Blue Forge OWB

[Eric Johnson]

I saw one of these at a trade show last week. It uses the same gasification technology as most other gasifiers, but is designed to be installed outside. The dealer told me they work well, but run about $9,000. Like most other gasifiers, dry wood is the key.

(broken link removed)

I also saw one of the Alternative Heating Systems indoor gasifiers at this show (the Lake States Logging Congress). It's the one built in Pennsylvania, not the one from New York with a similar name. Built like a tank, with all kinds of fancy refractory brick, a stainless steel firebox, cyclone, and who knows what all else. They were selling the display unit, a 130,000 btu/hour model at a "show special" price of $10,500. By comparison, my 205K btu EKO cost $6,000. But the build quality is on a whole different level. Probably like comparing a Camry with a Ferarri.

 

[carpniels]

Hi Eric,

Do you mean yours is the ferrari and the other is the camry? Otherwise that comparison does not make sense. Ferraris are (were) notorious for poor built quality and for needing a lot of maintenance and being fragile. The Camry however is cheaper and runs forever without much maintenance. But you can't go 200 mph!!

Anyway, you can do a lot of repairs for $4,500 price difference. That is almost double of what you paid.

For that money, you can get a $2,000 gas hot air heater installed and heat with gas. Unless you have free wood, you will never earn back the difference between $2,000 and $10,500 over the lifespan of that heater.

Same is true for hybrid cars: the premium for hybrid (several $1,000s) is not worth the 20% gas savings unless you keep your car for 10 years or you drive 50,000 miles per year. And almost no one does either!!

Carpniels

 

[Eric Johnson]

Obviously, I know a lot more about boilers than I know about cars.

Mine is the Camry. I'm happy with that. I was going to use Jaguar as the pricey example, but I know they're basically stylized junk.

We still on for Sept. 22?

 

[keyman512us]

Eric...
Does that "Blue Forge" model use a fan to induce that draft???

If so what amount of electricity does it use???

Kinda cool to see the flame that thing produces..."Can feel the Btu's just looking at it".

 

[Eric Johnson]

All gasifiers have at least one blower. My EKO has two. That's how you get the gas from the upper combustion chamber into the lower gasification chamber. So, yes, the Blue Forge has at least one, but have no idea how much current it draws. Probably not a whole lot.

My favorite hunting quote of the week: "I hunt because the voices in my head tell me to."

 

[BrownianHeatingTech]

All gasifiers have at least one blower. ... That's how you get the gas from the upper combustion chamber into the lower gasification chamber. So, yes, the Blue Forge has at least one, but have no idea how much current it draws. Probably not a whole lot.

That's incorrect. There are plenty of natural-draft gassifiers. HS Tarm. Greenwood. And, looking at the designs I've seen on the Web, I'd say that the Blue Forge as well as Black Bear Boilers are natural-draft units, too. There are probably others that I haven't stumbled across.

Draft from a decent chimney is plenty to pull the gasses through the secondary chamber.

Joe
Brownian Heating Technology
Northwood, NH

 

[webbie]

Tarms use a fan - I know because I was the importer and wrote the owners manual and literature!

Greenwood may be natural draft, but it is more of a "downdraft" unit than a gasifier (IMHO).

Yes, in theory any stove that burns the gases is a gasifier - an Everburn VC is a gasifier. But to get to 100,000 BTU and highly tune the combustion, the fan it the way to do for central heat.

The movie certainly looks and sounds like fan - unless they had a 25 foot chimney we didn't see.

 

[BrownianHeatingTech]

Tarms use a fan - I know because I was the importer and wrote the owners manual and literature!

Sorry, don't know why I typed Tarm in there. Probably because I'm hooking one up next week and was completing an order for pipe while doing this.

Edited to add: even so, the fan is not necessary; it could be replaced by a damper. You would just need more chimney draft to account for its removal.

Greenwood may be natural draft, but it is more of a "downdraft" unit than a gasifier (IMHO).

Yes, in theory any stove that burns the gases is a gasifier - an Everburn VC is a gasifier. But to get to 100,000 BTU and highly tune the combustion, the fan it the way to do for central heat.

That doesn't make particularly much sense. In what way, precisely, is Greenwood not a gasifier?

