EPA taking another look at standards

[WoodMann]

Great article, thanks for the link. operator instruction would certianly go a long way. But are we then going to see mandatory apptitude tests to have a stove, seems like it would be a good idea alot of the time with many other things as well, but let's keep Big Brother at bay.............

 

[gyrfalcon]

Woodstoves have two problems. The wood that goes into the stove, and the people that place that wood into the stove. The "EPA" certified stove has partially taken the 'people' problem out of the mix by ensuring that a minimum volume of air gets into the device to properly combust our good friend, "seasoned wood".

Which leaves the first problem - the wood that goes into the stove. Well, guess what, the EPA is monitoring the wrong industry. Good fuel in an inefficient device will burn cleaner than bad fuel in an efficient device. If the "G-man" were to regulate anything, my take is that it would be the folks who split, measure, and deliver our fuel to us. "Seasoned" should mean just that - it's been seasoned and is ready to be burned efficiently in today's technological catalytic secondary burning marvels. Of course, the downside to "regulating" our friendly neighborhood cordwood seller is that his prices will be higher. But the upside is that our fuel should be better, and a cord should (gasps) actually be a cord? Really? Perish the thought!

The pellet stove industry hit a home run because they created an easy to use appliance (load and go) and an entire fuel industry was built to support it. By design, they're clean and almost foolproof. As solid wood burners, we can't (affordably) go to the Home Depot and buy 50 pound bags of cordwood. Instead we have to rely upon sometimes less than reputable cordwood sellers and we've all heard the stories.

Of course there's the bio-fuel industry (ie biobricks and their kin). Clean, consistent, convenient, and sold by weight, not by volume. I've been running these all winter. A warm house, clean chimney, and not a hint of smoke once things are up to temp in my Kent Sherwood. Compare that to the guy at the end of my street who is spewing smoke literally on a 24x7 basis.

Well, just my honest opinion.

Cheers

It's a darn good opinion, except that the feds are never even going to try to regulate firewood suppliers, nor would we want them to. (Gah! What a horrible thought!) Even state governments are unwilling to do more than write a few regulations down on paper for the record.

But I actually don't think the price of firewood would go up if it happened, you'd just end up with terminology that reflects reality. Very, very, very few folks who deal in firewood have room or labor to actually keep stacks of cut and split wood of various sizes hanging around for a couple years worth of drying no matter what. But it sure would be nice if they could all be persuaded to use standard terms with standard definitions-- seasoned, semi-seasoned, semi-green, green. Or something. And 99 percent of what gets sold would still be in the semi-green and green category, which would be fine because then at least everybody would know what they were getting.

Short of regulatin', though, what has worked in some other industries is some kind of industry monitoring group that does occasional inspections and gives out "seals of approval" or certifications or something. Then at least the new burner would have at least a hint that buying "seasoned" wood from somebody who doesn't have that certification or seal of approval is unlikely to get what they're looking for. Same with actual cord size.

I actually think if I were a stove dealer, I might look into making some sort of deal with the local kiln-dried firewood operation to offer a good discount on a first cord of firewood for my new stove buyers.

 

[precaud]

I think they're going to have difficulty forcing anything beyond the Washington state 4.5gm/hr emissions level. Surely they are aware that this program has been a huge success, and has created a wide variety of stove designs that burn cleanly. They don't want to kill that diversity.

Switching to cordwood for test fuel will be a good thing imo, though it WILL eliminate some current models from compliance. I guarantee you that the Jotul F602 CB will not pass even the current limit when loaded with real fuel. I'm sure there are others too.

Something I'd like to see changed: Require manufacturers to publish more complete info from the tests, especially related to the maximum output rate. It's the most misleading spec of them all, because it does not specify the amount of time the stove is capable of sustaining that rate of output. But add the length of time the stove sustains that output rate (within a certain percentage) and then you have real useful info that can be compared to other stoves.

