wood gasification questions

michael terry

does the wood gasification process just involve a lot of excess air to the fire or is there somthing more at work.
how does a wood gasification boiler without a blower motor stack up to one with a blower.

hr

check out the video clip

at this website. The EKO Vimar is the brand I have in my shop.

www.newhorizoncorp.com

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[Deleted User]

Tough to find...

Cut and paste this URL...

http://www.newhorizoncorp.com/offer.php?id=4

It's near the bottom.

Impressive information there HR. Are you seeing it burn as clean as they say? Seems to me when you first load that puppy up that it would probably smoke regardless of the residual mositure content of the wood, no?

ME

hr

much, much cleaner

than a typical OWF. I know because many of my neighbors have Hardy brand OWF's. I get a good hot fire going right off. I cut and chop up old, non recyclable wood pallets to use as kindling. A few shots of some old waste oil and one match get's her roaring in a few minutes.

With the variable speed inducer fan it "watches" the fire and burn quality fairly close.

My wood consumption has dropped considerably from the basic wood burning boiler I used years past.

Some of the fancier gasification boilers have sensors in the flue connector to watch temperature and emissions and adjust air and blower speed.

I'd love to see the offerings at the ISH Frankfurt show this spring. looks like the whole show is geared towards alternate energy.

hot rod

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John Abbott

Gasification boiler

Try www.woodboilers.com The Tarm gasification boiler is just incredible secondary combustion chamber burns white hot and sounds like a jet engine burning. Two weeks of midwinter burning produced about a coffee can full of ashes.There is just about nothing but water vapor coming from the chimney and ona real cold day it only 1.5 feet above the chimney.The company has been in business a long time and the tech support is excellent.

John

michael terry

water storage

are you using heat storage with your system?

Stephen C.

Gasification preferences

Hot Rod,

What considerations or preferences influenced your installation of the EKO Vimar over the Tarm or others?

Tarm and Greenwood are available near me but have not heard from EKO Vimar as to availability.

Are all gasifiers built equal? How to differentiate the good from the bad and the ugly?

Stephen C.

hr

Gasification or pyrolitic boilers

basically all use the same concept whereas the flue gas is pulled or pushed into a ceramic chamber to extract additional energy that normally goes up the flue.

I've installed the Tarm, very nice quality, Dakon PK Pyro, EKO Vimar, Verner and Atmos. Nicer units have more high tech controls and more ceramic lining in the gasification chamber, from what I can see. Also a bit nicer welds and metal forming.

I've been told Vimar builds the Viessman gasification boilers. Also that Buderus may have bought Dakon?

The www.Verner.cz has some pretty impressive control packages that monitor flue gas temperature and quality. also some nifty, small parlor boilers. Aquatherm in Minnesota is importing their biomass boilers.

I thought the Atmos www.atmos.cz was the nicest built of all the units I have installed. I'm not sure they are imported anymore. They were concerened about lawsuit friendly climate, and sheer number of lawyers in the US of A

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Will Merryman

gasification boiler

Check out this boiler. Made in Maine. Quite impressive.

blackbearboilers.com

Stephen C.

More questions

What is the usual or anticipated operating lifespan of these boilers?

What anticipated or potential component failures would there be?
How much service is required?
What is the availabilty of parts and their general cost?

Are the various manufacturer's quoted warrantees realistic and substantial?

Stephen C.

hr

Tough questions

lifespan is almost always related to care and operation. Frequent cleaning of the fire side, and a good corossion inhibitor on the inside would be my suggestions.

Really there are not many moving parts. Basically the inducer fan. Most of those are EFM variable speed, or single speed motors available from the dealer or Johnstone Supply.

I doubt you will find much more than 5 years or so on a HX warranty, but that by no means is the life expectancy. I'd guess without abuse, they should last 15, 20 years or more.

All of the ones I have installed are very heavy gauge boiler plate and even the small KW units weigh 800 lbs and up. Plenty of steel in them. That about 3 times the weight of an equal sized cast iron gas fired boiler.

Lot more variables in solid fuel burning boilers than gas or oil fired. Again mostly operator error related

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hr

S Ebels

Yep, very good questions

Warranty is almost always something you don't really find out about until you need it. The only thing you can go by is the manufacturers track record which can be tough when the compnay in question is new in the business or hasn't been here in the US very long. Tough call either way.

One unit that falls into the category of "a horse of a different color" is the Garn made by Dectra Industries up in Minnesota. They subscribe to the "burn it hot and burn it all" theory of getting the most efficiency out of your wood so strongly that they include the stoage right in the unit. The smallest one they make holds 1500 gallons of water and weighs 3,600 pounds EMPTY. Definitely not a basement type unit. All their models are gasification type with a secondary reaction chamber. Independently lab tested at 75%+ efficiency with many out in the field over 20 years old from their first production in 1978.

michael terry

inducer vs natural draft

does any one care to touch on this subject.
and also the water storage issue, burn it all and burn it hot makes sense to me. a boiler that uses no water storage and shuts the air off when the aquastat is sastified would have to smoke would it not?
mike terry

michael terry

well

cool name but not much info on the web site.or was I on the wrong site.
mike

Stephen C.

Fair comment. We live in the information age and that is a glossy brochure at the fairground. Entertaining but where's the beef. I want to be warmed, not gently amused.

hr

I can't get onboard the Garn concept

Seems to me the very BEST place to store energy is in the chemical form i.e. the block of un-burned firewood. It can stay in that form for many years without de-grading much.

