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how much more efficient is a lambda boiler when run w/o storage?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by tjvt, May 27, 2014.

  1. tjvt

    tjvt New Member

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    I've heard everywhere from 5-25%. What has been your experience?

    I'll be running w/o storage for the foreseeable future. How much less wood can I expect to burn with a lambda unit vs. a non-lambda unit, all other things being equal.
    Last edited: Jun 2, 2014

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  2. sinnian

    sinnian Minister of Fire

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    Than what?
  3. tjvt

    tjvt New Member

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    Than a comparable boiler w/o lambda. For instance, I'm considering a Solo Plus 40 and a Vigas 40. A more accurate comparison would be the same boiler with and w/o lambda. Not sure who makes the same model with and w/o lambda, but I'm pretty sure some manufacturers do. I assume the truth is somewhere in the middle of the 5-25%, but if it's going to save me 2-3 cords a year that may tip the scales.
  4. maple1

    maple1 Minister of Fire

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    I can't say from experience or have any kind of data - but I suspect it would be the lower end of that scale.

    I would also suspect it would depend somewhat on wood quality & operating procedures, as I think Lambda controls would have some ability to compensate or adjust to wood & procedures that weren't optimum.

    (In other words, could compensate somewhat for a lazy owner - but not to imply by any means that Lambda owners are lazy, of course.)

    Would be interested in seeing some data on it though.
  5. ewdudley

    ewdudley Minister of Fire

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    Sounds about right. A conventional downdraft gasifying boiler can be expected to achieve 80% efficiency, so getting up to 105% just by adding lambda controls should be no problem.

    If you burn four cords a year with a conventional gasser then you would expect to burn no more than three cords with a lambda gasser, which would pay for the lambda in no more than three years in most cases.
  6. Karl_northwind

    Karl_northwind Burning Hunk

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    What I heard from a manufacturer in Sweden (effecta) who makes an identical boiler in a lambda and non-lambda (only the lambda is available in the US) the difference is nearly nil in the lab, (perfectly consistently dry, perfectly consistently split wood) and 10-15% in the "field", IE, the same boiler, same setup, same load but with different wood load, varying size wood, different moisture content, etc.

    for what it's worth...
    karl
  7. skfire

    skfire Feeling the Heat

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    105%?????.....unacceptable....mine cruises at 156.7892%....with a load of freshly cut cottonwood......

    sorry feeling pesky....on the tarmac in Philly on the way to Greece.....yeeeeha....boiler off....I am out....
    Scott
    Chris Hoskin likes this.
  8. TCaldwell

    TCaldwell Minister of Fire

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    In my opinion dry wood is more important than o2 control if given the choice. O2 will optimize a batch burn for a longer time period, through regulating p/s air dampers creating a more consistent burn. With today's boiler combustor designs being as good as they are, with a properly set up non lambda and good wood the difference can be small. This difference is made even smaller by the small outputs of residential boilers. With that being said, dry wood and o2 is still my choice!
  9. woodsmaster

    woodsmaster Minister of Fire

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    I don't have a lambada, but the only place I see it having much advantage is at the beginning of the burn. It will give more oxygen to get the fire going faster. I manually lambada mine for a minute or two at start up by cracking the upper door until my flue gas gets over 300.F
  10. tom in maine

    tom in maine Minister of Fire

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    I Lambada, too!
  11. Fred61

    Fred61 Minister of Fire

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    Funny, that doesn't look like you. Must have been when you were younger;lol
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  12. woodsmaster

    woodsmaster Minister of Fire

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    I'd do the lambada with her.
  13. flyingcow

    flyingcow Minister of Fire

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    My thoughts. Like everyone else, not sure how much of a savings, but looks like Karl has some good info. The Euro's know their stuff.

    If you have varied species of wood in your pile, it'll help. I think they shut down a bit earlier and save a few coals to help restart. My Innova is pretty much fine ash when it's all done. But I can start a fire pretty quick.

    If i was to do it over, I'd buy a Lambda unit. Actually if i was to do it over, I'd have a pellet boiler. :)
    sloeffle likes this.
  14. TCaldwell

    TCaldwell Minister of Fire

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    woodmaster, most lambda controlled boilers are started open loop { sensor over ridden} until the flue temp reaches x or a determined ammt of time has elapsed. The measured o2 before 1200degf is reached is not accurate, as you know wood is finicky but relatively predictable. Most p/s damper staging at the beginning of a burn is designed to slowly bring the fire to o2 setpoint at 1200degf + before closed loop o2 control. This is important for a batch burn, started this way the secondary burn temp will stay steady or slowly climb as long as there is enough wood. If the starting air staging is not done properly the dampers will have to make extreme manipulations that really disrupt the combustion chemistry process, and effiency. I have tried many combinations of starting damper positions and have found 50% primary and 50% secondary to be good with my modified garn open loop until my 02 reaches 5% [ the secondary burn temp will between 1200-1500deg], then I switch to closed loop control, My o2 setpoint is 4%.
  15. Mike Fromme

