Innovation in Pellet Stoves

[DZL_Damon]

Somewhere in my readings, I came across a thread where someone running an industrial sized pellet boiler commented that they "grind" the pellets essentially into dust and blow them into the boiler.

I could have misunderstood what he was describing though.

That's how we do it! Very picky critter though! However we are burning it before the wood falls to the furnace floor, it's all burned in suspension.

The reason why I like my Kedel so much is it impliments MANY of the features my industrial boiler does for efficiency and convenience. "Soot blowing" (air vs steam), modulating control with a PID controller I can manipulate, O2 control with a PID controller I can manipulate, remote control (our boiler has been controlled from Sweden many times to save flight time from technicians), firing rate limits, stack temp read out with trending options on all parameters. An engineers dream!

However, the regular homeowner can set it and forget it too!


To get back to pellet stoves and EFFICIENCY more than an application feature there is much to be desired on that front from most the stoves I've witnessed personally. Exhaust temperatures are too high, o2 values vary with brands, heat exchangers ash up too quick, burn pots clog up too often. Without these options will you still burn wood? yes! However that is only marginably more sophisticated than my beloved wood stove.

I have seen first hand when I change brands of pellets my O2 controller will take over and drastically change my air and fuel rate settings! My friend with his Englander is stuck with only 1 or 2 brands that work "good" and a few more that work "ok". I'd like to bring our stack gas analyzer to his house to see the differences between all the pellets available in our area because they do make a LARGE difference! This can relate to combustion efficiency

As far as heat exchange goes, you could easily set up the stove to have more heat exchange surface area and even have a final stage pre heating cold OAK air. Temperature control in the exhaust could modulate a bypass around the final parts of the air heat exchanger to avoid condensation in the exhaust piping at low firing rates or start up periods. We've had air heaters with built in bypasses to avoid condensation for 100 years on industrial boilers. However it was even more important on those units burning Heavy Fuel Oil (aka Bunker C, HFO, RME 380+, #6 Fuel oil.... or basically sludge) since the high sulfur content of the fuel mixed with condensed water makes sulfuric acid!

 

[RKBAGUY]

I think that sawdust stove is the anti-tech solution.

 

[tjnamtiw]

That's how we do it! Very picky critter though! However we are burning it before the wood falls to the furnace floor, it's all burned in suspension.

The reason why I like my Kedel so much is it impliments MANY of the features my industrial boiler does for efficiency and convenience. "Soot blowing" (air vs steam), modulating control with a PID controller I can manipulate, O2 control with a PID controller I can manipulate, remote control (our boiler has been controlled from Sweden many times to save flight time from technicians), firing rate limits, stack temp read out with trending options on all parameters. An engineers dream!

However, the regular homeowner can set it and forget it too!


To get back to pellet stoves and EFFICIENCY more than an application feature there is much to be desired on that front from most the stoves I've witnessed personally. Exhaust temperatures are too high, o2 values vary with brands, heat exchangers ash up too quick, burn pots clog up too often. Without these options will you still burn wood? yes! However that is only marginably more sophisticated than my beloved wood stove.

I have seen first hand when I change brands of pellets my O2 controller will take over and drastically change my air and fuel rate settings! My friend with his Englander is stuck with only 1 or 2 brands that work "good" and a few more that work "ok". I'd like to bring our stack gas analyzer to his house to see the differences between all the pellets available in our area because they do make a LARGE difference! This can relate to combustion efficiency

As far as heat exchange goes, you could easily set up the stove to have more heat exchange surface area and even have a final stage pre heating cold OAK air. Temperature control in the exhaust could modulate a bypass around the final parts of the air heat exchanger to avoid condensation in the exhaust piping at low firing rates or start up periods. We've had air heaters with built in bypasses to avoid condensation for 100 years on industrial boilers. However it was even more important on those units burning Heavy Fuel Oil (aka Bunker C, HFO, RME 380+, #6 Fuel oil.... or basically sludge) since the high sulfur content of the fuel mixed with condensed water makes sulfuric acid!

Good info! You made me think back about 'blowing tubes' in Navy ships. Maybe we could blow tubes in our pellet stoves instead of the leaf blower solution. A healthy blast of compressed air up the stack would suck all the ash along with it and you don't have to be outside where the neighbors can cuss at you. My brother's destroyer was tied up at a wharf in Pearl right across from the Admiral's outside dinner party and someone blew tubes with the wind going right that direction!

 

[RKBAGUY]

You made me think back about 'blowing tubes' in Navy ships.

Not gonna say it. I'm just not.

 

[stoveguy2esw]

ive been "musing" to myself about a "gassifier" pellet stove think "non-cat" reburn would have to get past some serious airflow hurdles but i suspect a working non-cat pellet stove is achievable

 

[moey]

When pellet stoves compete with other pellet stoves there will be a lot more innovation. They currently compete with oil and propane which are so much more there really is not much competition. You could have one of the crappiest pellet stoves out there and at the end of the year you say wow I saved a lot of money not I wish they could have squeaked out another 20% efficiency.