The movie certainly looks and sounds like fan - unless they had a 25 foot chimney we didn't see.

I don't hear a fan, listening to it here...

What is the notion that a fan is needed? What would it do? Induce draft? Guess what a chimney does? The source of the draft is not relevent to the ability to gasify the wood. As far as the wood is concerned, it could be a giant toking on the flue pipe, and it will still do its thing.

Joe
Brownian Heating Technology

 

[Eric Johnson]

This thread provides ample evidence that I should stick to commenting on what I know. The EKO 60 has two blowers. I don't recall seeing a fan on the BlueForge but as an outdoor unit, I'd be surprised if it doesn't have one.

EDIT: And it does. Here's a quote from the website:

"The two primary concerns of wood stove and boiler owners are too much smoke out the stack and burning excess amounts of wood. The "Blue Forge" wood stove is a gasification unit. It smokes less because it burns the emissions coming down from the primary fire box in a secondary burn chamber that has air being injected with its own fan!"

 

[Burn-1]

Blue Forge definitely has a fan. This is stated on their site. I clipped a section and highlighted it below as a pic.

Greenwood, Adobe, and Black Bear are all very similar either updraft gasification/downdraft exhange or vice versa and if you look at Fred Seton's site Seton boilers toward the bottom you can look at his rather disaparaging notes on how these boilers are all off-shoots of his original design. I don't think any of them have forced induction of the flame path.

Tarm, Garn, AHS, Orlan, (Eko & others), Atmos, & Kaukora all have forced induction with fans, (forgot Blue Forge above)

I thought I was dead set to get an Eko 40 but I just saw a natural draft downdraft boiler at Windy Ridge in Tamworth, NH made by Kaukora, (Finnish). It's small setup which might help with where I can put the boiler. Only 85K BTU, but I think that might be enough now that I have installed new windows and upgraded the exterior insulation. The boiler is listed at $2,700 but the ~500 gallon heat accumulation tank with internal heat exchangers is $3,300, more than the boiler. I've attached a quick pic of it's burn system. The larger Kaukora units all have forced induction so like Craig was saying earlier, if you want more BTU's you need more wood and more air to combust with it.

EDIT: Went to stop the dog barking before posting and see that Eric noted the Blue Forge fan before me

 

[Eric Johnson]

Say hi to Tim at Windy Ridge for me, Burn-1. I thought all he sold was logging equipment.

Getting back to the draft, the Black Bear Boiler implies that it uses natural draft, but doesn't actually say it on their website. Adobe gives you the option of going either way.

Adobe makes a pretty bold claim on their website. Something like "If you have seasoned firewood, it's valuable. Sell it. Then buy some green, unsplit wood for your Adobe. If it will fit in the door, it will burn it."

I'm really going to have to verify that claim in person next time I'm in Maine. The factory is just outside of Bangor.

My local Adobe dealer stumbled across one of my threads on this board and emailed me offering me a "special, introductory" deal on one of their 150,000 btu/hr units. I think it was around $8,000. The physical dimensions of the thing are too big for my available space in any event.

 

[Nofossil]

I'll try to restrict my comments to what I know from first-hand experience:

My EKO and my brother's scratch-built gasifiers will burn via natural draft, but only barely and only with ideal conditions. Part of the problem may be that the flue gases are so cool that there isn't much draft, even with a 32' chimney. Part of it may also be that the air intakes are too restricted by all the induction hardware, but it's critical to have some mechanism for modulating output. On the EKO, the fan is a multi-speed unit which throttles back to limit water jacket temperature.

On the green wood topic (this thread is getting fragmented) has anyone heard of this approach? Sounds interesting. Basically, it appears to be a forced updraft 'one batch per burn' approach to burning wood chips with effectively a gasification process.

http://www.sredmond.com/vthr_index.htm

The guy lives in the same town as one of my brothers - maybe I'll pay him a visit.

 

[Eric Johnson]

Yeah, this thread's a goner, but I'm learning a lot from you guys, so we'll just start another one when it's appropriate or the spirit moves.

