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Realized Benefits of Storage

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by phantomblack, Jan 3, 2014.

  1. phantomblack

    phantomblack New Member

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    Hello all, I have been a long time reader of the site but have never came "out of the closet" until now. I read on this site about folks using 500, or 1000, or sometimes more of "storage" for their heating systems. I am curious what kind of realized effiecncy savings "wood consumption" you have actually seen with these systems. I am curious to understand what quantity of wood you were burning in an average winter before the addition of storage, or how the addition of additional storage into your systems improved your efficency. I understand the reasons that you choose to do storage, with single extended burns but want to know how much you have actually saved in consumption.

    I have been heating my home for the last 4 seasons with a Central Boiler 5036. I see on here that many of you folks favor gassers and I appreciate that. For my situation the boiler that I have fits my needs perfectly. It keeps my 2300 SQ. FT house 74 degrees with infloor heat on about 8 cords of mixed wood a year. I generally run lesser quality wood in low heat demand times (pine, basswood, box elder) and the good stuff when it is needed (ash, hard maple, hickory, elm).

    Fill me in, I'm listening.

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  2. leon

    leon Member

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    The basic fact that screams storage is the greatest idea since sliced bread
    is that you are simply creating more THERMAL MASS to heat your home..

    in my case I used dull fire brick to fill half of my 32 year old boiler with firebrick to create more thermal mas because the boiler only has 25 gallons of water.

    it keeps the fire hotter and there is less much smoke.

    This heated water requires less time to reheat and longer to shed heat for the user because
    the heat is already in the water to use and it takes less energy to heat the water back up to
    high limit temperature.

    If I had the money I would simply buy a used bulk milk trailer tanker that is for
    sale and I would have 3-4000 gallons of potential thermal mass to use to heat my home.

    Buying a used a bulk milk tanker averages about a dollar per gallon, you could sell all the
    pieces parts you will not uses after you get it home and in position for scrap.




    The plumbing would be easy the as the existing fittings are stainless steel and the connections
    would be easy to plumb by making it a non pressurised system.

    The tank would be easy to clean as most of them have internal spray balls or did anyway.
    Last edited: Jan 5, 2014
  3. Donl

    Donl Feeling the Heat

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    The benefit of storage is to help maintain clean burns and provide added convenience to the user. Don't expect savings in wood consumption though.
    flyingcow likes this.
  4. BoilerMan

    BoilerMan Minister of Fire

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    The only savings in wood use are realized by non-existent smoldering. Wood is burned most efficiently in any boiler by keeping the fire hot, air/fuel mixture correct (carburation), and efficient extraction of that heat to useful energy. The only way all three of these things can happen with any current tech is by flat out burning with correct a/f ratio, which results in a very clean flue gas, which enables the use of efficient (large surface area) heat exchange.

    With a boiler, this now huge release of thermal energy (heat) can now be stored to avoid that characteristic run-around-in-your-shorts one minute and freeze 10 hours later effect. STORE the heat and sip on it for as long as it will last then recharge.

    If your boiler does not cycle, does not smoke, and has great heat exchange from the fire, well then you are on top of the game.

    FWIW if I had to burn 8 cord of wood, I'd not be quite so enthousiastic about wood burning, that sounds like a lot of work. I'm less than 1/2 that heating 3,200 square feet.

    TS
  5. phantomblack

    phantomblack New Member

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    Boiler man, you say that you are burning 4ish cord per year and live in Maine? What temp do you heat your home to, and what species of wood do you use most of them time?
  6. jebatty

    jebatty Minister of Fire

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    Ditto BoilerMan comments. Maximum burn efficiency is what storage allows. Plus, storage absorbs the extra efficient heat produced by the burn which is not immediately needed by the space being heated and then can later release that heat to the heated space when it is needed without again firing the boiler. Win - win.

    For me and my shop, the wood is pine and some aspen, and the up to about 140,000 Btuh output of the Tarm during a 6 hour burn heats the shop during the burn, typical winter heat load of about 15,000 btuh, and the extra btu's produced during the burn at a rate of up to about an additional 125,000 btu's go to storage to provide the heat needed for the next two days (burn every other day) until another burn is needed. The Tarm never slows down or shuts down until all wood is fully burned. A six hour burn of pine produces about 1 cup of ash residue.
    BoilerMan likes this.
  7. Fred61

    Fred61 Minister of Fire

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    Idling for long periods or several short periods of idling produces what I call "waste heat". The fuel smolders away and depletes itself producing heat that is too low in temperature to contribute to the heating load.
  8. maple1

    maple1 Minister of Fire

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    I think there is gain but don't think I've read of it being measured.

