# Can someone explain a hybrid stove to me?



## jeffesonm (Oct 4, 2012)

As mentioned over here, I've narrowed down my search for an insert to the non-cat Osburn Matrix and the catalytic FPX Large Flush Wood Hybrid-Fyre.  Primary differences are price, firebox size (maybe), aesthetics and cat/no cat.  I went back and read about fifty cat/no cat threads so no need to beat that dead horse.

The FPX stove is advertised as a hybrid model... can someone explain that?  Is it just a fancy advertising term for catalytic?  Does the bypass mean you can run it as a non-cat?  Something else?


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## fire_man (Oct 4, 2012)

I'm only familiar with the term "Hybrid" as it pertains to the Woodstock Progress Hybrid Woodstove.This is what Woodstock says. Hope it helps!

*What do we mean by Hybrid?

Hy-brid* (noun): A thing made by combining two different elements; a mixture. Hybrid is a word that is being used more frequently these days. Auto makers are building hybrid gas and electric cars that increase fuel economy. Biologists have created hybrid crops that are more resilient and grow quicker. The marriage of two different technologies or ideas can lead to a product that captures the best parts of its different components. So what exactly is the Woodstock Soapstone Progress Hybrid? What elements have been combined that make this a superior wood stove? These are questions we are asked every day.

The Progress is a true hybrid because it combines a catalytic combustor with a secondary combustion system. Each of these elements is used to reduce wood stove emissions and increase efficiency. Until now, wood stoves have been using either a catalytic combustor or a secondary combustion system to meet EPA emissions standards. Each design is capable of meeting the standards by itself, so why go to the trouble and expense of developing a wood stove that combines these two separate systems? The answer lies in the way each system performs best. A catalytic combustor has the ability to break down the compounds in wood smoke at temperatures as low as 500 degrees F. This allows for more complete combustion (less pollution) at a low to moderate burn rate. The catalytic reaction produces a considerable amount of heat from the wood smoke as well producing a long, clean, and efficient burn. A secondary combustion system requires much higher temperatures ( over1000 degrees F) to break down the same compounds in the wood smoke. These systems work most effectively at higher burn rates. The idea behind combining these two different systems in one wood stove is to capture a clean and efficient burn throughout the entire burn range. 

Seems simple, right? The real trick is getting the two different systems to work effectively together and make the stove as simple to operate as possible. Through the long and winding path of R&D we have designed an air damper system that controls both primary and secondary air to the firebox using a single, simple lever. The ratio of primary to secondary air is pre-set so the user does not have to fiddle with separate knobs or levers to fine tune the burn. The Progress will automatically deliver unused secondary air to the combustor at lower burn rates, or allow the air to combine with gases in the firebox at higher burn rates for a spectacular secondary burn. At a medium burn rate, the secondary flames and catalytic combustor alternate depending on the conditions in the firebox. Two different systems, working in harmony, make the Progress Hybrid.


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## Huntindog1 (Oct 4, 2012)

Thats pretty impressive .58 grams per hour emissions as listed on that website. But I just dont understand how the stove has a .58 rating and only be around 80% efficient. Might be because its an insert.
As in maybe not getting the heat out into the room as good as a free standing stove.

I would like someone to explain how grams per hour emissions is related to efficiency ratings?

Seems like they dont track each other very well.

The implication of hybrid technology as described on that website is that first some of the smoke is burnt by the secondary air tubes in the top of the stove and whats left is sent thru the cat to be cleaned even further. For a even cleaner burning stove.

I brought this up on a Wood Stock Progress Hybrid post about their stove , its good to see this website backing up my explanation.