Now that we're talking about natural draft, I used to have a Tarm knock-off (Marathon) boiler that used natural draft in a gravity feed system (big, old two-story house with big pipes and cast iron rads) that worked great, especially when the power went out, which was pretty often in the Adirondacks. To run the EKO on natural draft (assuming the optimum conditions), seems to me you'd need to modify it so that it didn't overfire. After all, that's what idle is all about--the fan kicks off and the process slows to a crawl or stops altogether.

People have been gasifying green wood chips in Vermont for nearly 30 years. My first exposure to the process was a guy named Cliff Valley in White River Jct. (or maybe it was Rutland) back in 1983. He developed and patented a wood chip gasifier called the EnerChip. Just a big chip hopper sitting on a nozzle, I guess. Anyway, it didn't have a pressure vessel--you had to hook it up to a conventional boiler. It was basically just a chip-fired gun. He showed me a couple of units in operation. Even though I didn't really understand what I was looking at, I remember that it seemed to work pretty well.

He was bought out by an outfit called ChipTec, which eventually focused on bigger projects, like school wood heating systems. I don't think they make a residential chip burner anymore. I don't know anyone who does.

The one thing I remember about the chip thing, since I considered getting one at one time, is that you need a pretty special chip for them to run right. A conventional whole-tree chip couldn't cut it in an EnerChip. You either needed clean sawmill chips (expensive and hard to get because the paper companies buy them all up) or a chip produced by a Valby wood chipper. That kind of killed the market for these amazing gasifiers, since you need a readily-available fuel supply to convince anyone to buy one, and such a thing doesn't exist, at least where "specialty" chips are concerned.

And I don't recall if the EnerChip had a blower. I do have a picture of Cliff and his rig around here somewhere, which I will scan and post in case anyone is interested.

 

[Nofossil]

This is now officially a wood chip thread....

ChipTec does indeed make industrial gasification chip burners. Several schools near here use them, and a local sawmill burns bark(!) in theirs to heat their kilns. I don't know the technology, but they can burn green chips.

I think on a large enough scale, you can drive off the moisture as the chips are fed into the system. Probably not practical for a small system. They make nothing on a residential scale.

 

[webbie]

"How is the Greenwood not a gasifier?"......

Well, they are all just made up terms.........but as I said, a new VC or Harman everburn and many other non-cat stoves are "gasifiers" also. Gasifiers is just a marketing or descriptive term which we have chosen to apply to central heaters (or industrial devices) which make certain that they burn all the wood gas.

The fact is that you could also claim that it's possible to have an efficient oil burner that didn't use a "blower" in the burner.....yes, with enough draft and lots of other balancing. But the Tarm gasifier and others should work well with NO chimney (outside as a display in my case) or with a 15 foot or a 25 foot chimney. The same is not true of natural draft units.

Although I left the door open (no proof at first) that this blue thing might not have a fan, it would be defying the laws of physics unless the web site told them to have a 25 foot insulated stack on top of it. Also, that video certainly looked and sounded like "fan forced" combustion.

In the case of central heaters - oil, gas....and, in this case, wood - there is some benefit to the unit being able to step up to the plate quickly and deliver the full rated output. This is what the fan does. This differentiates them from virtually ALL other wood appliances, which often never (or rarely) reach their rated output. Certainly there are other advantages to natural draft appliances.....

But, for my own purposes, I do define a residential gasification boiler as one which usually has a fan....only semantics, of course. But it does help to classify things into groups. The Greenwood is more of a "cooker", where the large amounts of firebox refractory AND the downdrafting together result in an efficient burn. But it is (I think) related to the chimney draft to a certain extent. I have seen them burn nice at the trade show, though, with a relatively short chimney.

As an aside, there have been pellet stoves designed without blowers - but they have not succeeded (to my knowledge) of combining the control, efficiency and output of fan-forced combustion.

 

[Eric Johnson]

I prefer the term "forced secondary combustion," although "gasification" sounds more exotic.

We fired up the fireplace with some of that dry beech last night and inefficient as it is, that's all secondary combustion going on once the thing gets going, right? I noticed that if you turn on the ceiling fan in that room, the fire really kicks into gear.