Once you burn the wood efficiency starts slipping away. First the burn efficiency. Next the fire to water heat exchange efficiency. But by far the biggest loss becomes keeping that hot water hot! If in fact the water is contained within the fired vessel then you have both jacket loss and some loss up the flue. As I see it.

I think this is the intent behind the somewhat small firebox in most Euro gasification boilers. Why burn a 300,000 fire when the load never exceeds 80,000?

Really, and ideally you would burn to the load, and only store over shoot amounts. I'd really prefer not to have to supply insulated water storage with wood burners. the reality is they just don't stsrt and stop like a gas fired appliance

This is where the biomass pellet boilers look so much better. Auger in the pellets to meet the load then shut down. Of course pellets, unless you have access to cheap or free corn or grain, cost more than firewood.

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michael terry

looks like

you and I are on the same quest.....which boiler to buy?
I have plenty of wood,seems like a good way to go.

Stephen C.

Quest

It certainly is a quest and only just begun.

I also have plenty of wood available but have no desire to
invest in something inefficient that doubles my effort to harvest sufficient firewood to fuel it.

It is very hard to compare apples to apples when looking at the various manufacturers of wood boilers out there.
It was very simple to eliminate the low tech smudge pots I see around the countryside but evaluating the approach and performance of the gasifiers is more challenging.

I tend to agree with Hot Rod's view of the Garn and the storage losses associated with that much water. Matching the boiler output to the load as much as possible
makes sense. I think that a buffer tank is probably inevitable but much smaller than 1500-3000 gallons.

With the gasifiers does the variable speed fan cause the boiler to modulate its output and by how much, or is it more of an on/off function?

Stephen C.

S Ebels

I would sure like to see

No make that....I'd LOVE to see actual lab tests on all the types of wood burners out there. We'd probably wind up with something like AFUE which is an indicator but not the "last word" so to speak. All of the standard type ODWB's tested in Wisconsin this past Spring were pretty poor with the best hitting a wink above 40%. The Garn was also tested using the same criteria, whatever that was and it delivered 77%+ IIRC.

Thermal losses from the Garn are entirely up to the installer/owner as the unit is field insulated. It's just a bare piece of steel as delivered. If you wrap it with 3" of fiberglass, it will definitely lose a bunch of heat. If a little more care is taken, I don't think the standby losses would be all that huge. My guess is that the drop in efficiency from modulating a solid wood fire would probably be on a par with the jacket losses from the Garn. It's a "choose your poison" type of thing the way I see it.

My first choice would be a modulating boiler that uses a metered fuel supply to eliminate the smoldering effect generated when you shut down a standard wood fire. In other words, pelletized fuel. The problem as Hot Rod says, is that you pay more for pellets and move your ROI further down the road.

hr

350- 500 gal. buffer

should be plenty if the unit is sized close to the design load. Tarm has been selling that size tank with excellent sucess, from what I have seen.

I switched to a pressurized buffer tank last fall and it works much better than my homemade "open" tank.

I found a used 500 gallon Lp tank, which is an ASME listed pressure vessel.

The downside is not being able to stick a bunch of HX tube inside. I may wrap some copper around it for a solar input this spring.

Just be careful with expansion tank sizing when you are dealing with 500 plus gallons across a 60-180F temperature range. Takes about $250.00 worth of tank

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Tom R.

Wood fired hot water generators

We installed a Tarm three years ago. The crucible still looks like new. The firebox is scraped clean weekly and tubes brushed every three weeks or so. The unit is fired year long, including summer for domestic H/W. The system is 50/50 propylene glycol with corrosion inhibitor. We heat 3000 sq. ft. of living space (baseboard)and a 900+ sq. ft. attached garage (at 55 deg.-radiant slab). The unit is rated at 110,000 BTU and never fires continuously. Lowest OS temp. about -30 (maybe 5 to 10 days a year). Average heating degree days 7500 yearly. Last year we burned under 8 full cords of wood (maple, beech and oak) and 30 gals. #2 F.O.(while away). We are paying average $106.00 per cord for blocked (round) 18" pieces. That would be about equal to $330.00 at $2.20/gal. for #2 F.O. We saved about $1800 on fuel. That' s a payback period of less than 3 years for the cost of the boiler installation. But I had to split and handle the wood, empty ashes, and keep the fire stoked. Is it worth it? You need to decide for yourself, but I am completely happy with the quality and ease of service of the Tarm unit. As for combustion efficiency, it seems as good as the existing oil fired unit. No visible indication that it is running, except heat waves and some vapor if the flue gasses go below condensing temperature on a cold day.

Stephen C.

Positive recommendation

That is a great recommendation. Payback of three years sounds wonderful. Is that really (3 X savings on prior annual fuel usage = Cost of boiler install)? From the preliminary information I have gathered that seems exceptional. Did you install a buffer tank? Presumably the boiler is in the attached garage so no underground lines were required?

Stephen C.

Tom R.

Installation

is in the basement, piped in tandem with the oil fired unit. It uses a separate chimney from a prior wood stove. Spent about $500 to inspect and replace about 6' at the top. The two boilers are about 20' apart. There is no piping outside of the building. Yes, the savings is based on the use of wood v. #2 F.O., compared to the cost of the boiler, piping and controls. The only outside labor was for the chimney. Fuel prices being unpredictable, the comparison is for today, but all fossil fuels will probably cost more than renewable sources in the near and distant future. No buffer tanl as yet, but we are still considering it. Room inside the building is the issue. (really need to clean up the cellar)