    Storage reduces the number of burning cycles. Each burning cycle realizes some lost heat in bringing the boiler up to temp, and again at end of burn as its cooling off in some heat up the chimney. So each cycle avoided and extending the cold periods as long as you can represents a gain. That is on top of avoiding periods of idling - any time a boiler sits up to temp with a fire in it, it is wasting wood & making creosote. Smoldering is an awful waste of wood BTUs.

    Unless an OWB can sit there & go cold for a period of time after the fire goes out while storage satisfies loads, I don't see any gains to be had from adding storage to an OWB - don't they need to be kept hot all winter? Unless you can time things with right sized loadings so that it burns wide open until the fire goes out, charging storage (and satisfying loads) while it burns, then by the time storage is depleted you build another fire before the boiler goes completely cold. i.e. avoiding any & all idling. That would also depend on the efficiency of the heat transfer portion of the OWB - some aren't very good at all, just as in the case of some non-gassing IWBs.
  9. Donl

    Donl Feeling the Heat

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    For those of you that find having storage reduces the amount of fuel burned, percentage wise, how much do you estimate you are saving? This is my sixth year with my EKO 40. Two years without and four years with storage. Generally each of those years I have burned about the same amount. A bit less in warmer winters and a bit more in colder years. My boiler is located in a well insulated small stand alone out building where I can't make use of the residual heat produced there. Maybe that is the difference.
  10. peakbagger

    peakbagger Minister of Fire

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    Storage allows me to put the heat where I want it when I want it. With my new mini split supplying heat to the main part of the house (over 10 degrees F). I really only need to heat my home office which is a second floor and there is insualtion between the first and second floor. I heat up the storage in the evening in my basement and the heat radiating from the boiler and flue pipe heats up the 1st floor when the outdoor temps drop in the evening. Then during the day I run the office off storage. I aso can use the boiler more in the shoulder seasons as previously by the time I got it warmed up, the house was warm and most likely overheated. With storage I can use my thermostats so very rarely do I get overheating.

    I wish I had more storage as switching to radiant just isnt in the cards with free heat from my heat pump (due to solar generation).

    As for realized benefits, since I put my storage on line, I have not filled my oil tanks for two years and they are still half full. I do burn more wood but far less than a thought. Previously I was burning about 300 gallons a year.
  11. BoilerMan

    BoilerMan Minister of Fire

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    I burn whatever is available. This year I've got about 1.5 cord of maple, 1 cord birch (mixed white/yellow) and the rest is Aspen (quacking and White Poplar).

    I must confess I have a very tight house which I built, 2200 sq.ft. living space heated to 70+ and 1000 sq.ft. boiler room and shop (all attached) heated to around 65 average. The shop has two 9x7 insulated overhead doors. All on a 8" thick heated slab on grade, upstairs heated with restored CI radiators. Domestic water heated via 115gal indirect. House is 100% wood heated all the time.

    TS
    Last edited: Jan 4, 2014
  12. maple1

    maple1 Minister of Fire

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    I don't think I could hazard a guess. It might turn out to be a minimal amount. But I feel I could make further savings if I had more storage than I do, mainly from being able to skip more days burning during shoulder season. 660 gallons isn't really a lot - I think I could save at least a month of burning days (30 burns) in the course of a year if I had 1000. More like 60 burns, likely. Not sure how that would translate to savings, since the burns would be a bit longer, but lighting 60 less fires is appealing.
  13. phantomblack

    phantomblack New Member

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    My OWB holds 200 ish gallons of water all on its own, I was just trying to figure out if any fuel could be saved with my existing setup if I were to have storage. Sounds like the answer is no.

    I do not have a problem with our current wood useage, as prior to my complete conversion to wood heat I was using 1200 to 1500 gallons of propane a year. Thanks for the feedback folks.

    Plus, who can put a price on having your wife run around the house with a tank top and shorts on, even in winter? Worth the cutting to me! Maybe the old saying wood warms twice is wrong, maybe it is three times ;)
  14. BoilerMan

    BoilerMan Minister of Fire

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    Someone on here used to have a saying in their signature that I've quoted to friends and co-workers who don't believe in wood-heat.

