VF100

[Mellowyelloe]

Ok I just saw an ad on here for the vf100. It's not a boiler, it's a furnace. So I assume it provides heat on demand. Also it has no storage I believe.

So what I would like to know is how it burns on and off but yet is still so efficient.

My homemade gasifier that I made(shared in my previous post) was originally going to be a boiler, but after seeing the VF100, I'm toying with the idea of making it a furnace. But I can't load it every hour or two. I'm just wonder how they are controlled.

Thanks for any insight.

 

[Jgib4]

They have a thermostat you can set. Mine pretty much blows continuously otherwise the air heats up to much and runs me out of the house. You obviously have to keep some type of fuel in it burning or the temp in the house will go down.

 

[Mellowyelloe]

I'm sorry I guess I should clarify. I'm wanting to know how the firebox is vented and controlled.

Gasification is generally referred to as fast and hot. I'd like to know what method they use for a slow burn that produces gasification.

 

[maple1]

I think it's 'just' mainly careful regulation of primary & secondary air. All done automatically via computer control.

Stepping back a bit, it is possible to choke down & smolder an 'ordinary' wood burner by shutting down its air supply. That smoldering isn't what you really want - the wood eventually will go up the stack in smoke & creosote. But if you can burn it secondarily at the rate it is being generated, then you get a slow clean burner. So maintaining combustion heat where the secondary is taking place would also be key - firebox design & insulation effects coming into play.

Tubular wood stoves can get a fairly long burn (maybe not as long & low & slow as a cat stove) - I think same basic idea but just on a bit bigger scale and better controlled & regulated. Also a furnace isn't hampered by the liquid cooled box that a boiler has.

 

[Highbeam]

Gasification does not have to be fast and hot.

 

[STIHLY DAN]

It is also not slow and low..... load size is key.

 

[Mellowyelloe]

Well then, can you all possibly elaborate on the methods? I would prefer to build me a gasification furnace like the vf100 but my concept of gasification is obviously skewed a bit.

My research continues.

 

[maple1]

I have never even seen a VF100 in person so can't elaborate much more. But the key elements to me would be keeping lots of heat where the secondary burn is happening (insulation) as well as retaining the gasses there long enough for them to burn (chamber design), and being able to fully regulate the air coming into both the primary and secondary burn areas, independently of each other. How much air gets in the primary will determine how fast the gasses get sent to the secondary, how much air gets sent to the secondary will influence the quality of the secondary burning. Another thing that helps in the boiler world is if the gasses can pass through a coal bed on their way from primary to secondary - maybe not as important if not dealing with a liquid cooled firebox.

 

[brenndatomu]

The VF100 is computer controlled/regulated...but much of the magic is just good firebox design IMO. If you want to copy it, good luck...I'd bet there are a dozen multi-million dollar/yr wood furnace manufacturers with a VF100 sitting in their R n D dept right now while they try to figure out how to get their furnaces to pass the EPA's 2020 test like Kuuma has.

 

[Mellowyelloe]

Getting the certification is just a formality. Kuuma just decided to pay for it all already. Other manufacturers haven't spent the time and money yet to get certified. Another possibility is that they haven't released their models that pass the 2020 regs. Multi million dollar companies are not going to sit around and lose their business due to regulation's they knew about years in advanced.

But yes I'm sure every wood heating appliance manufacturer has a vf100 sitting in a room along with 100 other furnaces and boilers from various manufacturers. And I'm sure kuuma has a few kicking around somewhere too.

Anyways to refocus. I know it's computer controlled I know I could buy one and copy it. But why copy it if I already have one.

I've looked for pictures and videos of the vf100 during operation and can't seem to find any. Heck I can't even find a picture of the inside at all.

I'm just wondering is updraft, downdraft, sidedraft, cyclone, swirly, curly Q. You know, the method to the madness as some might say. I understand the airflow is commuter controlled. But the physical box is not.

If I got the Dynamics of it down I could figure out the air flow control. May not be as precise but it will still work.

 

[brenndatomu]

Multi million dollar companies are not going to sit around and lose their business due to regulation's they knew about years in advanced.

Its already happened...the number of wood furnace manufactures is down to single digits...a few years ago there were a couple dozen.

Getting the certification is just a formality. Kuuma just decided to pay for it all already. Other manufacturers haven't spent the time and money yet to get certified

Why would they not just go ahead and get the 2020 certification if they could pass it...the test is very expensive, pretty silly to pay for it twice if you don't have to.

And I'm sure kuuma has a few kicking around somewhere too.

I highly doubt it, why would you study something inferior to your product? Also, they don't have to room to waste on things like this...they have a very small facility (for now, new digs coming soon)

 

[brenndatomu]

Gasification does not have to be fast and hot.

It does not have to be fast...but it does have to be hot, at least a minimum to keep the secondary fire going...and if it starts to die off, the computer will open the damper for a bit to build the temp back up.

