger is there of leakage of these gases into the environment outside of the furnace that might make me want to place the unit outside of the home rather than in my basement?
    Thx again,
    Patrick.
  6. pybyr

    pybyr Minister of Fire

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    Carbon monoxide is created by regular wood combustion, too, so I wouldn't think that a gasifier poses any higher risk than any other wood burning appliance (indeed, once it's gasifying, then the CO is combusted into CO2, which is less risky). In a properly maintained unit, I think there is very little risk of the CO leaking out- no more risk than any other wood appliance, or for that matter, any combustion appliance.
  7. rwh442

    rwh442 Member

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    Loc:
    Southeast Indiana
    Epatrick,

    Just make sure when you install the water to air HX in your furnace plenum that the water flow is opposite (counterflow) to the air flow. I made the mistake plumbing the inlet water flow on the same side as the air flow supply through the HX. Others have made the same mistake and have done tests before/after the plumbing change and calculated I believe an 11% heat transfer improvement in one post. I can't wait to replump mine this spring or summer. FYI.

    Rob
  8. bulldawg72

    bulldawg72 New Member

    Joined:
    Jun 16, 2009
    Messages:
    4
    Loc:
    Western NY
    In a past life, I've designed and sold a number of "hybrid" systems (using a boiler to produce the heat and a forced air system to distribute the heat). It works. Though it does use a bit more electricity and the forced air side of the system does introduce some heat lost through the ducts. In any case, make sure to size the hyronic coil to your building's heatloss value and the supply/return boiler pipes to the coil's capacity. For example, if your heatloss is 80,000 btu and the coil's capacity is 100,000 btu, then the supply and return pipes should be 1-1/4" (capable of delivering 120,000 btu).

    To get started, I would suggest contacting Mark at Econoburn. He seems very knowledible on the Econoburn boiler and will be more than happy to help you design a hybrid system. The Econoburn website is www.alternativefuelboilers.com.

    For reference, Econoburn is eligible for a $1,500 federal tax credit and currently has a $500 or $700 factory rebate depending on model... and that can't hurt!

    Good luck!
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