Getting back to what Craig was saying, I noticed a big difference when I went from a natural-draft boiler (Marathon) to a forced-air rig (Royall). I was used to waiting around for the Marathon to get up to speed. With any kind of wood burning, keeping the house warm is a momentum thing. That's especially true with a natural draft, gravity-circulated boiler. With dry wood and a blower, however, the combustion side of the equation is a lot easier to manipulate.

 

[Eric Johnson]

Tarm, Garn, AHS, Orlan, (Eko & others), Atmos, & Kaukora all have forced induction with fans.

If the only thing I based my buying decision on was the name, "Atmos" would win hands down.

Sounds like a comic book superhero, doesn't it? "Atmos uses his super powers to turn pollution into energy!"

Or maybe a Greek god. "Atmos, God of Gasification." He points his finger at you, and you're toast.

 

[BrownianHeatingTech]

But, for my own purposes, I do define a residential gasification boiler as one which usually has a fan....only semantics, of course. But it does help to classify things into groups. The Greenwood is more of a "cooker", where the large amounts of firebox refractory AND the downdrafting together result in an efficient burn. But it is (I think) related to the chimney draft to a certain extent. I have seen them burn nice at the trade show, though, with a relatively short chimney.

So your claim of a needing a very tall chimney is sort of moot, isn't it, since you admit that you have actually seen natural draft gasifiers running "nice" with a very short chimney?

Fans aren't all that special. A greenhouse a few miles from me heats with a Woodmaster. That has a fan. Let me tell you, it ain't exactly running clean and efficiently, judging by the small valley it fills with smoke when running.

If it burns the wood gasses, it is a gasifier. How it does that isn't relevant. Specifying a fan is like saying that the car which holds the diesel land speed record isn't fast, because it isn't powered by gasoline. When it comes to naming, who cares how it achieves the desired result, as long as it does?

Fact is, I'd prefer a system that doesn't have a fan; I have lots of customers who have partial or full solar-electric, and every watt counts. Fans are nothing close to efficient, even when using the best PSC and ECM motors. The less power that they use, the better. Which is not to say that I wouldn't sell a system with a fan; I stumbled across this thread while searching for information about the Blue Forge, as I'm looking to move away from Greenwood (for logistical reasons; I have nothing against the quality of the product). But I do consider a fan to be a drawback, in terms of power consumption as well as being an extra moving part to break. I'll accept one if a product otherwise seems to be impressive, but I don't call it a benefit.

Joe

 

[Eric Johnson]

Having owned and operated both a natural draft/gravity feed boiler and a forced draft, pumped water system (both conventional combustion), I'd have to say that the former was a more satisfying holistic experience, while the latter was more satisfying from a performance perspective. If you are a motivated homemaker, then getting successfully in tune with your heating system and the weather forecast is a satisfying accomplishment. You're heating your home with a renewable fuel without the benefit of electricity. How much better can it get than that?

If, on the other hand, you have a more erratic schedule that demands a relatively quick response time and some horsepower to back it up, then I believe a forced-air/pumped water setup is probably preferable. Like Macs and PCs, there's plenty of room for both, and applications where each one is superior. You're not going to do under the floor radiant, for example, without a pump. Your fancy computer-controlled gasification boiler, on the other hand, isn't going to get you through an extended power outage, regardless of how efficient it is.

The beauty of the Tarm-inspired bi-metal draft control (is it Amark or Ammark?) is that it automatically modulates the air flow depending on the temp. of the boiler. You can't get much more in the way of beautiful simplicity than that design. But I'll take a fan any day that I want some real performance on short notice.

By the way, welcome to the Hearth.com forum, Joe. I hope you stick around and let us know about your various installs and thoughts on gasification. I know there's a small, but dedicated, element on this site committed to wood-fired central heat, and your thoughts and observations are obviously more than welcome. Me, I'm always looking to learn more. Gasification is a whole different game, from what I can tell, and good information is always at a premium.

Ever do a Garn install? A friend of mine has a sawmill and a couple of Garns. He also has a Central Boiler OWB for burning green slabwood. Each probably has its place.

 

[webbie]

No problem with however a person wants to define gasify......

BUT, it does appear that a lot of modern gasifiers do press the gases to an area below the firebed, while older Tarms, Riteways and newer greenwoods, VC's, and other natural draft units are more "crossdraft" or "partial downdraft".