 

[Mellowyelloe]

Why would they not go ahead and get the 2020 certification if they could pass it...the test is very expensive, pretty silly to pay for it twice if you don't have to.

Why don't car manufactures release all the tricks up their sleeves. Because others would copy it, plus then the govt. would enact even more strict CAFE standards.

Why doesn't the military openly use all their high tech secret weapons. Because others would copy them and they'd have to scramble to come up with something better.

Business is like playing poker, you don't let everyone see your cards until it's all over.

Believe me if I can't recreate a downdraft gasifer, having never seeing one in person, only seeing pictures and diagrams of the basic principles of how they work. Then a business whose livelihood depends on it can reverse engineer a $6,000 furnace. And if they can't then they were on they're out already. I would assume why so many manufacturers went out was because they didn't have the capital to retool their facilities, not because they couldn't design a firebox to meet standards that are obviously completely possible.

But hey I could be wrong.

 

[maple1]

If you can't get eyes on a Kuuma for study or get their design spelled out on here, there are other clean burners out there you should be able to get up close & personal with by visiting a dealer display or showroom.

Why the fixation on Kuuma? They are apparently the cleanest but there are others that are almost as clean. Without a computer. Or maybe they are just as clean? Since you seem to say (I think) that they might be but just don't want to pony up the certification $$?

Tundra, Caddy...

I suspect the reason some others have dropped out was because they sat for years on their old tech, vs. Kuuma steadily investing in R&D over the years to improve theirs. They invested in themselves. Then when the standards (that could be seen coming for years) hit the fan, the others were faced with a mountain of R&D investment to come up with all at once (plus $$ for certification testing) - or get out - at which point they decided to bail. Whereas Kuuma was investing a bit at a time for years getting themselves ahead of the curve. If the others had had the tech down they should have been able to prove that to investors or their financiers to secure tooling funding. Tooling funding should have been the easy part - getting the engineering & design part down to justify the tooling cost would have been the biggest hurdle, IMO.

 

[woodey]

Business is like playing poker, you don't let everyone see your cards until it's all over.

Yes ,and maybe other manufacturers are not showing their cards knowing that they have a losing hand and their idea of poker is betting that the EPA will suspend the 2020 standards so that they will be able to sell their product w/o having to spend $$$ on R&D. Good luck with your project.

 

[Highbeam]

It does not have to be fast...but it does have to be hot, at least a minimum to keep the secondary fire going...and if it starts to die off, the computer will open the damper for a bit to build the temp back up.

Both fast and hot are obviously relative terms. In this application there is a range of possible speeds and temperatures that result in sufficient “gasification” and clean burning. I shouldn’t have to write that out but it seemed to cause confusion otherwise.

Efficiency and low emissions are not directly related. The kuuma isn’t as awesomely efficient as it is awesomely clean. That’s the accomplishment, very clean with pretty good efficiency. Very expensive though.

 

[TCaldwell]

Your where I was 10 years ago in the combustion control, however I modified a boiler and you are building one. The concepts to combustion control for gasification are the same regardless of boiler/furnace, however the methods differ due to the different combustor designs that each manufacturer employs, what you are asking for with regards to kuuma is proprietary, and results would differ with their controller on your boiler.
I’m not trying to discourage you, rather I applaud your interest.
Basically combustion control of a batch of wood is based on maintaining a residual amount of o2in the fluestream after the process, for wood it varies by combustor from 3 to 8 percent, of course secondary burn must be maintained regardless. 0 percent o2 represents a stiochometeric value, all wood consumed with no oxygen left, however all combustors need excess air to function, hence the 3-8 pct, for instance I run at 5 pct, that equates to 30 pct excess air. Theoretically with a batch of wood, you are retarding the fire to begin with and as the wood load depleats you end up forcing the fire torwards end.
This is accomplished with a o2 sensor in the fluestream providing data to a pid controller witch in turn provides a output to a primary and secondary damper to control air flows.
This example is a simplification, but hopefully you get the idea.

 

[Mellowyelloe]

Yes ,and maybe other manufacturers are not showing their cards knowing that they have a losing hand and their idea of poker is betting that the EPA will suspend the 2020 standards so that they will be able to sell their product w/o having to spend $$$ on R&D. Good luck with your project.

Ah, hadn't thought of that. Me being me would not bluff though. Don't like running risks when it comes to money. Lol. And thanks.

And highbeam. In the last few days I have come to realize what you state about the possible speeds and temperatures. Which has made me realize I have a lot of trials still to go.

 

[Mellowyelloe]

Wow tcaldwell. I do get an idea. I get the idea that I would love to pick your brain a lot. Not sure I even know where to begin.

What kind of boiler are you using? Downdraft or updraft or what. Where in the flue stream is your o2 sensor. Do you use an o2 sensor from a car or a specialty one. What kind of pic do you have. The one I have, I don't believe would be able to what you're describing.

Thanks for any help and information.

 

[TCaldwell]

Phone numbers are on my profile page