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[vinrum]

I have read alot about external water storage once the boiler is up to temperature in the indoor wood boilers.  I was wondering if the concept is the same for outdoor wood boilers?  I realize that the outdoor wood boilers have much more water capacity than a indoor boiler, What I am asking , Is there any benifit to extra water storage, beside the water in the OWB.  Also, could I run lines off the storage tank to another zone (garage)..

Thanks
Steve

[willieG]

steve if  your pump is big enough on your stove you could just make a manifold inside your home with  multiple outlets and make a return manifold the same and add a set of lines to your garage (i think mine has 4 outlets on it now..furnace..domestic hot water..a rad in my old fireplace and my floor heat)
as for your indoor storage tank..i see no harm in that (i am only guessing but i have thought of doing the same thing figuring that if i heated more water the OWB would burn longer  and that would mean less starts and stops which would mean better efficiency due to not losing valuable heat (smoke and gas) up the chimney  when the fire dies down and restarts as we do now.

i actually did this in a small fashion for my garage i wanted the option of heating it only when i wanted to work out there and my garage  is closer to my OWB (which itself is in a small shed) so i built a 50 gallon tank that went on my return line just before the OWB inside this i have a coil and this goes to my garage. I have an expansion tank in the garage  and this line is a closed loop filled with antifreeze solution(of cours i have another pump) now when i want heat i just turn the system on and when i am not there iturn it off the antifreeze leave me worry free about it when it is not running and the OWB works like it is not there anytime(in use or not) it just cools the return water a little more before going back into the stove

[rosewood]

steve, i can speak from first hand results . i have 1200 gals of water storage and have  seen extended cycle times and longer burn times.it is only a benefit to have more water storage. put it this way what holds more temp longer 55 gal or 5 gal ?

[higgins11]

I'm wanting to do something similar.

I have a 8,000 gallon tank with a pressure bladder that I plan on insulating and burying in the ground. I want to use it for potable hot water storage. Would putting a heat exchanger in the tank accomplish the same effect for storage (ie shorten run times, and increase thermal mass for the out door wood furnace?

or would the tank need to be plumbed into the furnace so that it all could circulate........if so i would have to find another storage system for potable water

[Scott7m]

My 5000 sq ft heatmaster mf5000e only holds 130 gallon and it is by far the most efficient stove ive ever used. 

I guess in terms of the water capacity some folks think it won't work, oh well though

[higgins11]

Scott for my application it will not work

I'm putting the 8000 gallon tank below a greenhouse with the idea that the heat from the tank will rise and keep the greenhouse warm. I was also hoping to used the hot water from the tank as potable (not sure that is feasible yet)

The whole idea comes from a passive solar greenhouse design where you store water in barrels inside the greenhouse to minimize temperature swings overnight.

Ideas?

[Scott7m]

I'm full of ideas lol, I'll chime back in when I get more time.  How are you planning to heat this water?

[higgins11]

thats part of my question..........if i keep it all as potable .........then i suppose i'll run a loop from the furnace (out the hot water loop) to a heat exchanger inside the large tank.

if the heat exchanger idea is to much ..........then i'm looking to just run a loop from the furnace ........pumped to the tank and back to the furnace

[jackel440]

I say mass storage is the only way to go.I plan to have about 2k gallons at some point.all super insulated in a building with the boiler.

[Scott7m]

I say mass storage is the only way to go.I plan to have about 2k gallons at some point.all super insulated in a building with the boiler.

