I understand the efficiency of gassifier's. But do to high costs, I wanted to know if anyone has seen regular wood boiler setups with thermal storage? I haven't found any good examples.
Wood Boiler (non gassifier) with thermal storage
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I have an Earth outdoor wood boiler. It has 315 gallon of built in storage. Of course the the storage along with the boiler are outside. I have thought about maybe using a few old 50 gallon hot water heaters to use for storage in the house. I know most of the guys on here that have indoor boiler setups use alot more storage as in 1000 gallons plus. I would think the more the better for thermal heat purposes. I like my boiler. I have burned roughly 7.5 chords of wood and have been running non stop since early October. We live in Missouri so not the coldest place to live. Good luck with your project I would think it might make it more efficicent just would be curious how much storage you would need to make it that way.
A traditional outdoor boiler (OWB) could benefit from external storage because the purpose is to provide an efficient place to store btu's which are not immediately needed to meet system demands, and then to deliver those btu's from storage to meet demand when the OWB has fire out or otherwise is not generating sufficient btu's to meet demand. If properly designed and implemented the OWB could continue its burn at a high rate until the wood load was consumed instead of shutting down or idling with wood smoldering because water in the OWB water jacket has reached its high limit.
Storage will not improve the inherent inefficiencies in OWB design or resulting from use of wood which is not well seasoned, including green wood. For example, bhd21478 who lives in MO has burned 7.5 cords of wood in his/her OWB so far. I will assume that most of this wood is not pine or other low density woods. I have burned less than 3 cords of wood, all white or red pine (low density, low btu/cord), and live in a climate much, much colder than MO. My 3 cords are roughly equivalent in btu content to a little over 1-1/2 cords of oak. My efficiency comes mostly from use of a gasification boiler, but also from use of adequate storage. Of course, the space bhd21478 is heating may be much larger than mine, and there likely are other differences in our systems, but generally a wood gasification system properly designed and implemented can be 2 to 3 times more efficient than a typical design and implementation of an OWB system.
Improper design and/or poor implementation of storage in an OWB system could be both frustrating and costly without much benefit. It could actually make the OWB system less efficient. Proper design and implementation of any hydronic heating system is very important for efficiency and safety.
Storage will not improve the inherent inefficiencies in OWB design or resulting from use of wood which is not well seasoned, including green wood. For example, bhd21478 who lives in MO has burned 7.5 cords of wood in his/her OWB so far. I will assume that most of this wood is not pine or other low density woods. I have burned less than 3 cords of wood, all white or red pine (low density, low btu/cord), and live in a climate much, much colder than MO. My 3 cords are roughly equivalent in btu content to a little over 1-1/2 cords of oak. My efficiency comes mostly from use of a gasification boiler, but also from use of adequate storage. Of course, the space bhd21478 is heating may be much larger than mine, and there likely are other differences in our systems, but generally a wood gasification system properly designed and implemented can be 2 to 3 times more efficient than a typical design and implementation of an OWB system.
Improper design and/or poor implementation of storage in an OWB system could be both frustrating and costly without much benefit. It could actually make the OWB system less efficient. Proper design and implementation of any hydronic heating system is very important for efficiency and safety.
I just wanted to add that my house is 3800 sq ft. I have threee hvac forced air handler/heat exchanger setups along with two hot water heaters to provide hot water. I have burned mostly oak accompanied by osage orange. I have partially seasoned the oak and hedge. I usually prefer a mix in loading the thing with some splits along with a few nice round pieces. I really looked hard at the gassification setups such as the garn jr and the eco 60. The eco was mujch cheaper but I would of had to build an outdoor shed for it. The garn jr plus the the storage setup would of placed me close to 20,000 bucks. My boiler was 5900 and I had 2200 in the thermopex and other parts and pieces. The company charge 2000 for labor. They also replaced a hvac system for me it was a 4 ton trane system. My setup was very complicated as my house was added on two different times. If I had a very basic simple setup I would of considered doing it myself as Im rather handy. Very glad I paid someon for this. I basically have unlimited wood supply owning 25 acres of timber. My family also has tons of hard wood for me to cut. I get good burn times and we live very remote so any lingering smoke doesnt bother neighbors. I also wanted to say owb location is everything. We placed west of our house so any winds blow it away from us. I never could of jusitifed the numbers didnt work for payback getting a garn. We should have this setup paid for in 5 yrs.
We have dealt with a number of standard wood boilers that have used our tanks as a buffer.
I cannot recall anyone not seeing better performance due to the buffering that storage affords a system.
I would guess 10-30% better performance, but that is purely a guess. I know there are some folks here who can report their actual benefits.
One I can think of that is not here has an old cast iron Tarm that installed a tank with a solar hook up. They feed a radiant floor and report excellent results.
I will try to get some relative performance numbers from them.
I cannot recall anyone not seeing better performance due to the buffering that storage affords a system.
I would guess 10-30% better performance, but that is purely a guess. I know there are some folks here who can report their actual benefits.
One I can think of that is not here has an old cast iron Tarm that installed a tank with a solar hook up. They feed a radiant floor and report excellent results.
I will try to get some relative performance numbers from them.
maple1
Minister of Fire
That would depend entirely on exactly what kind of indoor boiler - they are not all equal. And how closely its output is matched to heatload.
