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Greenwood 100 users without storage

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by mpilihp, Feb 9, 2013.

  1. mpilihp

    mpilihp Feeling the Heat

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    Hello I havent been on the forum in a while, I installed a standard water jacket style wood boiler many years and have been keeping warm with it and loving not hearing the oil boiler kick on. But we burn a lot of wood and generate a lot of creatote, like 10 cords a year.

    So im looking to upgrade to a gassifier but without storage, I just dont have space to install that. I see a used Greenwood 100 for sale and looking for owners of these that use them without storage and what sucess you have with it and how ou like it.

    Id also be interested to hear what style gassifier works best without storage.

    Thanks

    ~ Phil

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  2. Downeast Farmer

    Downeast Farmer New Member

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    Hey, Phil--
    I think I've been seeing the same ads you've been looking at. As I've read about the Greenwood boilers on this forum--there are several threads--I've come to think I would have to be a particularly energetic and imaginative mechanical engineer to operate one for a long time. I admire those guys who do, but in the same way I admire pro ball players, with the recognition I'm not in their league. For what it's worth....
  3. mpilihp

    mpilihp Feeling the Heat

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    Hi so do you have a boiler or are you shopping? Yeah the more I read about them the more I am thinking they would be more problem mattic. I have also heard of one called a Greenfire, I think they were build in Houlton ME, they have a bypass flue at the top to prevent smoking. I dont know if they are built anymore, have you heard of them?

    ~ Phil

  4. Downeast Farmer

    Downeast Farmer New Member

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    I haven't heard about the Greenfire. I used a Memco water jacket boiler for twenty plus years and now use a Newmac forced air furnace. I suppose I'm shopping, but what I'm really doing in getting ready to shop. I have this steep learning curve before me on hydronic system design (a path along which I've just taken the first few tentative steps), part of which concerns BTU generation (a gassifier with storage, but whether with integral or remote storage and pressurized or unpressurized storage I'm still trying to work out) and the other distribution, about which there are many questions I'm still way too ignorant to answer (or in some cases formulate). My goal is to have a warm house next winter and to sleep through the night on all but the coldest days.

    Tom at americansolartechnics.com in Searsport can make storage that will fit most anywhere, so you may want to give the storage issue more thought.
  5. Jesse-M

    Jesse-M Member

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    I run a Seton clone ( virtually the same as Greenwood ) without storage, and love it. Simple design with a small learning curve.
  6. 2.beans

    2.beans Minister of Fire

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    if its sized correctly and you can minimize idle times you can run without storage. i ran mine that way at first then added storage later. i like it better with storage.
  7. mpilihp

    mpilihp Feeling the Heat

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    Hi so what make is it? DO you have issues with creosote buildup as greenwood owners have been saying in threads here? Thanks

    ~ Phil
  8. mpilihp

    mpilihp Feeling the Heat

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    Hi thanks for the lead, we have a small basement and really dont want to give up any more space for storage. Plus the cost of it would make a new system expensive. I think sized correctly it can be done. Good luck on your search.

    ~ Phil
  9. Jesse-M

    Jesse-M Member

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    I made it myself, modeled it after a Seton. The biggest problem you have with a unit like this without storage is the shoulder season. You cant let these idle all day or you will have creosote problems.I have been able to manage this pretty well with amount of wood loaded, and water temp. settings. Is it ideal.....no, but very doable..Most times in spring and fall I will only burn at night. During the cold stuff I let her rip...... perpetual fire......::-)
    The biggest and best change i made to the unit itself is to eliminate the exposed insulation inside..........and make easy to use access panels for cleaning the pressure vessel.

    Couple shots of the interior skin to separate the insulation from the combustion area.....