Here is what I wrote previously as a little more indepth:

*I too have wondered what the benefit of hybrid technology is, its a very interesting concept but to actually know what the real world applications of it are would make it more appealing.*

*Just tot take a stab at it here, I would think since the stove gets a higher efficiency rating, that what could be going on is that when the stove is in a mode that the secondaries are firing that a certain amount of the smoke is being re-burned. Now we now nothing is perfect so even with the secondaries lit off and burning that not all the smoke is being used up. We also know that the cat works at a lower level of temp than the secondary burn tubes or manifold mode of operation. So its fair to say that if you got secondaries firing then the cat is also at a temp that it is also operating. I suspect that the cat is cleaning up what is left from the secondary burn manifold mode of operation. It might be said that secondary burn technology by its self is not perfect and it can be said Cat technology by its self is not perfect. But operating together with the secondary burn technology first cleaning up the smoke gases as good as it can then letting the Cat technology clean up an extra amount that's left over , then your left with a cleaner more efficient burning stove. Could it be that the cat works better in this mode if its receiving exhaust from the stove that has been first partially cleaned up with a secondaries firing mode of operation. It would take some lab experiments to see.*

*I see too that part of the hybrid technology is that a person can enjoy the best of both worlds as in shutting the air down low its a full cat mode or opening the air back up the secondaries light off and you get to see the light show.*

*As far as burn time goes maybe it was determined that the 14-16 hour burn time was a happy medium, its plenty long for an overnight burn or a long days work. But also the stove is tuned for best operation.*

*So lastly I do night have the stove or ever operated the stove but what I said above is my best guess as to the mystery every one is asking about as to what Hybrid technology ,what it can do for the real world.*


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## begreen (Oct 4, 2012)

A hybrid stove combines technologies for cleaner burning. Typically this means the stove has both a catalyst and a secondary burn system using burn tubes or other secondary air system.


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## jeffesonm (Oct 4, 2012)

Thanks.

I just read a bunch of threads on the Woodstock Progress... sounds like everyone agrees unanimously they are a revolutionary new stove design that far surpasses non-cat and regular cat stoves.  Or that they're an overpriced, complicated setup that provides a marginal reduction of emissions and negligible increase in performance, and that you may as well just get a non-cat stove. 

Anyone else make a hybrid?  The FPX/Avalon model is still pretty new so tough to find feedback on that one.


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## Dairyman (Oct 4, 2012)

Lopi and Regency have new hybrids as well.

http://www.lopistoves.com/product_guide/detail.aspx?id=364#Specs

http://www.regency-vision.com/product-f5100.php


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## slindo (Oct 4, 2012)

I don't get it. A cat is by definition a secondary burn. I can't really see the difference between these so called hybrids and the old cat VCs which had a separate air system to feed the after-cat combustion chamber. Oh, and if they really are adding yet another separate stage of combusion stage, then wouldn't it be tertiary?

Still, not as nutty as the 2-in-1 VCs where you have both systems, but don't use them at the same time. Guess it functions as an opt-out, for when owners get tired of paying for new cats.


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## BrowningBAR (Oct 4, 2012)

slindo said:


> I don't get it. A cat is by definition a secondary burn. I can't really see the difference between these so called hybrids and the old cat VCs which had a separate air system to feed the after-cat combustion chamber. Oh, and if they really are adding yet another separate stage of combusion stage, then wouldn't it be tertiary?
> 
> Still, not as nutty as the 2-in-1 VCs where you have both systems, but don't use them at the same time. Guess it functions as an opt-out, for when owners get tired of paying for new cats.


 
There are no similarities between Woodstock's hybrid and VC's cat system. Even with my complaints about Woodstock's hybrid system, it is still better than the old or new VC cat design.

Also, the point of the VC cat design is that you have the option to burn in the non-cat "Everburn" burn mode that does not require a Catalyst or to burn in Cat mode.

This would allow people like the OP to burn the stove even after they fry their cat.


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## BrowningBAR (Oct 4, 2012)

jeffesonm said:


> Thanks.
> 
> I just read a bunch of threads on the Woodstock Progress... sounds like everyone agrees unanimously they are a revolutionary new stove design that far surpasses non-cat and regular cat stoves.


 
Not necessarily. The hybrid design, at this point, seems to be different than non-cat and cat stoves. But not necessarily better, as it depends upon your needs.



> Or that they're an overpriced, complicated setup that provides a marginal reduction of emissions and negligible increase in performance, and that you may as well just get a non-cat stove.