 

[precaud]

Oh, and I can't pass up another opportunity to trash cast iron firebox liners, and JG agrees with me:

"As it is, the best manufacturers have improved their designs over the years, so that now a good selection of mainstream non-cats are certified down in the 3 grams per hour range. These low rates have been achieved by using reflective, non-metallic materials in the firebox and by fine-tuning the air supply patterns."

 

[cycloxer]

Oh, and I can't pass up another opportunity to trash cast iron firebox liners

What's wrong with cast iron firebox liners like on the Jotul F 400 Castine?

 

[precaud]

Cast iron is not a good thermal insulator. It resists heat like sponge resists water.

 

[cycloxer]

So why does Jotul line the inside of their stove with cast iron? What should they use instead?

 

[precaud]

So why does Jotul line the inside of their stove with cast iron?

Well that's the question. And the simplest answer is: they use it because they own a foundry and want to make as full utilization of it as possible. There are good reasons why you don't see manufacturers who don't own foundries going out and buying cast iron liners.

What should they use instead?

As the article says, non-metallic insulating materials. There are a good variety to choose from.

 

[precaud]

Your response epitomizes the misunderstanding that prevails about clean combustion technology. There is absolutely no need to "hold heat" for the next fire if the lining is lightweight and has good insulating properties.

 

[cycloxer]

Jotul has proven that you easily design a 75%+ efficient stove with a cast iron firebox. The cast iron is used to protect the fire brick behind the panels. You can beat the crap out of the inside of the stove with your wood with no risk of damage. It adds thermal mass and has the same thermal expansion as the rest of the stove. Finally, it adds an element of design as you can see the cast star and signature in the back panel of the F 400. As the fire burns down, this looks really cool through the glass. I much prefer the full cast iron lined Jotul's for their durability and aesthetics. Whenever I look at a stove with exposed firebrick I feel like I am looking at the inside of an industrial kiln = blech. With a smaller stove like the F 400, you can really cram a lot of wood into the fire box without having to delicately place the logs and worry about cracking, chipping, or wearing your fire brick. That has value, affords ease of use, and adds longevity to the product. This is exactly why you still see pre-EPA cast iron Vermont Castings stoves running today. They were built like battleships.

 

[precaud]

I too love the aesthetic of cast iron stoves. And yes, you can beat the crap out of cast iron liners. But what is this thread is about? It's about the future of clean combustion technology. It seems nearly impossible to discuss this topic on this website without old concepts coming in and confusing the issue. Aren't we mature enough to love our cast iron-lined stoves and yet, at the same time, recognize that the future of clean combustion technology lies in a different direction? I think so. This is not an emotional issue, it's strictly about the properties of materials and how they contribute to the matter at hand. And the fact is, cast iron firebox liners do not and will not play a positive role in furthering the art of clean combustion.

 

[precaud]

That paper is about the basic stages of combustion and not about clean combustion design technology. Some of my previous threads on this topic have good links to information sources.

 

[precaud]

Pat, yes, of course they're linked, but that article focuses on the fuel, not the appliance. I've done several experiments and supplied many links to combustion chamber design in my past threads. Use the advanced search facility, search for "lining material" and posts under my moniker to see them. Wood-burning stoves are not at the cutting edge; they are catching up to and incorporating advances made in other industries.

 

[madrone]

Firebrick is specifically designed for this purpose, to reflect heat and insulate the interior space, in order to achieve higher temperatures with less fuel. If you're looking at efficiency, you're going to choose a refractory material over cast iron. Holding heat is great, but reflecting heat helps reach the temps needed for secondary combustion more efficiently.

My Lopi is around the same firebox size as an Oslo, but puts out 1.9 grams per hour, vs the Jotul's 3.2. Same basic combustion design, but firebrick vs. cast iron. I love the look of the Oslo, and grew up with a knock-off 602. I'm no cast-iron basher, but it's academic if you're talking about efficiency.
P.S. I cram wood in the Endeavor, and the 10-year-old bricks are in great shape. I worry more about the tubes than the bricks.