What make me think of this is a stove designed by one of the first top engineers in our field - it was an attempt at a clean burning stove which pulled the gases directly down through the center of the grate.......well, as you might guess, the design failed because of the reasons given here earlier - lack of sufficient or balanced draft.

They ended up adding a cat to it in order to pass EPA, but that made it ever worse...chimney wise. here is a pic, the lower glass area was for viewing the down drafting fire.

 

[BrownianHeatingTech]

Having owned and operated both a natural draft/gravity feed boiler and a forced draft, pumped water system (both conventional combustion), I'd have to say that the former was a more satisfying holistic experience, while the latter was more satisfying from a performance perspective. If you are a motivated homemaker, then getting successfully in tune with your heating system and the weather forecast is a satisfying accomplishment. You're heating your home with a renewable fuel without the benefit of electricity. How much better can it get than that?

If, on the other hand, you have a more erratic schedule that demands a relatively quick response time and some horsepower to back it up, then I believe a forced-air/pumped water setup is probably preferable. Like Macs and PCs, there's plenty of room for both, and applications where each one is superior. You're not going to do under the floor radiant, for example, without a pump. Your fancy computer-controlled gasification boiler, on the other hand, isn't going to get you through an extended power outage, regardless of how efficient it is.

I wasn't suggesting gravity feed... hydronic pumps are light years more energy efficient than fans, so it doesn't require a large amount of power to operate a hydronic system. Most of the wasteed power in modern hydronic systems comes from redundant transformers. Nearly every major control is going to have a 24V transformer in it, to make that control "self-supporting" in any application. I know quite a few folks who have ripped out all those transformers and then installed a single transformer and wired all of the controls to it. When you can actually bother with things like that, and see a useful change in power consumption, that tells you how much more efficient pumps are than fans.

The beauty of the Tarm-inspired bi-metal draft control (is it Amark or Ammark?) is that it automatically modulates the air flow depending on the temp. of the boiler. You can't get much more in the way of beautiful simplicity than that design. But I'll take a fan any day that I want some real performance on short notice.

Ideal recovery rate comes from having plenty of heat on hand. Large water tanks give you that. I've seen some of the Dumont installations in Maine with 5000+ gallons of storage, and I think one was at 10,000 gallons. That house was an old (read: drafty) farm in the mountains (figure -20F temps for the heat loss), and was around 2000-2500 square feet. Basically, they would spend a day tending the fire, then have enough heat stored for three days, during the majority of the heating season.

By the way, welcome to the Hearth.com forum, Joe. I hope you stick around and let us know about your various installs and thoughts on gasification. I know there's a small, but dedicated, element on this site committed to wood-fired central heat, and your thoughts and observations are obviously more than welcome. Me, I'm always looking to learn more. Gasification is a whole different game, from what I can tell, and good information is always at a premium.

Thanks. I was originally (years ago) just interested in finding an inexpensive way to heat a farm with some greenhouses. Then I realized how big this market really is. Especially with the cost of oil going so steadily up. So, once I started my own company, I decided that I would make wood a central theme in my business. Despite the fan thing, I'm thinking the Blue Forge is looking to be a very good addition. I spoke to the owner of the company a few days ago, and he seems to know what he's talking about. I have an prospective application locally that will hopefully be good for one of them. The owner is familiar with outdoor wood boilers, so I feel comfortable trying a "new product" with him, since he will actually be able to give me meaningful feedback on its performance. If things work out, these may actually become a significant part of my line, except for indoor applications, since they don't have UL listing.

Ever do a Garn install? A friend of mine has a sawmill and a couple of Garns. He also has a Central Boiler OWB for burning green slabwood. Each probably has its place.

Nope. I've never actually seen a Garn; I don't believe there are many in this area. NH is, for obvious reasons, big territory for Tarm. Central is very big. In my immediate vicinity, Woodmaster is the biggest name, as the nearest dealer is about a mile from me and they sell quite a few.

Joe Brown
Brownian Heating Technology

 

[Eric Johnson]

The dealer I bought my Orlan from sells the Blue Forge. I saw it at his display at a trade show in Michigan and it's certainly a substantial looking boiler.

