Does "shoulder" wood matter with a gasser and storage?

[JP11]

I get the physics behind it. With "shoulder" wood.. You would be pissed if you paid for X cords and got all hemlock. Less BTU's per volume.

Same idea with burning it. Firebox is only X big... you can't fit as many BTUs in one loading as you can if it were something more dense.

BUT.. if those of us that have boilers with storage burn it. What's the downside? Just more loading is all I can figure. We aren't attempting to get a longer burn time because of storage.

The only goal is to keep the flue temps down, but not make creosote, and make as much of the wood as you can go INTO the tanks, Right?

Wondering if I'm missing anything. I'm ready for winter. Other than a DHW aquastat on my indirect that seems to be sticking. Hot water temp in the house is wandering. I've tried to blow it out with the compressor, and lubed a bit with WD40. No luck so far.

JP

 

[goosegunner]

I feel the same way. This summer I used my lower quality wood to heat the pool. Short cutoffs, crotches and not the top quality pieces. Dry is all that matters. When I heat the pool I am typically around during the process. Boiler with storage is much more user friendly. It just doesn't matter if output declines for a short time the tank will cover it.

Now fast forward to winter, when I head off to work I enter my tank temps on the iPad, it tells me how many lbs of wood to burn to get to desired temp, set the timer and go to work. Having good same quality wood will produce more consistent results.

gg

 

[Jeff S]

JP11you right on target .I burn a lot of the more undesired wood such as Aspen or willow or even punky wood and what I have found is that I get get my storage tanks up to temp in the same time frame as with better quality woods,just need to load more frequently.For example in the middle of winter I burn every other day for 10 - 12 hrs this is is from striking the match until the fire is completely out.,this may require 4-5 loadings of Aspen compared to 3 of Ash.

I don't necessarily look for these types of wood ,but during the process of cleaning out my approximately 6 acres of woods of all dead wood I have a choice of throwing it on the brush pile or using it in the boiler,I choose the latter.

 

[jebatty]

All I burn is aspen and pine, shoulder wood to some, perfect wood for me.

 

[infinitymike]

in the middle of winter I burn every other day for 10 - 12 hrs this is is from striking the match until the fire is completely out.,this may require 4-5 loadings of Aspen compared to 3 of Ash.

WOW 10-12 hours? 3 loads. I dont have storage yet but that sounds like a lot of work. I burned 3-4 loads every 6-8 hours everyday. Burning for 10 hours straight means you got to be around all that time, right?

I thought if I got storage I would only have to load the firebox once a day and it would charge a 1000 gallon tank.

 

[JP11]

Thanks for the thoughts. With my job.. I'm either HOME, or GONE. I leave for 6 or 7 days. My wife works from home. So the difference between a 3 hour burn and a 5 hour burn is insignificant. The Vigas says 4:15 is a normal burn. Of course you can crank it up or down on the controller, so I'm sure that time varies.

 

[jebatty]

For example in the middle of winter I burn every other day for 10 - 12 hrs this is is from striking the match until the fire is completely out ... this may require 4-5 loadings of Aspen compared to 3 of Ash.

WOW 10-12 hours? 3 loads. I dont have storage yet but that sounds like a lot of work. I burned 3-4 loads every 6-8 hours everyday. Burning for 10 hours straight means you got to be around all that time, right?

I thought if I got storage I would only have to load the firebox once a day and it would charge a 1000 gallon tank.

Every other day burn for me also, even down to -35F. My burns are about 6 hours (aspen and pine), and about 3 loadings, every 2 hours or so.

As to loading once a day and charging a 1000 gal storage tank, take time to think this through. How much wood in pounds will your firebox reasonably hold? What is your lbs/hr burn rate? What is the efficiency of your boiler? How many stored btu's do you need for a day's heat; and what is your usable delta-T? What is your hourly heat loss or demand? A 1000 gal tank, from 185F-120F (delta-T=65F) stores 542,000 btu's, if you can use water down to as low as 120F. Assuming this is 100% available with no losses to get those btu's to the heated space, that will provide just about 11 hours of heat with a heat loss of 50,000 btuh. One pound of 20% MC wood and 400F stack temp will provide about 6,000 btu's, which is 90 pounds of wood for 542,000 btu's. Down rate that for your boiler efficiency in transferring btu's to your storage. If your heat loss is higher and/or you need water at a higher temp, adjust the numbers accordingly. Burning wood for hydronic heat is math, not magic.