    [​IMG]
    [​IMG]
    [​IMG]
  10. Downeast Farmer

    Downeast Farmer New Member

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    Jesse-M: You run this as shown in the pictures? How hot does the top get? What clearance do you need for the back? Nice work!
  11. mpilihp

    mpilihp Feeling the Heat

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    Hi Jesse wow thats an impressive task built it yourself. So are you saying the pipes have the system water in them and the exhaust gasses from the gassification chamber move up past the pipes to transfer the heat? And if its idling this causes creosote to build up on the pipes? Ive seen setups that for loading it has a bypass flue to allow the chamber with the wood in it to vent out to the chimmny directly and bypass the secondary chamber. Would it be possible to set it up when the boiler is idling to have the vlue bypass open and let it run as a convential fire till heating is needed??

    Do any systems do this to help prevent creosote?

    ~ Phil

  12. Jesse-M

    Jesse-M Member

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    This is how I did the top inner skin and insulation.......it doesn't get very hot at all, the HX takes all the heat.....
    [​IMG]
    [​IMG]
  13. Jesse-M

    Jesse-M Member

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    Yes water is in the tubes....... This is down draft,which doesn't help anything in an idle situation. A bypass flue is a neat idea but have never seen one.
  14. Jesse-M

    Jesse-M Member

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    ImageUploadedByTapatalk1360584579.424622.jpg
  15. avc8130

    avc8130 Minister of Fire

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    From what I see with my WG firebox, those tubes must be COVERED in creosote. You must fight constantly trying to keep them clean for max heat transfer.

    ac
  16. Pat53

    Pat53 Minister of Fire

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    Great Job. That is why I modified my heat exchanger in mine. The tubes were basically laying right against the kaowool on the top and back vertical sections of the HX. The first time I went to clean it the back section tubes were virtually glued to the kaowool. Had to replace the whole back section, so I'm sure there was very little heat transfer there. I moved the HX down and forward about 1.5" so the tubes are more in the flame path and are not close to the kaowool amymore. Much easier to clean now without ripping the insulation apart.

    I added storage 2 years ago also and that has helped a lot in keeping the tubes cleaner. I still give them a good scraping about the end of January and of course again at the end of the season.

    Pat
  17. Jesse-M

    Jesse-M Member

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    I don't mess with them at all during the season....and to be honest, don't notice any difference between freshly clean or used all winter. Its gets so hot in there, a little build up around the tubes doesn't slow up the heat exchange.

    This is a normal amount of build up for me come spring cleanup........other members with similar boilers have commented in past threads that this is normal for them as well.

    [​IMG]
  18. Pat53

    Pat53 Minister of Fire

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    Mine looks similar , but not quite that gummed up. I made a tool out of aluminum flat stock that I bent into a "J" that I can loop over the tubes to clean/scrape them. It works good for getting the inside edge of the tubes.

    Jesse, what size pipe is that going into the header? Looks like only about 1".

    Pat
  19. tigermaple

    tigermaple Member

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    I love your design Jesse. How much $ would it cost to do that to my gw? Did you ever try refractory over the hex? Does the stainless get red hot?
    I have still never taken the back off my gw100 in seven years.
  20. Jesse-M

    Jesse-M Member

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    I also have an aluminum j hook.....lol..........and yes it is 1"
  21. Jesse-M

    Jesse-M Member

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    I have no idea what it would cost, I stole the pieces from my old man....ha
    I don't believe refractory over the HX would be of any help.....the pressure vessel soaks up all the heat before it gets to the top....
    The inner panels I made are 14 GA cold rolled......I cant say if they get red or not because they are hidden, but two seasons now and they don't show any signs of worpage or disfigure.
    I did build some space shuttle type shields for the top out of asbestos siding panels, but I don't think I really needed them.
    [​IMG]
  22. Jesse-M

    Jesse-M Member

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    7 years.......I think I would put that on my spring to do list..........:mad:
  23. Pat53

    Pat53 Minister of Fire

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    I'd be afraid to look !!? LOL
  24. reddtekk

    reddtekk New Member

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    Hi everyone,

    Jesse - VERY nice work. You have the wheels in my head turning.