    "If your wife still has all her clothes on, it's time for another log on the fire"

    TS
  15. Fred61

    Fred61 Minister of Fire

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    Remember we like photos on this forum.
  16. hobbyheater

    hobbyheater Minister of Fire

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    In the early 80s storage was added to a non-gasification boiler with the hopes of reducing creosote buildup. Creosote got worse because I had no idea of the need for return water temperature protection. The big surprise was the reduction of wood consumption of 40%!
  17. mr.fixit

    mr.fixit Member

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    Phantom,just for comparison,I heat around 4000 sq. ft. in 3 buildings(4 if you count the building the boiler is in) on 9 to 11 cords.(depending on the winter)
  18. mmudd

    mmudd Member

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    Storage has cut down on fire frequency and appears to save wood for me? My non gasser holds only 35 gallons water. Previous to 500 gal pressurized storage, with fire out = no heat, so we always kept a fire going or house temps dropped. Now I fire once a day in normal Missouri winter. (High 35-40, low 20F) Since Sunday, temps have been below/near zero ,and it takes two fires a day in these conditions, but the biggest benefit is that house temps remains constant. No more cold mornings, and usually don't have to fire boiler before leaving for work. This morning house was still 70 , outside temp was -10F, fire was out, but storage temp was near 130, still putting out some heat. It really helps to keep house temp constant, so you are not having to catch up, which = more wood

    Looks like I'll use about ~7 chords to heat 3000 sq ft. I added some wall radiant which made a huge differerence in how often the heat sucking fan coils needs to run, which really helped stretch out storage. I plan to add more to get way from using fan coil as much as possible. I can run storage temps much lower with radiant as it can used mixed down temp water
  19. TimfromPittsburgh

    TimfromPittsburgh Member

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    After 15 years of running the Tarm 502 with no heat storage, I have added 450 gallon of non-pressurized storage two months ago. Its too soon to tell if my wood consumption will be lower but I can absolutely say that creosote and tar accumulation in the boiler firebox and fire tubes is dramatically reduced. I think I am burning a little less oil as the stored heat supplies the heat demand on a typical winter night.
  20. NE WOOD BURNER

    NE WOOD BURNER Minister of Fire

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    I would imagine a nice boiler building built around your OWB and thermal storage would be similar to a non gasser boiler hooked to storage.

    build it to fit a Garn when you replace your OWB down the road.

    I know a few that have built simple shelters to help with the stand by loss of OWB.
  21. Paso

    Paso Member

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    This is a very informative post for someone starting out, deciding whether to add storage to the mix or not.
    I was one that "thought" that the storage would reduce wood consumption. Boy was I wrong I burnt more wood trying to keep the storage temperature up to what I was reading others were keeping theirs at. Then I realized we all have different burning situations. I was living in an area where we get -40 for weeks on end. Good post Phantom black :)
  22. 91LMS

    91LMS Member

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    i am only 2 weeks into operating with my storage. temps have been unseasonably cold. seems like i cant put enough wood in it however its charging the tank when i am there to burn and sipping off the tank when i am not. no replacement for that, i simply cant keep a fire going when i am not home so i previously was committed to switching to that dreaded oil 50 % of the day . its not perfect on my part not running a gasser and wishing my boiler held more wood... still dreaming of a gasser in my future even if its a used unit. BUT my baseboard bumps along and the radiant zones are satisfied until i can refire and play catch up.
  23. phantomblack

    phantomblack New Member

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    Seems to me after reading a fair amount of posts that storage is a good idea if you are living an a somewhat temperate environment, or on low demand heating days when you are using it in conjunction with a smaller gasser indoors.

    A coworker has an OWB that is a gasser (natures comfort). It is a nice running unit, and does not require a lot of "fiddling" to keep it running. When the unit that I have decides to go to the scrap yard ( I hope that is a long time from now) I will probably convert to an OWB gasser.

    I like the idea of the large firebox, and being able to load 150 lbs of wood and not have to worry about the system keeping up, or having to burn propane to keep up. I appreciate all of your guys feedback, but with my current setup I just do not think that there is a benefit for me.

    Here is a pic of my current boiler and woodshed.

    Attached Files:

  24. kopeck

    kopeck Minister of Fire

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    I don't think that's the case at all. Properly sized storage may not save you a ton of wood but it will save you a ton of time, no matter where you live. The idea that I only visit my boiler twice a day to heat my entire house plus DHW is a pretty nice perk. I also don't have to spend as much time cleaning my unit as it burns hot and fast all the time.

    BoilerMan resides in a pretty cold area, I'm probably 4 hours south of him and 5-10 degrees warmer but still see temps in the single digits most nights during the winter. Storage works in all climates.

    K
    Last edited: Jan 8, 2014
    BoilerMan likes this.
  25. maple1

    maple1 Minister of Fire

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    Besides that, I don't have to even look at my boiler in the morning hours, at all, if I don't want to. That is quite appreciated at times, here at least.

    And the larger the boiler the more beneficial it is, as the more idling it will prevent.

    Big boiler + Big storage + Alpha load pump = Easy Heating For Dummies.

    (Self included...)

    ==c
    BoilerMan likes this.

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