 

[goosegunner]

WOW 10-12 hours? 3 loads. I dont have storage yet but that sounds like a lot of work. I burned 3-4 loads every 6-8 hours everyday. Burning for 10 hours straight means you got to be around all that time, right?

I thought if I got storage I would only have to load the firebox once a day and it would charge a 1000 gallon tank.

As stated above it is math, and with a little observation it is not to hard to figure out. I ran my Econoburn 200 the first year without storage and added it last year. I can tell you the added convienience is well worth the time and cost to set it up. It eliminates the urgency of, oh crap I better get up in the morning and add wood or I better get home to add wood.

Above 20 degrees I have one fire in the evening, below 20 degrees I have 2 small fires morning and evening. I do that because I have a forced air coil and I like to keep hot water at the top of the tank. My storage would also be short of 24 hours in colder weather so it is a matter of timing. Burn a small load before I head off to work, and then one sometime after supper.
I have mine set up with a timer so the fan shuts the fan off.

gg

 

[JP11]

I like the math. I really think I'm gonna be two small burns a day in winter. I think I need about 800k on an "average" winter day. 2 million on a -10 day. I guess that 800k is one full burn on the vigas. Won't really know till I get doing it I guess.

 

[goosegunner]

I like the math. I really think I'm gonna be two small burns a day in winter. I think I need about 800k on an "average" winter day. 2 million on a -10 day. I guess that 800k is one full burn on the vigas. Won't really know till I get doing it I guess.

I would be surprised if you can get 152 lbs of wood in a single load. You would need high quality wood cut to max length to get 800,000 out of one load. But maybe, time will tell.....

 

[goosegunner]

I would be surprised if you can get 152 lbs of wood in a single load. You would need high quality wood cut to max length to get 800,000 out of one load. But maybe, time will tell.....

I stand corrected, i was thinking the firebox was close to my Econoburn 200 at 8 cubic ft. The vigas 60 has a 11 cubic ft fire box. You should get 152+ lbs in that firebox.

gg

 

[Jeff S]

It all depends on your schedule,I can start a fire after work,add another load in 2-3 hrs then load it up before bed and let it burn out while I'm sleeping.

I could also do 1 or 2 loads and burn every day,but I prefer to skip days.

Also I have the EKO 25 which has a very small fire box,if I had one of the larger units I could get away with less feedings.

 

[goosegunner]

It all depends on your schedule,I can start a fire after work,add another load in 2-3 hrs then load it up before bed and let it burn out while I'm sleeping.

I could also do 1 or 2 loads and burn every day,but I prefer to skip days.

Also I have the EKO 25 which has a very small fire box,if I had one of the larger units I could get away with less feedings.

The key to you skipping days is your cast iron radiators. Forced air coils need hotter water. I can drop to 130 but I usually fire at 140.

gg

 

[infinitymike]

Every other day burn for me also, even down to -35F. My burns are about 6 hours (aspen and pine), and about 3 loadings, every 2 hours or so.

As to loading once a day and charging a 1000 gal storage tank, take time to think this through. How much wood in pounds will your firebox reasonably hold? What is your lbs/hr burn rate? What is the efficiency of your boiler? How many stored btu's do you need for a day's heat; and what is your usable delta-T? What is your hourly heat loss or demand? A 1000 gal tank, from 185F-120F (delta-T=65F) stores 542,000 btu's, if you can use water down to as low as 120F. Assuming this is 100% available with no losses to get those btu's to the heated space, that will provide just about 11 hours of heat with a heat loss of 50,000 btuh. One pound of 20% MC wood and 400F stack temp will provide about 6,000 btu's, which is 90 pounds of wood for 542,000 btu's. Down rate that for your boiler efficiency in transferring btu's to your storage. If your heat loss is higher and/or you need water at a higher temp, adjust the numbers accordingly. Burning wood for hydronic heat is math, not magic.

Thanks Jim,

I never really gave it any real thought just a lot of assumptions based on what I've read here. But You shed some light on the process.

I haven't done a heat loss calc, but don't think I would need as much as you guys based on location alone.
But I have a somewhat poorly insulated 1600 sq ft 1950's house (2500 if you include the basement).

