wood chip boiler?
- Thread starter stihly dan
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ponyexpress976
nipple fritters
This little contraption once again has me wondering if it couldn't be adapted for electricity production. Just thinking out loud...wouldnt it be sweet if you could get your winter heat, all your domestic hot water and your lights out of one unit. Primary unit used to make steam for electrical generation and downstream of that a condensor of sorts for your hot water or forced hot air.
Maybe one day.....
Maybe one day.....
Many year ago someone was looking at growing poplar for a renewable energy source, due to it's rapid growth rate. As I recall, it was to be used for generating electricity. I don't know what ever became of the idea. I'm sure that burning chip would work, just not sure how practical it would be scaled down to the homeowner market.
zogger
Tree Freak
I worked at a shop once that did just that, used their wood scrap into a boiler/steam turbine generator to completely power the shop as per electricity needs and heat. Heat included running a big steamer for the wood before processing (cutting on lathes primarily) plus the kilns for drying. It not only did that, but the surplus they sold back into the grid and the owner told me they got a check back every month for about nine grand, 70s money. It was some model GE steam turbine and boiler setup. It was big, commercial size as you can imagine.
The larger the scale the easier it is to do though, they ran two firemen (what they were called) to watch and feed the thing per shift. I have never seena single hyomeowner sized unit, but ya, seems to be a potential market there. It would just need to be REALLY computer controlled with a lot of redundancy and backup.
Perhaps it could be done easier with some sort of stirling cycle engine.
stihly dan
Addicted to ArboristSite
I'm sure theres a way, and someone is holding every conceivable patent to themselves.
You can count on it.
ponyexpress976
nipple fritters
scale of operation always seems to be the limiting factor. Nut it sure feels like we are approaching a point with technology that a home sized system could be run by a smart phone...considering the average smart phone has multiple x's the computing power of what was used to get to the moon.
zogger
Tree Freak
ya, the computing power is there, it is just a big step up from a big hot water heater to a pressurized steam unit and turbine. I know the idea of a home sized heat/hot water/electricity wood fired unit has been kicked around a long time in the alt energy community, but the consensus is for the work and expense involved, it's hard to beat a solar PV/wind/fuel genny/ battery bank combo system.
And if you home made one, then you would have to deal with homeowners insurance and I doubt no matter how good it was built that they would cover it. Or get local muni "permit"ission to even install it and hook it up.
A small turn key unit would be nice, but I have never seen one the few times I have looked around the web, just like co-gen units for factories, etc. The smallest commercial units are just way oversized for a single home, and cost plenty. (that I have seen)
A stirling unit would be easier, if they were cheap enough and big enough, and I haven't ever seen a cheap one of those either.
The only other option that you could proly make at home that would work is start with a gas genny, then make it run on wood gas. If the genny was big enough to require a radiator, then perhaps get some hot water from it as well as the electricity.
TIM81
ArboristSite Lurker
The paper mill i work at just got a big wood chip boiler up and running it runs off ground up pallets(mostly dry hardwood) that are too damaged to repair/reuse and at the moment there are enough pallet companys around that keep up supply.And a guy that was ahead of the curve spent big and got a big rotary grinder that gets towed behind a semi truck that goes to every pallet company and grinds up all the pallets they dont want blows them into semi dump trailers that haul them to the mill. Also not too far away a power plant runs two big chip boilers to make electricity they buy green chip wood (whole tree mixed soft and hard wood) they have a large area to keep flipping the chips i was talking with a guy that works there at boiler school he said they dont have to be dry but they have a level they like to run at for best performance.
Drying wood chips on a small scale can be easily done with a washing machine drum horizintialy mounted/winter in a solar kiln.
I can get all i need free!,problem is how to get them in a stove without a mess?
I have compressed sawdust from my sawmill in coffee cans with a chimney in the center that will burn for about 4 hours.
Trying to get rid of so many splitter chips and sawdust from my woodlot is my goal.