A Blaze King Prince or King will still set you back just as much, if not more, than the Woodstock Progress Hybrid. Over-priced is determined by what you can afford and what you are looking for in a product.


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## slindo (Oct 4, 2012)

What is called a "limp home" mode in automotive circles. I have always been a bit suspicious of manufacturers who spend too much time boasting about backup systems. I'd think VC might have been more profitably engaged in designing a stove that wouldn't fry its cat, rather than one that could still be used when it did.



BrowningBAR said:


> This would allow people like the OP to burn the stove even after they fry their cat.


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## BrowningBAR (Oct 4, 2012)

slindo said:


> What is called a "limp home" mode in automotive circles. I have always been a bit suspicious of manufacturers who spend too much time boasting about backup systems. I'd think VC might have been more profitably engaged in designing a stove that wouldn't fry its cat, rather than one that could still be used when it did.


 
It's not a backup system. It is an either/or design. Without the cat it runs like VC's Everburn stoves. What VC did was allowed the stoves to be used as either a Cat stove or as an Everburn stove, which simplified their parts and model line, which was a mess previously.

All stoves can fry their cats if operated poorly. Whether it is a VC, Woodstock, Blaze King, or whomever, the drayback of cat stoves is that the stove owner must be more educated on how to run a stove. Most stove owners just want to throw wood into a firebox and walk away.

If you do not monitor your cat temps, you will destroy your cat in a short period of time no mater who manufactured the stove.


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## Dairyman (Oct 4, 2012)

slindo said:


> What is called a "limp home" mode in automotive circles. I have always been a bit suspicious of manufacturers who spend too much time boasting about backup systems. I'd think VC might have been more profitably engaged in designing a stove that wouldn't fry its cat, rather than one that could still be used when it did.



I don't think thats the purpose of the hybrid. At least in woodstocks case their trying to impliment the best of both desines.


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## slindo (Oct 4, 2012)

BTW I just noticed that VC refers to its 2-in-1 ones as being "three stage" and "creating heat three times". That sure sounds like a hybid, unless they really mean "Creates heat three times (but not simultaneously)".

Odd thing about the 2-in-1, VC used to have some of the best sales literature in the business , but there is nothing I can find about how the 2-in-1 actually works. No schematics or diagrams. Not even a picture of one with the door open! Or am I looking in the wrong place?


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## BrowningBAR (Oct 4, 2012)

The VC is not a hybrid. You are simply reading fancy market verbiage. The VC stoves are an either/or design. You physically have to remove the cat in order to switch to the Everburn mode.

If you search on YouTube you will find a video that was posted showing how the system worked and why it was done during a VC dealer convention. Their cat system, though improved, is still a distant third behind Woodstock and Blaze King.


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## Highbeam (Oct 4, 2012)

Thus far the hybrid stoves have only been a standard non-cat tube tove with further emission reductions by adding a cat. You do NOT get the best of both worlds. You get to replace cats, and you can't burn low and slow. Sounds to me like the worst of both worlds.


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## corey21 (Oct 4, 2012)

Highbeam said:


> Thus far the hybrid stoves have only been a standard non-cat tube tove with further emission reductions by adding a cat. You do NOT get the best of both worlds. You get to replace cats, and you can't burn low and slow. Sounds to me like the worst of both worlds.


 
I agree Having burn tubes in a cat stove would take away from the slow and low burn of a cat stove that i hear about.


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## Waulie (Oct 4, 2012)

Highbeam said:


> Thus far the hybrid stoves have only been a standard non-cat tube tove with further emission reductions by adding a cat. You do NOT get the best of both worlds. You get to replace cats, and you can't burn low and slow. Sounds to me like the worst of both worlds.


 
It does, too a point.  But, since you keep saying it, I'll keep saying that the PH hybrid system does allow me to burn in all cat mode, low and slow on up to about 60% loads.  So, it's like having two stoves.  One, a cat stove about the size of the Fireview and the other, a large secondary stove with higher effficiencies than typical secondary stoves.  This is great for me, but not great for people who want 20+ hour burns.