    I just bought a Greenwood 100. Like Jesse, I've been managing off-season heating by burning only once a day at night (as well as accustoming the family to bathing at night - easier to manage and reduced frequency of laundering bedsheets) and limiting fuel to what is needed. I did notice the insulation leaning on the HX but was not too concerned - someone did bring up a valid point with regards to cleaning though. A close friend of mine has had a Seton 180 clone for 8 years now and he has learned much about this combustion system. I feel that it is worth mentioning a few things here as many in this group may benefit form our combined experiences.

    1. Leave ash in the boiler. You should have a 1-2" layer of ash on the bottom. Aside from protecting the bottom refractory from impact during loading, it has other uses off-season which I will bring up shortly.
    2. Turn off your air door when you are going to leave the boiler idle for long periods. I'm idling for 20-22 hours a day right now. You don't want that air door opening with no fuel - your HX works both ways and you'll quickly cool your refractory as well if you let all that heat up the exhaust stack.
    3. Load only the fuel that you can use immediately. These are not very hard to relight, especially if you have a torch nearby. They will hold embers for a long time too, so you may not need to relight! Ultimately, you want to be able to get to the point where you have little or no yellow flames emanating from your fuel before shutting your air supply off. Basically this signifies that the vast majority of the tars and volatile materials have been extracted from the wood and all you have left is carbon and ash. At this point, you will generate VERY LITTLE (if any) creosote if you were to shut the boiler down for a day. This is where the benefits of storage come in: if you have a place to put all that heat, then you can run a few loads of wood through the boiler before needing to shut it down. These units LOVE sustained burns of at least 4 hours. In my case, I've yet to set up my thermal storage so I must resort to small fires. I've included my cast-iron oil boiler in the loop to add SOME thermal mass, but once a good draft is established this boiler will heat that thing up from room temperature to near boiling in 20 minutes if nobody draws any hot water. It's better than nothing though.
    4. Control your demand (as stated above) if possible and shut down by burying the fire. Once you have all passed through the shower and you have done heating if necessary, move all of your embers towards the door and then bury them in ash. Then disable the air door from opening. When you need it again, unearth the buried embers. Even if they aren't still burning, they light almost instantly. I could reliably idle mine for 22 - 26 hours without need to relight right up until the night time temperature got up to about 45° f. Much above that and I don't have enough draft to keep air moving over the embers through the air leaks in the boiler.
    5. Seal up air leaks and add a controlled minimum air setting to the air door. This will prevent air from bypassing the combustion and cooling the HX and refractory without benefiting you. You need some small amount of air directed at the buried embers to keep them going, but not much. I have not done this on my boiler yet, but my friend has benefited from doing this on his Seton.

    These are great boilers - simple in design and quite efficient. You just need to observe it in operation and learn from it. Everyone's situation will be different - different heat demands, different draft situations, different fuel, etc. but all in all you should like it if you're interested in putting the effort into it. If you are buying cut/split/seasoned wood and you don't want to put in heat storage or spend time babysitting the boiler, save yourself some aggravation and cough up some extra money to get a wood gun and you'll be set. They are picky about moisture content but they work well for on-demand use and shorter burn times and are worth the extra money for someone without a lot of space and time to dedicate to their heating system. If you want fuel flexibility and can be a little more devoted to the system, hands down go for this type of boiler. You can mix green pine in there when it's good and hot and it'll turn it into heat and ash while keeping creosote to a minimum.

    Just as a side note for those on the fence about thermal storage - installing thermal storage not only benefits your wood heat system, it also opens the door to solar possibilities. Installing a thermal solar system is so much easier when you already have a thermal battery. The panels aren't very expensive (dirt cheap compared to photovoltaic) and you will find that the system would pay itself off very quickly when compared to other solar energy harvesting methods. Wood heat is solar heating in a way, but there are a lot of things in the way of the heat reaching your home (tree growing, getting cut down, moving wood to storage, splitting, seasoning, loading into boiler, etc.) So many people neglect to replant when harvesting as well, which makes it an unsustainable process. With thermal solar, heat just goes right from the sun to your thermal system automatically, so you can spend your time (and money if you pay for your wood) doing other things.
    GENECOP likes this.

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