 

[Snowy Rivers]

The one thing that comes to mind is, WHY do folks not look more towards alternative biomass fuels that in so many cases are very cheap.

Myself, I could really care less about squeaking a few more % of efficiency out of the stove when my fuel of choice is costing me 1.5 cents a pound

Currently, here in our locale, pellets are costing about 12.5 cents a pound.

I will say this, most companies that have a good working stove design are not readily going to change it simply for the sake of change.

There are several reasons for this too, 1- the cost of retooling their plant, or a vendors plant to produce the parts, 2- engineering costs, and likely the biggest issue is getting the stove re-certified.

Any time there are major changes in the design, other than simple cosmetics, the entire stove has to be re-certified.

That tag in the stove that reads Warnock Hersey, ahhhhh = $$$$$$$$$$$$$$$$$$$$$$$$$$

If it ain't broke, don't fix it.

Squeezing a couple % more heat efficiency out is not going to pay the heavy tariff on the re-cert.

The manufs had to thrash through all the RED TAPE to get EPA approval, and they want all the goody they can get out of it.

Snowy

 

[tjnamtiw]

When pellet stoves compete with other pellet stoves there will be a lot more innovation. They currently compete with oil and propane which are so much more there really is not much competition. You could have one of the crappiest pellet stoves out there and at the end of the year you say wow I saved a lot of money not I wish they could have squeaked out another 20% efficiency.

Very, very true, moey. When the other sources of energy are gone or legislated into extinction, or pellet prices 'necessarily skyrocket', only then will people care about that extra efficiency. It DID become a talking point this winter though when people couldn't find more than two bags a day at $8 a bag. That time will come again and the company that finds a more efficient stove first will reap the rewards.

 

[DZL_Damon]

Not gonna say it. I'm just not.

Our old joke when someone said they were gonna blow tubes was: "Who is Tubes?"

 

[tjnamtiw]

The one thing that comes to mind is, WHY do folks not look more towards alternative biomass fuels that in so many cases are very cheap.

Myself, I could really care less about squeaking a few more % of efficiency out of the stove when my fuel of choice is costing me 1.5 cents a pound

Currently, here in our locale, pellets are costing about 12.5 cents a pound.

I will say this, most companies that have a good working stove design are not readily going to change it simply for the sake of change.

There are several reasons for this too, 1- the cost of retooling their plant, or a vendors plant to produce the parts, 2- engineering costs, and likely the biggest issue is getting the stove re-certified.

Any time there are major changes in the design, other than simple cosmetics, the entire stove has to be re-certified.

That tag in the stove that reads Warnock Hersey, ahhhhh = $$$$$$$$$$$$$$$$$$$$$$$$$$

If it ain't broke, don't fix it.

Squeezing a couple % more heat efficiency out is not going to pay the heavy tariff on the re-cert.

The manufs had to thrash through all the RED TAPE to get EPA approval, and they want all the goody they can get out of it.

Snowy

Having visited UL labs on several occasions to get our products rated, I can agree that it is a big hurdle in time, frustration, and money. To justify the expense, one would have to make the complete leap to something revolutionary, which is not out of the realm of possibility. People talked about the restriction for going above 80% AFLU because of condensation but they failed to mention that, if you do that, you don't need SS flue pipe anymore! You can vent your stove, like high efficiency gas appliances, with PVC pipe going straight out the back of the stove through the wall.

 

[stoveguy2esw]

The one thing that comes to mind is, WHY do folks not look more towards alternative biomass fuels that in so many cases are very cheap.

Myself, I could really care less about squeaking a few more % of efficiency out of the stove when my fuel of choice is costing me 1.5 cents a pound

Currently, here in our locale, pellets are costing about 12.5 cents a pound.

I will say this, most companies that have a good working stove design are not readily going to change it simply for the sake of change.

There are several reasons for this too, 1- the cost of retooling their plant, or a vendors plant to produce the parts, 2- engineering costs, and likely the biggest issue is getting the stove re-certified.

Any time there are major changes in the design, other than simple cosmetics, the entire stove has to be re-certified.

That tag in the stove that reads Warnock Hersey, ahhhhh = $$$$$$$$$$$$$$$$$$$$$$$$$$

If it ain't broke, don't fix it.

Squeezing a couple % more heat efficiency out is not going to pay the heavy tariff on the re-cert.

The manufs had to thrash through all the RED TAPE to get EPA approval, and they want all the goody they can get out of it.

Snowy

this is a big reason for it , fielding a new model can be quite expensive , especially if its a "ground up" redesign. a company could have tens of thousands in "r and d" before the model is even sent to the testing facility where its going to be thousands more to have the stove tested and certified.

price of doing business

 

[tjnamtiw]

Our old joke when someone said they were gonna blow tubes was: "Who is Tubes?"

See someone beat you to it, RKBAGUY!

I wonder if that would work, though. I have a fork truck propane tank converted to a portable air tank with a big ball valve on top. Install a few tubes pointing up the piping and put a valve and quick disconnect on the end. Hook up the tank, pressurized to 130 psi, and open the valve! Don't answer the phone or the door......