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## slindo (Oct 4, 2012)

Found a YouTube video with a Scotty Jackson explaining the system. Is that the one?

Kind of weird, he spent longer showing off the oval p[pe adaptor than explaining how the 2-in-1 system worked. He said that their were tow modes, through the cat, or "straight up" for livelier flames or use in open fireplace mode. No mention of secondaries, Everburn or any high efficiency non-cat mode. Sure sounded  like he was talking about the old  straight up the chimney setting all VCs have all had since year one. So it appears that either Scotty or the VC advertising people don't have a clue how the stove works, or there is considerably less to  2-in-1 than VC would have us believe. Oh well it wasn't as if I was going to buy one anyhow, but as an old VC owner from the picnic-and-newsletter days I keep hoping they will pull it together and make a good stove again.

Think maybe I'll swing by Woodstock tomorrow and get a good look at their hybrid.



BrowningBAR said:


> If you search on YouTube you will find a video that was posted showing how the system worked and why it was done during a VC dealer convention. Their cat system, though improved, is still a distant third behind Woodstock and Blaze King.


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## Huntindog1 (Oct 4, 2012)

Slindo, here is a pic for you to study of the Wood Stock Progress Hybrid (is that a double pane front glass? Oh I guess it says it is..)


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## Highbeam (Oct 4, 2012)

If I was going to get into a hybrid stove it would certainly be the PH. I trust the WS engineering over any of the hybrid competition. It would be a great stove for the real cold times where you need medium to high output.


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## Huntindog1 (Oct 4, 2012)

Looks like from that pic and some you tube videos. Looks like alot of design went into keeping that glass clean and still having enjoyable flames to view thru a clean glass at the stoves lowest settings. Look at the pic how the primary air wash air travels all the way around the stove picking up heat plus the air wash primary air manifold above the window is large and the window is double pane to keep the inside of the glass from cooling thus keeping the heat up on the surface of the inside of the glass thus keep it cleaner.

This design would take away from a longer burn time as it seems like the design objectives were a little different.


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## Huntindog1 (Oct 4, 2012)

Not sure what the stoves settings are here but for a cat burn level like it says those are alot of flames but the glass is really clean. Can the stove lower down to hardly any flames? Can anyone with a Progress Hybrid tell us if it will go lower than this video. This video is described as a PH in cat mode.


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## FyreBug (Oct 4, 2012)

Huntindog1 said:


> I would like someone to explain how grams per hour emissions is related to efficiency ratings?
> Seems like they dont track each other very well.


Efficiencies and low emissions are a bit related because of unburned fuels being emitted as pollutants, however...even a clean burning stove can have lower efficiencies if there is a lot of heat loss up the chimney. There are two different efficiencies...Combustion efficiency...and heating efficiency. Most efficiencies rate you see are "heating efficiencies". That is if a pound of wood is worth 8,200 BTU and you lose 20% of it in the flue required for drafting (stack loss) your overall efficiencies will obviously be at 80%. 

What you try to do is to have as hot as possible a combustion chamber since burning at higher temp provides a cleaner combustion while keeping your stack temp as low as possible. It's a real balancing act. Think of it as a carburator, you can burn lean or rich and it will affect the overall performance of the unit.

That being said designing a stove is part science, art, gut feeling, experience and some voodoo magic!


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## begreen (Oct 4, 2012)

Highbeam said:


> Thus far the hybrid stoves have only been a standard non-cat tube tove with further emission reductions by adding a cat. You do NOT get the best of both worlds. You get to replace cats, and you can't burn low and slow. Sounds to me like the worst of both worlds.


 

I'm watching the Lopi Cape Cod. Travis is no small potato. They engineer good products and the design features they've put into this big stove are nicely done. It will be interesting to see how they perform in hearth.com homes.


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## Waulie (Oct 4, 2012)

> Not sure what the stoves settings are here but for a cat burn level like it says those are alot of flames but the glass is really clean. Can the stove lower down to hardly any flames? Can anyone with a Progress Hybrid tell us if it will go lower than this video. This video is described as a PH in cat mode.