 

[cycloxer]

The firebox is not the limiting factor of a clean burning stove. This is why Jotul can build a stove virtually 100% out of cast iron and still hit the EPA #'s. The 'technology' (if you want to call it that because all of these modern stoves are still pretty simple devices) is all in the secondary baffles, cats, airflow path, and thermal modeling.

If you want to take stoves to the next level of efficiency and cleanliness, you are going to have to add computer controlled electromechanical systems, air injection pumps, and cats. Look at how car manufacturers design their emmission systems. You could totally do this to a stove btw, but it would drive the design complexity and product cost higher...and in the end you'd still have idiots who would burn green wood and screw up the whole system.

 

[cycloxer]

My Lopi is around the same firebox size as an Oslo, but puts out 1.9 grams per hour, vs the Jotul's 3.2.

There is virtually no difference between those two #'s that were recorded in a lab burning dimensional lumber.

Firebrick is used because it is cheap and effective. Why do you think Englander uses a full fire brick lined firebox with standard sized bricks? The Jotul fireboxes are actually fully lined with fire brick, but Jotul takes the design one step further and adds an additional layer of cast iron panels. The only reason Jotul uses cast iron is because it looks nice and the air voids in the castings provide the soft heat feel.

Yes, you could certainly design a more efficient stove, but I wouldn't want to look at something like my Burnham gas boiler on my hearth. (btw, go check out the efficiency on Burnham's condensing gas units and it will make you drool. Talk about a super-efficient clean burning product. http://burnham.com/products/residential-boilers-indirect-water-heaters ) It will take some time for the manufacturers to creatively package even more complex technology into an attractive design. This is a very important point as customers are putting these products in their living room. How many modern stoves don't have front glass panels? The glass is purely for aesthetics, but it is a very important design feature.

 

[ihookem]

I just don't see how you can have less smoke than my Eko 25. Even when it's not gassifying properly, it hardly smokes. When it gassifies you can't see anything coming out. The only thing we can do is make the smoke go through two gassifiers. I always wondered though if you could put in an electric "glow plug" to make the smoke burn better. I don't know if it's possible but I don't know why it wouldn't work. Seems simple to me, if the temp gets down too far the glow plug goes on. Maybe it would help some. I don't know, maybe your all laughing at me by now.

 

[cycloxer]

That Eko product is very cool. Its major flaw is that you can't turn it on/off quickly as with a gas or oil burner. As a result, sure, you are getting 90%+ efficiency, but you have to run the burner 24/7. So you are going to burn much more fuel.

 

[snowtime]

Well my reaction is to order all the spare parts for all my stoves that i could possibly need for my lifetime. Since we have 6 wood stoves and need them for our lifestyle that makes sense to me.

As far as breaking firebrick we have all done it but I venture that most would stop having any trouble if they loaded NS. Of course some stoves do not lend themselves to this but I noticed the article sang the praises of a box or square stove.

 

[precaud]

The firebox is not the limiting factor of a clean burning stove

Nobody said it was. But it plays an essential role.

The 'technology' (if you want to call it that because all of these modern stoves are still pretty simple devices) is all in the secondary baffles, cats, airflow path, and thermal modeling.

No, it's not ALL in those things. A low-mass, highly insulated environment makes a significant difference. I've done experiments to prove it.

 

[begreen]

The Jotul fireboxes are actually fully lined with fire brick, but Jotul takes the design one step further and adds an additional layer of cast iron panels. The only reason Jotul uses cast iron is because it looks nice and the air voids in the castings provide the soft heat feel.

That is incorrect.

 

[grommal]

Our new Oslo has firebrick in the back. The sides have extra cast iron plates attached on the inside, with insulation between the plates and the cast iron shell. There is still a fair amount of area where the sides meet the back that is not insulated. The floor of the stove is a large cast iron grate to allow ashes to fall into the ash pan. The firebox does not have a firebrick floor. Naturally, the enormous glass door on the front is not lined with firebrick or other insulation.