WE energies is building a biomas power plant in northern WI, part of the idiotic energy mandate. I say that because I am paying for it in my bills but none of the output will fed back into the grid for WI. ( nice hey?) The Chip boilers are all fine and dandy if one has the time and patience to monitor it (as per one of the poster mentioned in the mill installation) So looking at the Mill deal say $ 40k a year for one fireman plus add Fica insurance ect with 2 guys maybe $160k a year. In large scale operation such as this it likely pans out providing there is little down time. On the smaller size or where the owner has to purchase fuel it does not. This generally what has been found to be true in Europe. A lot of these use compressed biomass pucks ( called chips across the pond) There very well could be a future in it, but so far none of the systems overseas have panned out as most installations have been converted back to dino fuel in 5 years. As to cost for home likely looking at 5 grand or so maybe more. One of my customers installed a owb last year all told he has some 10,000 Dollars in it. From all the post i seen here and other sights seems 2-3 years in and problems develop sometimes severe. The average Joe homeowner just is not going to put the maintenance time into this that it requires ( not a set & forget gas furnace) Heck most of them with pellet stoves do not even follow the maintenance on those. Our society is one of convenience if it isn't it is not going to fly.
They have been using wood chip boilers in Germany and other parts of Europe for many years. It is a popular heating/energy alternative because it is easy to process/handle mechanically and therefore people don't have to get their hands dirty. The boiler systems are fully self contained and just have a hopper outside that is filled by the wood chip company when required.
Right now the biggest problem with wood chips is price which is significantly higher than other popular forms of energy. However, I assume it will become more widely spread once more green energy legislation comes in and energy prices go up. I am currently working on a project where we are trying to reduce the cost of producing wood chips and hopefully we can make it a more viable energy option for the future. Processing trees to save the planet, who would have thunk it...
Right now the biggest problem with wood chips is price which is significantly higher than other popular forms of energy. However, I assume it will become more widely spread once more green energy legislation comes in and energy prices go up. I am currently working on a project where we are trying to reduce the cost of producing wood chips and hopefully we can make it a more viable energy option for the future. Processing trees to save the planet, who would have thunk it...
Thank you for beginning my comment. Yes wood chip boilers are very popular here but only on a larger scale for them to run economically. Very few homeowners install wood chip burners. Wood chips are actually the cheapest form of firewood here. By larger scale I mean that many farmers use it to heat their farm and barns, small comunities are jumping on the small scale units with electricity production. Usually they also own a forest so for them using the "non value"(tops, etc.) wood is a easy source of saving.
Important is that the wood chips are very coarse, usually the size of a average thumb not the fine ground stuff. Drying is actually quite easy as long as you have a constant air flow from underneath. The wood chips try to decompose and this in turn set's off warmth, warm air rises up pulling fresh air behind and thus drying the pile of wood chips. This technology has been studied by many universities here and is nothing new.
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ngzcaz
ArboristSite Operative
I have a Shaver outdoor wood boiler. Has a grate and clean out bin below. Air is forced underneath like a blacksmiths forge and comes up thru the grates. Smoke goes up to the top and is forced back down because the chimney extends down in the firebox about 18 inches or so. For the last four years I've been itching to try this since there's a free wood chip pile in a nearby town. The chips are very coarse. Maybe this is the year to try it especially at this time of the year. If it doesn't work, well nothing lost. I can see it smoking a bit until the chips get dried. Of course when it rains and blows my wood pile gets wet and smokes too. The chips may get dried a lot quicker than a wet log. An obvious downside is " how long will a load last ? " My 4 acres of wood is getting more daylight every year.. :msp_biggrin:
I just can't picture myself having a pile of chips w/out a real wood pile to back it up.. :msp_rolleyes:
I just can't picture myself having a pile of chips w/out a real wood pile to back it up.. :msp_rolleyes:
fireman31
ArboristSite Member
Drying and storage of wood chips
I've been thinking that wood chips could be stored in a small grain bin with a perforated floor.The area under the bin could be enclosed and pressurized with a squirrel cage fan. Paint the whole works black and you've got quite a solar dryer.