The wood gun only has a 6.5 cubic foot firebox. So do you think I could only get 70-80 pounds of wood in there? I have base board heat so I think I need at least 160* Thats a 1000 gallons at 185*- 160* a delta T of 25 if my math is right thats stores 208460 btu's? With a heat loss of 50,000 thats only gives me 4 hours, ouch. 70 pounds of wood gives me 420,000 btus so I would do half loads every four hours?
I don't know if what I'm typing even makes sense.

I found last year (which was my first and was extremely mild) That I would put a full load in at 5:30 am, my wife would put a load in at 1pm, I would come home at 4pm and put a half load in and then at 10 pm put another half load.
Remember the wood gun doesn't idle, it shuts "off" .

I guess I need more info to figure out how well storage would work for me.

Let me know if I should start a new thread

 

[goosegunner]

Thanks Jim,

I never really gave it any real thought just a lot of assumptions based on what I've read here. But You shed some light on the process.

I haven't done a heat loss calc, but don't think I would need as much as you guys based on location alone.
But I have a somewhat poorly insulated 1600 sq ft 1950's house (2500 if you include the basement).

The wood gun only has a 6.5 cubic foot firebox. So do you think I could only get 70-80 pounds of wood in there? I have base board heat so I think I need at least 160* Thats a 1000 gallons at 185*- 160* a delta T of 25 if my math is right thats stores 208460 btu's? With a heat loss of 50,000 thats only gives me 4 hours, ouch. 70 pounds of wood gives me 420,000 btus so I would do half loads every four hours?
I don't know if what I'm typing even makes sense.

I found last year (which was my first and was extremely mild) That I would put a full load in at 5:30 am, my wife would put a load in at 1pm, I would come home at 4pm and put a half load in and then at 10 pm put another half load.
Remember the wood gun doesn't idle, it shuts "off" .

I guess I need more info to figure out how well storage would work for me.

Let me know if I should start a new thread

Mike,

A few issues here;

Do a heat loss calc before you do any more boiler additions.

If you truly need 160 degree water storage will be of less benefit.

Replacing base board with cast iron rads would be a big advantage for storage.

50,000 btus/ hour would seem like a high loss except at peak lows, average should be lower.

No such thing as a solid fuel appliance that shuts off.

gg

 

[JP11]

Looking at the math..

To do a max "heating time" wouldn't you ADD the storage BTUs and the firebox?

I haven't ever been able to get the boiler really going like that, because I had it up and running late spring. But say it was really cold, My house needs about 100k BTUs/hr

If I went to sleep with charged tanks, AND the boiler going. I have a litter over 600k stored. 195 down to 135. Also the wood is there to be used up that's another 800k or so. That's why I went oversized on the boiler. I can run my storage down, then "catch up" the next day while still providing heat for the house.

Maybe my guess on how it will work is wrong. I'm hoping that it's all sized to work for a nice easy night no matter the temps outside. Of course, I always have the automatic oil backup.. But I'm treating that thing as evil.. and not even putting my biodiesel in it this season (the bio needs to be burned within 6 months due to storage issues)

JP

 

[goosegunner]

Looking at the math..

To do a max "heating time" wouldn't you ADD the storage BTUs and the firebox?

I haven't ever been able to get the boiler really going like that, because I had it up and running late spring. But say it was really cold, My house needs about 100k BTUs/hr

If I went to sleep with charged tanks, AND the boiler going. I have a litter over 600k stored. 195 down to 135. Also the wood is there to be used up that's another 800k or so. That's why I went oversized on the boiler. I can run my storage down, then "catch up" the next day while still providing heat for the house.

Maybe my guess on how it will work is wrong. I'm hoping that it's all sized to work for a nice easy night no matter the temps outside. Of course, I always have the automatic oil backup.. But I'm treating that thing as evil.. and not even putting my biodiesel in it this season (the bio needs to be burned within 6 months due to storage issues)

JP

After using my storage for a year I would say that is not really how you want to run your boiler. Most try to time the burn out with the completion of the charging. If you load full again once you are charged you will make a mess of the boiler as it idles for extended periods.

With experience you can time your burn to be complete some time in the night. My goal is to never idle. It is fairly easy to accomplish with a little observation. I have a spreadsheet on my iPad that does all the math. I enter tank temps, current boiler temp, approximate heat load per hour, projected hours of burn. It tells me how many lbs of wood to burn to get to desired tank temps.


gg

 

[Jeff S]

goosegunner,

Your absolutely right about the cast rads,I heat storage up to 200* but only use an average of 100* in the rads themselves(110* leaving storage 90* returning)