 
I think that video was in their blog during stove development, and the definitely did some tweaking since then.  The PH can be turned down to hardly any/no flames to a certain load level.  For me, it's around 60% full.  Others have reported getting it on a full firebox, but I'm not thrilled with the method used to get it to do that.  At a certain load level, the secondaries take over for awhile, but on a low setting there usually aren't many primary flames after getting the stove up to temp and turning it down.


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## Waulie (Oct 4, 2012)

begreen said:


> I'm watching the Lopi Cape Cod. Travis is no small potato. They engineer good products and the design features they've put into this big stove are nicely done. It will be interesting to see how they perform in hearth.com homes.
> 
> View attachment 75961


 
That is interesting.  The system looks very similiar to the PH, (as do the emissions and efficiency), but I wonder if the user experience will be the same.  Someone buy one!


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## BrowningBAR (Oct 4, 2012)

begreen said:


> I'm watching the Lopi Cape Cod. Travis is no small potato. They engineer good products and the design features they've put into this big stove are nicely done. It will be interesting to see how they perform in hearth.com homes.
> 
> View attachment 75961


 
It's a little surprising that the Cap Cod has the same burn time as the Liberty with about the same size firebox. It isn't doing much to disprove the theory that these hybrid stoves functions like cleaner burning non-cat stoves than they do a cat stove. Which is neither go or bad, it just is.


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## Treacherous (Oct 4, 2012)

Waulie said:


> That is interesting. The system looks very similiar to the PH, (as do the emissions and efficiency), but I wonder if the user experience will be the same. Someone buy one!


 
Looks like efficiency is about the same but Cape Cod has an edge on emissions.

.45 gm/hr versus 1.33 gm/hr with Progress Hybrid


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## Todd (Oct 4, 2012)

I'd still like to see these hybrids tweaked so you can burn them either way. Some way to switch off the secondary burn when you want a 24 hour smouldering cat burn or switch it back to non cat for those colder days. Doesn't seem that hard to do, it's all about the air. 

By the way Blaze King claims they built the first hybrid back in the mid 80's, wonder why they didn't persue it?


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## Todd (Oct 4, 2012)

Treacherous said:


> Looks like efficiency is about the same but Cape Cod has an edge on emissions.
> 
> .45 gm/hr versus 1.33 gm/hr with Progress Hybrid


 
Do we know if that .45 gph number is the average over the whole series of EPA test burns or just the lowest they came up with? I know most straight cat stoves burn that clean in the low burn tests but get dirtier at higher burn rates.


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## BrowningBAR (Oct 4, 2012)

Todd said:


> I'd still like to see these hybrids tweaked so you can burn them either way. Some way to switch off the secondary burn when you want a 24 hour smouldering cat burn or switch it back to non cat for those colder days. Doesn't seem that hard to do, it's all about the air.


 
Agreed, but as long as it could be done on the fly since secondary burning is technically more efficient at higher temps than a cat only burn. Because the way VC has their 2-in1, you have to remove the cat to change over to a non-cat burn.


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## Treacherous (Oct 4, 2012)

From this link

"The Hybrid Fyre™ flattens the emission curb which means all four
burn rates are significantly less than 1 gram per hour. As i
comparison, a typical non-cat emission curve starts dirty at lowburn, cleans up in mid-burn and emissions increase in the highburn rate creating a U-shaped emission curb. A typical catalytic
emissions curb starts lower and increases as the burn rate gets
higher. The Hybrid Fyre tm also reduces the carbon monoxide
level in all burn rates to less than 1/10th of a percent therefore
giving us a combustion efficiency over 95% (using the B 415 test
method). Overall efficiency at all burn rates is in the high 80
percentiles. As an example the overall efficiency during medium low burn is 89.6% (B 415)"


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## fire_man (Oct 4, 2012)

Huntindog1 said:


> Not sure what the stoves settings are here but for a cat burn level like it says those are alot of flames but the glass is really clean. Can the stove lower down to hardly any flames? Can anyone with a Progress Hybrid tell us if it will go lower than this video. This video is described as a PH in cat mode.


