wood gasification boiler/furnace experiences

[58hydraglide]

Does anyone here have any first or secondhand experience with the cleaner burnig tarm, greenwood , garn etc. gasification furnaces. I have been doing a lot of research on the subject and am looking at going from woodstove to outdoor wood heat. The current issues regarding OWB's and emissions is getting pretty close to home and these seem to be the next generation of boilers. If i am going to install one I would prefer to go with one of the cleaner burning models as I'm convinced that this current issue is going to be get larger and more widespread. I am curious how these measure up in regards to wood use/ whole house heating capabilities as compared to the conventional OWB's I understand the theory on the gasification units, but are there any units similar that don't require additonal air introduction (blower fan)
I know one of the larger OWB manufacturers claims the there's is the cleanest burning, but there emissions charts compare themselves with other boilers and their baseline is what % GREATER their competitors emissions are as compared to theirs. Not ACTUAL particles per hour measurements. Leaves me somewhat skeptical.

 

[doubletodd]

the key to gassification seems to be a larger liquid storage capacity where the water is heated and stored firing is done in two hours very hot burn and then does'nt need to be fired again for about 12 hours. sounds interesting, but would like to see if one could be homebuilt as I do not have $10-15k to spend at the moment

 

[windthrown]

Three issues here: one is that the gassifiers are not really outdoor boilers (none are sold as such anyway). Another is what 2todd says about the large water storage tanks required to go with the gassifiers. Also the gassifiers tend to cost a lot more than OWBs. These are the basic difference between the typical outdoor wood boilers (OWB) and wood gassifiers (WG). There is also the issue of efficiency, and clean burning, which the WGs tend to do better (though there are some clean burning OWBs being sold now, from the likes of CB). Another aspect is that OWBs will burn ANY type (and size) of wood in any orientation; wet, green, rotten, seasoned, dry, or scrap... whereas the WG will only burn specific sized and placed seasoned and dry wood.

We did not buy a gassifier here becasue of the costs, and we do not have the space inside the house, or on the carport slab for a gassifier and water tanks. If we did, I would have opted for building a Russian style fireplace instead, and used bricks for storing the heat instead of water tanks with a WG system. The Russian fireplace works the same as a WG; burn a small fire fast and hot and store the energy. In contrast, the OWB burns slow and long, and heats just enough water to circulate into some type of heat excahngers. In their design, the energy is stored in the unburned wood in the firebox.

 

[doubletodd]

where can i find more info on russian fireplace,I have lots of bricks!

 

[grandpatractor]

where can i find more info on russian fireplace,I have lots of bricks!

Some of your kids would probably like that russian fireplace.:monkey:

 

[windthrown]

Russian Fireplace information and designs are hard to find. I have only one out of print book on fireplaces that has anything on them. Most of the stuff is in Russian... and impossible to read.

I do know a guy that has a CD for sale that has details, animation and plans for five types of Russin/Skandinavian fireplaces online: His name is Stanley Petroskey and his web site is:

http://www.singingfalls.com/masonry_furnace.html

I have seen his Russian fireplace, and I can attest that it works! If you have a lot of bricks, that is the way to go!

 

[doubletodd]

Some of your kids would probably like that russian fireplace.:monkey:

yeah, maybe they have some ideas. grandpatractor is referring to the fact my wife and I adopted two russian children. andrei,12 and masa 11. I amm sure there are many simple types of heating systems in russia. they seem to live much simpler than we do, and thanks for the info. p.s. got that fikers yesterday and whacked a bunch of oak with it today

 

[doubletodd]

hey I just hit 100

 

[KsWoodsMan]

My understanding of gasification differs from what you described. At least in "the key" to it. OWB's in general store a large amount of heat in water/glycol.
In a traditional boiler setup the 'water' is heated by the primary burn. Any unburned smoke or gasses goes up the flue pipe. With Gasification the primary burn is to extract the volital gasses to be used as the fuel for the secondary burn. The volitales, smoke and particulate matter are burned to create the heat needed to raise the temps of the stored 'water'.

The wood is pyrolized (sp?) or partially burned releasing the volitales (smoke). When heated fresh air is introduced, at the correct ratio, to the hot gasses you get a complete combustion. Resulting in lower exhaust emmisions. This secondary burn is what heats the storage tanks. It might be a consistant small burn happening for a longer period of time maintaining the temperature of the stored 'water' or an occasional fast burn when additional heat is needed for recovery.

I would opt for the first method of a smaller and possibly more efficient burn over a longer period of time that had the capability of scaling up when needed for additional heat. As opposed to smoldering for long periods and going to an occasional 'hot burn' that is only efficient when burning at maximum.

The first method might use more fuel maintaining a small efficient fire but should produce fewer emmisions over the same season of burning. In Whole Gasification should be more economical in terms of total fuel used during the season. Since all or most of the fuel is being consumed either in pimary or secondary burn instead of allowing part of the useable fuel to be wasted going up the stack as particulates or unburned smoke. I have heard the difference to be in the order of 50%-70% less wood used. By utilising more of the available fuel efficiently this is within reason.