 

[Snowy Rivers]

Back in days of the whifield stoves, they kept pretty much the same design for years, WITH ONLY MINOR COSMETIC MODS

 

[hoverwheel]

... Any time there are major changes in the design, other than simple cosmetics, the entire stove has to be re-certified.
..

Not just UL. I know of one software company that released service packs anyone else would call major Revs to avoid the cost of recertifying for Windows.

 

[Bioburner]

The smaller the better as far as consistent feed, I would think; however, from experience, I doubt that we could rely on any manufacturer to maintain a tight band. Don't forget Third Shift and Monday mornings!

Or when they outsource!

 

[ScotL]

See someone beat you to it, RKBAGUY!

I wonder if that would work, though. I have a fork truck propane tank converted to a portable air tank with a big ball valve on top. Install a few tubes pointing up the piping and put a valve and quick disconnect on the end. Hook up the tank, pressurized to 130 psi, and open the valve! Don't answer the phone or the door......

Our Kedel here has compressed air cleanout tubes in the back of the burn pot. There's 4 tubes, a solenoid, and a small air compressor that maintains 120 PSI. It does very well at cleaning the burn pot but that's all it cleans.

 

[RKBAGUY]

Y'know, with all the technical knowledge, skills and experience among this group, wouldn't it be great if we could start our own 'crowd-engineered' stove project that would incorporate the latest in design and materials? The parts could be fabricated on a group-buy scenario, and would ship in KD form for those intrepid DIY'ers who appreciate the hands-on approach. Kind of like what many 3D printer kits do. If any of you guys would be interested in such a thing, I could handle the web infrastructure to handle project management, document repository (for schematics) and e-commerce for group ordering.

 

[hoverwheel]

That actually is a pretty good idea. I can volunteer some programming wrt embedded controller and device drivers, although I suggest an analog version of the controller as an option.

Some of us live in overly protective states and it would be great if the stove could be UL listed. That adds overhead cost... Kickstart funding?

 

[RKBAGUY]

That actually is a pretty good idea. I can volunteer some programming wrt embedded controller and device drivers, although I suggest an analog version of the controller as an option.

Some of us live in overly protective states and it would be great if the stove could be UL listed. That adds overhead cost... Kickstart funding?

More or less what I was thinking... at a certain point when we have a working prototype we could go to kickstarter. Or just make the damned things ourselves. As to the UL approval, I don't know if that's necessary for things you make and/or assemble yourself. For example, the 3D printer kits are not UL listed, though some of the commercially-sourced Off-The-Shelf components (like the AC adapter) are, because those manufacturers obtained approval previously for that part on their own dime. However I'm not a lawyer so we'd need to speak with someone who is knowledgeable in that area.

Anyway, if we get enough fellas here who are willing to chip in on the project, I'll be happy to build the website infrastructure which would consist of:

• Bulletin board for engineering discussions
• Project management utility for assigning tasks/milestones
• Document repository for access to electrical and mechanical diagrams (CAD/PDF files)
• Donation component to help us pay for web hosting, and other hard development costs like materials
• Ecommerce to support sales/group purchases

The real key will be to find committed members here with knowledge and skills in the various areas adequate to the task. But how cool would it be to have a crowd-sourced or 'open source' stove project! ! ! !

 

[hoverwheel]

I suggest starting a new thread for it, requesting a sticky so it stays near the top, and post a wish list of features. See if some people bite.

(and post a link to it in here)

 

[longlivethejeep]

Wow, saw this at the right time! Love to see where this goes. I'd suspect the many dealers/engineers of existing stoves on this site would likely scoff at the idea though. It may not even be possible (legally) to sell a DIY stove. Sounds like a good way to meet that lawyer... who's suing you for DIYers who've burnt their house down building it wrong or improperly. Not to mention, homeowner's insurance may be difficult to acquire, or may refuse a claim based on such. Not that I think it's a bad idea (personally, I LOVE it, and wish I had something to contribute to it). For example, I've seen some people convert their stoves to include WVO. Once the alteration is performed, insurance will no longer cover it. just my opinion, however I am neither an engineer or lawyer.

 

[RKBAGUY]

I wonder what Ben Franklin (who designed a stove himself) would have to say about concerns over regulatory compliance and product liability. I mean, jeepers... seems you can't do a thing nowadays without the gummint having a microscope up your butt.

Does anyone know of an attorney who might be able to answer the question for us?

 

[hoverwheel]

... I mean, jeepers... seems you can't do a thing nowadays without the gummint having a microscope up your butt ...

I almost went to prison a couple years ago for fixing my gutters myself, instead of hiring a contractor.

 

[Lake Girl]

I almost went to prison a couple years ago for fixing my gutters myself, instead of hiring a contractor.

What??

 

[Dr.Faustus]

I dont need a stove thats going to come on here and tell everyone how I lazily put off cleaning it another day because tomorrow it's going to be 30 instead of 15, or constantly uploading selfies of itself to facebook.