 
This does look like a low burn to me. Those are not secondary "jets", they are dancing flames and some firebox smoke burning. Even with the Fireview (a "True" cat stove), firebox temps would eventually climb high enough to light firebox smoke and take some of the work from the cat. I think people are mistaking thinking a black firebox (no flames) is the only way to run in cat mode.

I can't speak for BK stoves, but with my Fireview, the firebox eventually got hot enough to fill the box with rolling flames. That's what's happening in the Video. Maybe that's how BK gets the really long burns, they keep firebox temps low enough on the slow burn that you never light up the firebox smoke. So does that mean the Fireview is not really a "cat only" stove?

True "Secondary mode" happens when the baffle plate lights up like a barbecue grill.Then you see jets of lit smoke darting below the plate.


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## Todd (Oct 4, 2012)

Treacherous said:


> From this link
> 
> "The Hybrid Fyre™ flattens the emission curb which means all four
> burn rates are significantly less than 1 gram per hour. As i
> ...


 
Interesting, that answered my question, thanks.


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## Todd (Oct 4, 2012)

fire_man said:


> This does look like a low burn to me. Those are not secondary "jets", they are dancing flames and some firebox smoke burning. Even with the Fireview (a "True" cat stove), firebox temps would eventually climb high enough to light firebox smoke and take some of the work from the cat. I think people are mistaking thinking a black firebox (no flames) is the only way to run in cat mode.
> 
> I can't speak for BK stoves, but with my Fireview, the firebox eventually got hot enough to fill the box with rolling flames. That's what's happening in the Video. Maybe that's how BK gets the really long burns, they keep firebox temps low enough on the slow burn that you never light up the firebox smoke. So does that mean the Fireview is not really a "cat only" stove?
> 
> True "Secondary mode" happens when the baffle plate lights up like a barbecue grill.Then you see jets of lit smoke darting below the plate.


 
My experience so far is the BK looks to be throttled down a bit more than the WS. Maybe the BK t-stat has something to with it? One difference I noticed is the air wash plate on the Woodstocks have holes which feed some secondary air which may cause some of those nice ghoastly floating flames at those lower burns while the BK doesn't have those holes and the fire box seems to stay dark.


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## Huntindog1 (Oct 4, 2012)

Treacherous said:


> The Hybrid Fyre tm also reduces the carbon monoxide
> level in all burn rates to less than 1/10th of a percent therefore
> giving us a combustion efficiency over 95% (using the B 415 test
> method). "


 
How does a stove lower Carbon Monoxide?

Then I am guessing that the lowering of carbon monoxide leads to a higher efficiency burn due to maybe more oxygen less carbon monoxide.

I said I was guessing 

Ok found my answer online:

_*The less complete the burning (combustion), the more carbon monoxide is generated  ... gas and oil furnaces, fireplaces, and wood stoves all generate carbon monoxide.*_


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## rideau (Oct 4, 2012)

Huntindog1 said:


> Not sure what the stoves settings are here but for a cat burn level like it says those are alot of flames but the glass is really clean. Can the stove lower down to hardly any flames? Can anyone with a Progress Hybrid tell us if it will go lower than this video. This video is described as a PH in cat mode.




Waulie's post, plus if you listen to Tom M talking on that video, he specifically states that they have not turned the air supply down enough to get a 12-1 hours burn, that witht he air setting they have in that viseo they will get an 8 - 10 hour burn...So, yes, you can turn the air down for a slower, longer cat burn.  Easily.


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## Huntindog1 (Oct 4, 2012)

Yes I turned the sound up and I do hear that now thanks.

He said he can turn it down even lower to get  a 12-15 hour burn.


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## begreen (Oct 4, 2012)

Waulie said:


> That is interesting. The system looks very similiar to the PH, (as do the emissions and efficiency), but I wonder if the user experience will be the same. Someone buy one!



If Travis is willing to supply, I am willing to try and report.


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