As for putting them in the bin, a 6" to 10" pipe with a fan could be used to blow them in the top of the bin. Unload them through the door into buckets and into whatever manner of auto feeder you're using.
I like this guy's home built auto feeder: Farm built wood chip heating unit
His method would work pretty well with a rocket stove/boiler
I've been thinking that wood chips could be stored in a small grain bin with a perforated floor.The area under the bin could be enclosed and pressurized with a squirrel cage fan. Paint the whole works black and you've got quite a solar dryer.
As for putting them in the bin, a 6" to 10" pipe with a fan could be used to blow them in the top of the bin. Unload them through the door into buckets and into whatever manner of auto feeder you're using.
I like this guy's home built auto feeder: Farm built wood chip heating unit
His method would work pretty well with a rocket stove/boiler
taskswap
ArboristSite Operative
I just ran some math here. Around here, even if you pay for wood chips they're only $10-$12/cu. yd. Now if my math is right a 4x4x8 cord is 4.74 cu. yds. I dunno about you guys but $50-$70 "per cord" is a freaking great deal if you were actually going to get 1:1 heat out of them compared to standard firewood. And I'd think that you'd get more (assuming they were dry) because they pack more tightly.
At the same time they seem so unapproachable. The ones I've seen online are enormous - sized for heating a school or something. I'm in love with my indoor boiler, and I'd have a stove if I didn't have this. You can get boilers on eBay super cheap - there are guys that pull them out of peoples' houses during renovations, fix them up (mine was pressure tested, freshly painted, and re-lined with new firebrick), and flip them out on eBay. It's hard to imagine the return on investment for one of these things - even a "small" one plus its infrastructure must cost at least 5 figures? No?
I bet you could dry and store them in 55-gal drums. Buncha holes for airflow, they're already black, dry out in the sun, then onto some kind of dumper for loading into the hopper. But wow, this seems really out of reach for residential.
At the same time they seem so unapproachable. The ones I've seen online are enormous - sized for heating a school or something. I'm in love with my indoor boiler, and I'd have a stove if I didn't have this. You can get boilers on eBay super cheap - there are guys that pull them out of peoples' houses during renovations, fix them up (mine was pressure tested, freshly painted, and re-lined with new firebrick), and flip them out on eBay. It's hard to imagine the return on investment for one of these things - even a "small" one plus its infrastructure must cost at least 5 figures? No?
I bet you could dry and store them in 55-gal drums. Buncha holes for airflow, they're already black, dry out in the sun, then onto some kind of dumper for loading into the hopper. But wow, this seems really out of reach for residential.
Maybe this guy has the setup you need? How I Heat My House For Cheap I Canada pt 1 - YouTube He has a ton of good videos up.. He also burns sunflower hulls in his burner. $300 for a year worth. And he's Canadian so you know he knows what he's doing. 
Nofmb
New Member
I manage a company that burns wood chips to run a low pressure steam boiler, and can offer some advice on heating with chips.
It is a struggle to get good performance using chips with a moisture content over 30 percent.
The system we have is a large storage bin that feeds into an auger system for delivery into the boiler. During very cold weather green chips will freeze into a solid block and will not auger.
In the area I live in dry chips are in high demand and very tough to come by. Most of the production is locked up by contracts.
It is a struggle to get good performance using chips with a moisture content over 30 percent.
The system we have is a large storage bin that feeds into an auger system for delivery into the boiler. During very cold weather green chips will freeze into a solid block and will not auger.
In the area I live in dry chips are in high demand and very tough to come by. Most of the production is locked up by contracts.
Interesting, how do you go about drying your chips?
Nofmb
New Member
We burn our own wood waste, most of it is under 15 percent moisture content. We have run into problems when running large amounts of green material. This is now set off to the side and not used for boiler fuel
I have seen a chip drying systems that used a vent pipe coming out of the center of a large pile of chips. The theory was that as the chips sit in a pile bacteria go to work digesting the sugars in the wood, and this generates heat. This heat drives the moisture out of the wood and is vented out the pipe. In theory this makes sense, but I have no idea if it actually worked.