Jackal the cheapest and easiest ways stud up a wall around your tank and go rent the blow in machine from lows and surround it with a couple feet of insulation, it's great

[martyinmi]

I guess I don't understand the appeal of mass storage. Today's modern OWB gasifiers start burning smoke almost instantly, are insulated very well, and only need to be filled once or twice a day. The insulated pex is way better than it was even 5 or 6 years ago, so there is very little thermal loss there. I'm just not hip on starting a new fire once a day, or every other day, or what ever the case might be. I've read on other sites where people end up being slaves to their systems(that's my term-not theirs)- in that they may be up at 2 am on a Sunday building a fire because their storage tank is under the temperature necessary to maintain a minimum temperature in their house.
   I think it was a brilliant idea before the advent of OWB gasifiers and I understood the logic behind the concept, but now that the OWB's technology has caught up with the Garns and their other European counterparts, it just doesn't make sense to me. It has to be nearly as efficient, if not more efficient, to just feed the gasser in the back yard once or twice a day. OWB gassers most certainly gives us a reliable routine to follow, without the uncertain variables involved with mass storage.
   I believe that if mass hot water storage were more efficient or practical, you'd see propane, natural gas, fuel oil, or even electric set-ups that incorporate it. Maybe they are out there? Guess I've never heard of or came across one.   

[higgins11]

My philosophy (right or wrong) leads back to theories of passive heating a greenhouse.............to stabilize temperatures at night you add water that is heated by the sun during the day and released at night. The more volume of water the more stable your temps are

@martyinmi
shouldn't you be able to keep a small fire burning constantly so the storage water does not drop to low? feed small amounts of wood 2 times per day or large roaring fires every other day.........i would choose to maintain a small fire daily so you don't work the system hard every other day

I don't have a modern gasifier........i have an older taylor.....I would assume you wouldn't want to mess with newer gassifiers as much

[Scott7m]

Old designs like Taylor really are different animals than what we have today.  I agree with Marty, butflr those who want water storage go for it.

The bottom line is that it still requires the same amount of btu to heat the space you want to heat.  The gassifiers of today instantly start Gasifying and not wasting any wood. 

So in regards to the heating of the space, the modern gasser would do it on half the wood of the Taylor without a storage tank. 

[martyinmi]

My philosophy (right or wrong) leads back to theories of passive heating a greenhouse.............to stabilize temperatures at night you add water that is heated by the sun during the day and released at night. The more volume of water the more stable your temps are

@martyinmi
shouldn't you be able to keep a small fire burning constantly so the storage water does not drop to low? feed small amounts of wood 2 times per day or large roaring fires every other day.........i would choose to maintain a small fire daily so you don't work the system hard every other day

I don't have a modern gasifier........i have an older taylor.....I would assume you wouldn't want to mess with newer gassifiers as much

Small fires are extremely inefficient. If they are not hot enough to burn smoke, then you are blowing around 45% of your potential energy out your stack. Roaring fires are efficient as long as you have an effective means to capture the heat. I would not want to go to bed worrying about running out of stored heat and thinking
"maybe I should have built a fire", all the while laying awake wondering if my wife might wake up at 3:30 in the am because she's cold. It sounds like what you have in mind will work for you. I guess I wouldn't ever do it for myself knowing how incredibly simple it is just go throw wood into a machine that is already incredibly efficient and have the hot water pumped through a few water to air heat exchangers with a cheap old furnace blower behind them(I'm referring to a greenhouse set-up).
   Good luck with whatever you do. Remember- my opinions are just that- opinions. If you feel that you have a great idea or a bold new concept, just "git 'er done". I am truly amazed at what some of the guys do on this site. In your case, necessity will really be the mother of your invention.

[jackel440]

I agree the most efficient burn is when the stove is running full out.Now that being said I feel that if my gasifier is running full throttle I can use that burn cycle to heat my water storage up to my 180* set point.Then shut the boiler down and live off the heat from the mass storage for several days.Then re light and Burn a nice long clean burn to bring back up to heat the storage tank.
I can then also go away for the weekend ,and not be dependent of someone to come throw wood n the stove.Just like when I go to work and don't get home till 16 hrs later.I know that i dont have to worry about the temp being down in the boiler,and then having to get it back up before i go to bed.
I can see a great savings in wood being burnt.
Instead of a constant fire 24/7 I could burn perhaps 8 to 12/hours full bore and be burning clean.
Now this is just my guess for my situation.I feel this is what will work best for me.
Now I just need to find a couple of tanks