    Mike Fromme New Member

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    I don't have any visible smoke coming out the chimney 10 minutes after I start my non lambda boiler. Good enough for me.
  16. Vizsla

    Vizsla New Member

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    Its hard to say exactly, and I would never use lab data to compare. Lambda is gonna adjust constantly for every second of the burn, adjust to each different specie and how it burns and the changes from day to day thru out the season. It seems a non lambda would need constant monitoring to do the same. So it almost sounds like a convenience as being the biggest benefit. A rough guess would be 5-10 percent comparing very similar models in the field burning. I would think the start and end of each cycle is where the biggest gains are.
  17. heaterman

    heaterman Minister of Fire

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    It would depend a lot on how the non lambda unit was operated. If for instance you compared a lambda boiler to a batch burn like a Garn or say an EKO 40 with 1000 gallons of storage, the real world reduction in wood use would be negligible. A good batch burn system is going to hit 80%+ pretty easily if you have properly seasoned wood.

    If you compare a lambda vs non lambda in an on/idle/off application (no storage) the difference is going to be more substantial. Over the course of an entire load of fuel, probably in the 15-20% range.

    Thermal storage will do you far more good than lambda all things considered.

    An excellent example is Tom's Garn which he mentioned a couple posts above here. He took a standard Garn which already ran in the 82% range and did a superb job of modifying the thing to use independently operated primary and secondary air inlets. All computer controlled and very sophisticated. I think I remember him telling me that he gained about 3-4% efficiency.
  18. Mike Fromme

    Mike Fromme New Member

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    Any data to back that up or we talking internet math here?
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  19. TCaldwell

    TCaldwell Minister of Fire

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    I think the beginning of a burn is a toss up, depends on what your p/s damper positions are with regards to wood mc. The middle will maintain setpoint, conserving wood, the end is where o2 control will have a real benefit. If your static p/s air distribution is still at 50% for example, the end will take forever, as you wont get the heat out of the char stage. With o2 control at that point the bulk of the air is through the primary damper and blasting coals creating the hottest part of the burn with minimal heat up the stack. This is more evident on a total batch burn to exhaustion with storage. Alot depends on the boiler combustor and hx ability. A garn will run at o%o2 about 10 minutes after startup very comfortably for about 15 minutes with very high secondary burn temps cleanly due to the combustor design and transfer massive btus into a relatively cool boiler by design. Other designs might have more difficulty, so o2 control is just a way manage the burn, taking the high and low volatility and smoothing its behavior to maintain a o2 setpoint that is compatible with the combustor design to maintain steady effiency. As stated earlier with todays advanced boiler designs, the difference with good wood is marginal.
    flyingcow likes this.
  20. Karl_northwind

    Karl_northwind Burning Hunk

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    My guess is that on startup in any true batch burn device, an extremely low secondary chamber mass (GARN or effecta) will have minimal startup emissions. the more mass in the secondary area, the more emissions till the mass comes up to temp. All effecta burners are batch, full storage only, no cycling, so any measured gains there would not be due to cycling efficiency.
  21. tjvt

    tjvt New Member

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    I will be running w/o storage for the foreseeable future. If I am likely to cut my wood consumption by 15-20% with a lambda unit, that's huge.
    flyingcow likes this.
  22. heaterman

    heaterman Minister of Fire

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    I wouldn't take that to the bank. Far too many variables in play to count on an exact number.
    Karl brings up a very salient point with the mass in the secondary chamber. It can make a huge difference in the amount of time needed to get the secondary chamber up to temp.
    It coincides with what Tom is saying about the flue gas having to reach a certain temp or a set amount of time being reached before the control even starts to regulate what is going on.

    In other words, even if you have a lambda controlled boiler, you may seldom reap any benefit from it if the boiler is experiences a lot of short cycling.

    Even the EPA is wising up to this (and that is saying something!) from what I can see of their new proposal. Basically, you will have to have storage to reach emissions levels with any gasifier, lambda or not.
    Seriously, storage is the answer to a greater degree than lambda, at least in my humble opinion.
  23. hobbyheater

    hobbyheater Minister of Fire

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    This clean efficient burn would not be possible without storage. The boiler at the bottom of this chimney is a 32 year old Jetstream boiler - one of the first gasification boilers. The non-gasification boiler before the Jetstream saw a 40% drop in wood consumption with the addition of storage!
    BoilerMan likes this.
  24. maple1

    maple1 Minister of Fire

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    Based on Tcaldwells input above - I would not count on that. I think he observed maximum Lambda benefit on the latter stage of the burn, and with a cycling boiler I don't think you would get to that stage as often. And, the lambda circuit is bypassed in the very early burn stage - which would be happening a lot more with cycling.

    But I have no lambda experience, so I could be wrong. :)
  25. BoilerMan

    BoilerMan Minister of Fire

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    More proof that storage actually saves wood...........

    Well it allows the equipment to run more efficiently which saves the wood.

    TS

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