So, I'd say it's partially lined with a combination of firebrick and insulated cast iron panels. Maybe 50% of the firebox surface, if you count the baffle, the firebricks, and the insulated side panels.

 

[cycloxer]

Okay correction, Jotul uses a combination of cast plates, vermiculate, and insulation blanket depending on the stove model. This further proves that the firebox does not need to be 100% fire brick to achieve the 75% efficiency & < 5 grams EPA regs. It's not where they are getting their biggest efficiency gains. In fact, I bet you could take an old VC cast stove and retrofit a reburn manifold into it and you would hit the EPA #'s. A few people on the forum have actually done this. I can assure you that Jotul is not simply adding cast plates because they own a foundry. The NRE to design, test, and produce a custom casting is not insignificant. It would be much easier to use standard sized bricks as other manufacturers do to keep costs down (Drolet, Englander, etc).

The problem with all of today's stoves is that they don't operate at those published #'s all of the time. The #'s are almost a joke. They were tested in a lab with dimensional lumber. That is not the fuel we use. At start-up and burn-down our stoves are nowhere near as clean as the EPA wants. I don't care how experienced of a burner you are, your stove is dirty as all hell at start-up and as the fuel burns down the stove efficiency drops off significantly. You don't see flames shooting out of the secondaries all of the time. With a cat stove you can only engage the cat when it is at the proper operating temperature and it starts wearing out and losing efficiency from day 1.

Burn a full load of cord wood in a modern stove and then measure the real world efficiency and grams of particulates over the entire burn cycle and publish those #'s.

 

[precaud]

I think we can find some points of agreement here, though I still think you are defending your choice of woodstove rather than discussing the topic at hand.

I can assure you that Jotul is not simply adding cast plates because they own a foundry.

Then show me a stovemaker who does not own a foundry that uses cast iron liners. If it's such a good idea, surely it would be more widely adopted.

The problem with all of today's stoves is that they don't operate at those published #'s all of the time. The #'s are almost a joke.

Totally agree.

At start-up and burn-down our stoves are nowhere near as clean as the EPA wants. I don't care how experienced of a burner you are, your stove is dirty as all hell at start-up and as the fuel burns down the stove efficiency drops off significantly.

Now you're making my point. The beginning and ending of the burn cycle is definitely when the emissions numbers are higher, and this is where the linings have a huge effect. Stoves with a higher percentage of lighter-weight, thermally reflective non-metallic lining will come up to operating temps much quicker, maintain those higher interior temps longer, and burn cleaner as a consequence. It's really just a function of the material's thermal mass and absorption characteristics. Replace the cast iron liners in your Oslo with a better thermal insulator and you'll see (and feel) the difference. There are other benefits to using this material too, but that's another topic.

I want to say again, this discussion is really about future trends, not about defending the past. Jotul is getting picked on because their fireboxes probably have more cast iron lining inside than anybody else's. I don't see "recognizing problem areas" as a bad thing - it's a precursor to improvement. To see the trends, look at the most recent product introductions. You'll see less exposed metal inside. This is especially true of the other cast iron stovemakers, most notably Morso.

As time passes, standards are tightened, and stovemakers respond with new/upgraded products, the higher-tech insulating materials will occupy a higher percentage of the firebox interior. If we're lucky, the excellent materials that are currently prohibitively expensive will be more widely used and come down in price. And we'll all benefit from it, just as we did from the original standards. I'm quite optimistic about it all, actually.

 

[DanCorcoran]

cycloxer,

"Burn a full load of cord wood in a modern stove and then measure the real world efficiency and grams of particulates over the entire burn cycle and publish those #‘s. "

Measuring efficiency and grams of particulates is relatively easy. If you're burning cordwood, though, how can any testing agency or test protocol ensure consistency from one batch, one stove, one test site, one year, to the next? Surely that's the reason they use dimensional lumber: there's some consistency. And to measure efficiency and particulates, how do you do that except in a lab? Does every make and model of stove have to be shipped to my house for testing?

Seems to me, the tests don't need to be perfect, just consistent and repeatable.