My old oil/wood unit was a basic water jacketed unit with very poor heat transfer ability. Adding storage to it would have done nothing for me as it didn't have any extra heat left over from heating the house to put into storage. However, as another example, my folks have a Kerr wood boiler with tubes. It spends a lot of time idling, and I think storage would help it immensely.
If you want to add storage to a non-gasifier, that is one case where an oversized boiler would be a distinct advantage.
I used a logwood boiler (not gasification) and built my own storage system. It worked well and helped with the total cost of installing the system, This is my 4th year and I removed the Logwood and replaced it with a Econoburn 100, wow what a differance, wood consumption, ash dumping and heat a lot faster. I haven't even got it dialed in yet. I built my 575 gallon storage system for around $2,000 you could build a 1,000 gallon for not much more. The coils are the big cost in this project. I went small with storage (not sure if I could make it work) now I know it works and I have to build it bigger. 575 gallons is not big enough you need to have 1000 gallon. My house is 2,400 square feet and around 7 years old. I understand the cost up front with a gasser but pay now or pay later. It is tough to do I couldn't do a gasser at first and I saved lots of $$ doing going that route but 12-14 cords a year with the logwood was a lot of work and not much comfort. Just something to think about.
There are good deals to be had on used, non-gassifying, cord-wood boilers--from people switching "up" to gassifyers and pellet-boilers. If going to the trouble of setting up a system, for ANY kind of wood-boiler, sufficient heat-storage is a must. And, any of these systems, if done right will pay for themselves in short order--by petrodollars not spent, and by lessening amount of cordwood needed.
I like the 3-pass, cast-iron sectional boilers like Buderus and Biasi. Of course there are all the earlier Tarm boilers that hold their integrity well. I just installed for a customer, a used, 4-yr old Buderus boiler that was TOTALLY clogged (and that boiler has a huge number of clog-able passages), by the former owner. It didn't work for him because he was burning it w/o storage, and wasn't heating his house--BECAUSE IT WAS CLOGGED w hard, glassy creosote. I installed it w/ 550 gal. of storage (Am. SolarTechnics.), would have gone bigger but space limited. And it is working beautifully. Oh yes, I always install "boiler protection" on the return water--another "must-have." The former owner--a plumber--didn't have that either.
I like the 3-pass, cast-iron sectional boilers like Buderus and Biasi. Of course there are all the earlier Tarm boilers that hold their integrity well. I just installed for a customer, a used, 4-yr old Buderus boiler that was TOTALLY clogged (and that boiler has a huge number of clog-able passages), by the former owner. It didn't work for him because he was burning it w/o storage, and wasn't heating his house--BECAUSE IT WAS CLOGGED w hard, glassy creosote. I installed it w/ 550 gal. of storage (Am. SolarTechnics.), would have gone bigger but space limited. And it is working beautifully. Oh yes, I always install "boiler protection" on the return water--another "must-have." The former owner--a plumber--didn't have that either.
Thank you all for the info. Keep it coming as I am interested to see others setups/advice.
My current plan is a wood boiler to heat storage. I have to still size it but probably looking at 1,000gals+. Mainy will heat the house through a radiant floor system on the 1st and 2nd floors. Basement will have baseboards. I'd like to think I can use the boiler to keep water temp in thermal storage above a minimum while the system uses it for the heating system. Instead of the boiler keeping the system hot and dumping excess to storage. If I can find and aford a gassifier at the time I will get it.
My current plan is a wood boiler to heat storage. I have to still size it but probably looking at 1,000gals+. Mainy will heat the house through a radiant floor system on the 1st and 2nd floors. Basement will have baseboards. I'd like to think I can use the boiler to keep water temp in thermal storage above a minimum while the system uses it for the heating system. Instead of the boiler keeping the system hot and dumping excess to storage. If I can find and aford a gassifier at the time I will get it.
FYI, earlier this summer I came across a used 60kw Tarm gasser for sale in the classified. The owner just bought an apartment building with this unit in it. Was switching over to a pellet boiler. 7 yrs unit. Has at least a 20+ yr life expentacy. 10k+ value new. Bought it for $1700.00. Resold for 4k a few weeks later.
Its worth looking in the classifieds in the spring.
Its worth looking in the classifieds in the spring.
maple1
Minister of Fire
The catch there is, if the boiler doesn't have excess to dump to storage, there's not much point in having storage.
hobbyheater
Minister of Fire
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This non-Gasifier burned around 16 cords per year without storage. When 1,260 gallons of storage was added, it burned around 10 cords per year.
A gasifying boiler attached to the same storage burns only 4 1/2 cords per year!
The wood burned was Douglas Fir and the cords were 4' by 4' by 8'.
I had a Harman SF 260 for about 15 years - If I could have let it run flat out & put the heat into storage, well, life would have been better - No storage meant the auto damper opening & closing about 25 times a day, resulting in a chimney that was so plugged with creosote, impossible to clean that hard glassy stuff out.
Good to know, I have heard others mention this on other threads.
I understand you burning fir, curious what size is your home and type of system is it feeding?
Also I know I can peice it togthor from seperate sources, but does anyone know of an all in one guide/resource to sizing a combo of supplying and setting up a radiant floor system?
Modern Hydronic Heating: For Residential and Light Commercial Buildings
Is that the one?
cowboy3500
New Member
I'm coming along behind and appreciating all the insights into my similar problem. In discussing storage. Would old water heater tanks work? Setup in series possibly? They're cheap enough and already insulated and plumbed.
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