Speaking of hot water storage, I'm scrambling around trying to design a couple of heat exchangers for my 1,000-gallon tank. I have about 200 feet of rigid copper that I want to tear out and replace with pex-al-pex, and use the copper to make the hx. A conventional heat-loss calculation for 1" copper comes out to about 750 btu per foot per hour, meaning that it would take 200 feet to transfer 150K btu/hour into the tank. But I've been advised that I can probably get away with less, for a variety of reasons.

If you were me, how much copper would you use for each one (heat recovery on the top and heat storage on the bottom) and how would you build it? I know the fittings add some surface area, but they are also potential leak sites. Would you put a lot of copper into smaller, more compact hxs or spread it out into longer runs? My tank measures roughly 4x6x7'

 

[BrownianHeatingTech]

Speaking of hot water storage, I'm scrambling around trying to design a couple of heat exchangers for my 1,000-gallon tank. I have about 200 feet of rigid copper that I want to tear out and replace with pex-al-pex, and use the copper to make the hx. A conventional heat-loss calculation for 1" copper comes out to about 750 btu per foot per hour, meaning that it would take 200 feet to transfer 150K btu/hour into the tank. But I've been advised that I can probably get away with less, for a variety of reasons.

Heat transfer is flow (GPM) x delta (degrees F) x 500 So you could get 150k btuh by pumping 10 GPM and having a temperature drop (gain on the recovery coil) of 30 degrees. If you were only getting a 15 degree drop over the length of the coil, but could manage 20 GPM (not that you'd want to run 20GPM through 1" copper), you would get the same output. Similarly, if you could get a 60 degree drop, you could get by with only 5 GPM.

Which is to say that the larger the coil's surface area, the less flow you need, which means smaller pumps and less stress on them. Expensive as copper is, small coils are generally not a good idea.

If you were me, how much copper would you use for each one (heat recovery on the top and heat storage on the bottom) and how would you build it? I know the fittings add some surface area, but they are also potential leak sites. Would you put a lot of copper into smaller, more compact hxs or spread it out into longer runs? My tank measures roughly 4x6x7'

The length of the coils should be balanced, unless you have a lower heat demand (heat loss for structure) than heat gain (output of boiler). Since it sounds like you want to use what you have, I would suggest simply figuring the ratio of the heat demand to the boiler output, and dividing the copper that way.

Typically, an input coil works well in a nice compact arrangement at the center, as it will cause convection. The output coil should be large and openly-spaced, to gather heat from all over within the tank (don't want to create localized "cool" spots, as they won't convect as easily, and may linger near the coil). I wouldn't suggest a top and bottom arrangement, unless the tank is low and flat. I'm assuming from your dimensions that the 7-feet is the height. In that case, I would suggest concentric coils, with the input coil in the center and the output coil around it. Figure the diameter of the output coil to be 2/3 the tank diameter (assuming a round tank - obviously yours is not, but diameter is an easier way to describe it), and the inner coil to be about 1/3 the tank diameter. The stratification of the tank still comes into play, so you don't want place them evenly. The input coil should extend from the bottom to about 2/3 of the way up, and the output coild should extend from the top to 2/3 of the way down. You want to create flow, to keep things even, so you want to avoid adding heat to the top third of the tank, and removing it from the bottom third - the imbalance will create nice currents within the tank.

If you do a "spiral" sort of layout (relatively horizontal tubes, as opposed to relatively vertical tubes), plan on having the input coil flow down, and the output coil flow up. Since this will put the coolest part of the coil near the coolest water in the tank, heat transfer will be enhanced. I would probably type up some more, but I think dinner is ready...

Joe
Brownian Heating Technology

 

[slowzuki]

Just caught this discussion now, my input on the gasification is if you replaced the fire at the heat input to gasify the wood, can it still burn at the nozzle? The fan is a really important component for the control reasons stated earlier. A chimney can't produce a consistent draft for the combustion and could result in positive feedback on fire size leading to overheating.

 

[Tommy2balls]

Hooked up my refurbished Blue Forge last Saturday and love it. There is no better way to demonstrate gasification then putting two hay bales into the huge fire box.