I am seriously considering building a downdraft gasifier/burner to replace my current wood burner. And hoping to raise the efficiency from about 25% to better than 65%. Less wood across the hearth translates into less to haul back outside.

 

[HEAVY FUEL]

hey I just hit 100

Yep, he's hooked!!!:biggrinbounce2:

 

[ktm rider]

I have never seen a gasifier in action but my co worker bought an AHS gasifier for his radiant heat system and he loves it and couldn't be happier. I don't think the AHS requires a water storage tank, but i could be wrong about that.

 

[windthrown]

This one seems to marry all the aspects of a traditional OWB and a WGB into one.

Good points:
-EPA approved
-Outside with the wood
-Large filrebox, large wood capacity (less splitting)
-Low smoke, emissions and heat exhaust
-Long burn times
-Wood gassification for high efficiency burning

Not good points:
-New company, has not been around
-Spendy; $10 grand for one that fits out size and needs
-Not sure of some aspects of the build quality
-Heavy mothers... would be expensive to ship

However, it is not the only EPA certified clean burning OWB. Central boiler has the E-Classic 2300 OWB that has qualified for the U.S. EPA (OWHH) program.

 

[windthrown]

How long is a while? I have seen many OWB companies come and go. Too many, really. For 10 grand... I am leery of buying from a new company. Not that I am looking to replace the CB we have here now, but if the efficiency is that much better, it may be worth it to replace it (already plumbed and a slab foundation). Easier to cut and store and load half the wood.

 

[blackdoggy]

the key to gassification seems to be a larger liquid storage capacity where the water is heated and stored firing is done in two hours very hot burn and then does'nt need to be fired again for about 12 hours. sounds interesting, but would like to see if one could be homebuilt as I do not have $10-15k to spend at the moment

If some one gives me the plans I have a full shop here I can use to build one not to mention for a few $$ I have a retired certified welder I can get to come over to do the exacting welds. I will have in a few months a freshly remodeled home I can heat with it which I will run radiant floor heating though.

 

[doubletodd]

good Idea, I hope it works out.

 

[Brad DeBoer]

You can run a wood gasification boiler without storage. I have a Tarm Excel 2000, which is a combined wood/oil (or gas) boiler. Picture it as the standard Tarm wood boiler with an oil furnace added to the back. We ran the unit for three years before adding storage to it, and it worked well, as long as it didn't get warmer than ~40 degrees outside. Once it got to 40, the boiler would sit and smolder for long periods, so we would let it run oil.

Two years ago, I installed the 620 gal. heat storage system from Tarm. Since then, we've burned less than 100 gal. of oil, which has been a real cost savings with oil prices these days. We run it all year, including in the summer for domestic hot water. I light the boiler once a week and get the tank up to 180 degrees, and that lasts a family of four the entire week... If I had to do it over, I'd buy a wood-only boiler and use electricity for a backup so I could do away with the oil altogether.

The primary disadvantage to the Tarm over an OWB is that it's pretty picky about wood. The wood needs to be split pretty fine (>6"), and it needs to be dry to run well. I'm into some pretty green wood right now, and it's not that happy burning it. It will, but it's nowhere near as efficient and much harder to get the fire going than when the wood is dry. My dad has an OWB, and that thing will burn anything that fits through the door....

Brad

 

[sthomps]

Hs Tarm

I'm been running a HS Tarm solo plus 60 (just wood) for the last three years and I like the boiler, but it is true what Brad said about them not liking the 40+ temps. I'm not running a storage tank but I have not had the oil furnace in our house run for the last couple years. I think they don't burn as good when it gets warm out because the fan never comes on to let it burn right. I have my boiler in my garage that's about 130' from my house, and I'm glad I didn't buy a OWB just because of the volume of wood they use. A few people that live close by use about double what I do for a very close square footage. Mind you they can burn bigger lengths of wood. I can almost heat my garage that's 24'x33' with the heat that comes off of my insulated boiler, so that heat is lost to the outside air on a OWB. I also like the fact that when its blowing snow and windy out, I only have to get to my garage, then I can take my time and load my boiler, clean out the ash,wash the truck...

 

[Tim321]

"Blue Forge" wood stove

Here is a link to company that has a video of there unit burning. I looking into getting one of these last fall, cost was about $8500. He also said this is not an outdoor unit, should be placed in an unattached garage.

http://www.ka-lesdistributing.com/

 

[sthomps]

Hs Tarm

I was also going to say in my last post that my boiler also does not like to burn wet wood, but I don't think that just because a boiler puts in enough air to burn wet wood makes it a better boiler. Burning wet wood seems like a wast to me. It takes as much work to get it to the boiler, but you don't get as much heat out of it.
Kind of on the same topic, how many people that are running a OWB or an indoor one like me are only running the hot water to the house when it is demanded? It seems like everyone I have talked to runs the hot water pump all of the time and controls the heat in the house by turning the fan on and off, if they are using forced air. I know there is heat loss through the ground even if I only run the pump when needed.

 

[scryan]

Does anybody have experience with a Garn system? I've read a lot of positive things about their gassification system, but nobody in Upstate NY seems to have heard of them (or really of gassification for that matter). Any idea how much they run?

Who are considered the best companies on the market for wood furnaces/boilers?