Question For Our Resident Pellet Professors

[fireitup]

How is it physically possible for heat output (I know, BTUs) to vary so dramatically between different pellets? They're all made with basically the same process. I'm sure there are variables in type of wood used, binder materials, moisture content, etc., but I still don't see how the output differences can be that drastic. I posted a while ago that Trae Heats gave me almost NO heat output; as a newbie I was surprised that low an output was even possible. So yesterday I burn a few bags of North American pellets from Dopey Depot, and literally the same thing, almost no heat. Woke up with the 2nd floor feeling on the cool side. Dislike them so much I'm returning the remaining 9 bags to get my cash back. Bought my first ton of Chow today from HD in Bristol. $249, no tax. Been burning Chow almost exclusively so far. I liked the FSUs too. With my Breckwell on 3 of 5 settings, I can't sit within 5' of the front of the stove with Chows burning, too hot. Ran the N. Americans all night long on 3 and was not impressed. So what's the scientific explanation for why some pellets suck and other's don't...LOL.

 

[CladMaster]

Moisture is one factor, the other factor is the density, the less moisture and the more density is the key to pellets burning hot and it does not matter if it's softwood or hardwood.

I have had some of both softwood and hardwood that have produced next to no heat, yet other brands that produce so much heat that I've had to turn the stove down or off.

Here is some more info ..... download the pdf file.

 

[Husky]

How is it physically possible for heat output (I know, BTUs) to vary so dramatically between different pellets? They're all made with basically the same process. I'm sure there are variables in type of wood used, binder materials, moisture content, etc., but I still don't see how the output differences can be that drastic. I posted a while ago that Trae Heats gave me almost NO heat output; as a newbie I was surprised that low an output was even possible. So yesterday I burn a few bags of North American pellets from Dopey Depot, and literally the same thing, almost no heat. Woke up with the 2nd floor feeling on the cool side. Dislike them so much I'm returning the remaining 9 bags to get my cash back. Bought my first ton of Chow today from HD in Bristol. $249, no tax. Been burning Chow almost exclusively so far. I liked the FSUs too. With my Breckwell on 3 of 5 settings, I can't sit within 5' of the front of the stove with Chows burning, too hot. Ran the N. Americans all night long on 3 and was not impressed. So what's the scientific explanation for why some pellets suck and other's don't...LOL.

I'm new with pellets also and have noticed the same thing. My best pellets have been American Wood Fiber (Ultra Premium White Pine). I have tried DryCreek Premiium, Barefoot, Insta Heat and Green Supreme. My worst by fare are the Green Supreme. Seems like half the heat of American Wood Fiber.

 

[mustangwagz]

i have found that pellet size is also a factor...mainly cuz of the amount of pellets that get fed out to the hopper. If your pellets are longer, they'll take up more space in your auger. The more space they take, the less that fills the auger tube..and in return, ya get less falling into the burn pot. I noticed this when i was burning Dry creeks and Somersets. The dry creeks burn fine and put out lots of heat if you crank up the feed rate cuz they are longer/bigger. The somersets are smaller, and ya get more in the auger tube, so more pellets hit the burn pot quicker which leads to a bigger fire. i found that for ME, i just keep corn mixed up with the dry creeks or somersets to fill the void in the auger tube and keep a good solid amount of fuel hitting the pot every time the auger turns. It took me a little bit to figure it out till i watched it and thought about it. Hell, the auger would turn 2 times with the dry creeks before id get a few pellets out, whereas with the somersets every time it turned i got a decent amount outta the auger. So i bucket'ed the DC's out, mixed in corn and manually fed the non-corn mixture into the pot untill i got corn out there....then my temps were back in the usual area.

crazy, however..very understandable.

 

[alternativeheat]

I'm new with pellets also and have noticed the same thing. My best pellets have been American Wood Fiber (Ultra Premium White Pine). I have tried DryCreek Premiium, Barefoot, Insta Heat and Green Supreme. My worst by fare are the Green Supreme. Seems like half the heat of American Wood Fiber.

Those AWF White Pines are an excellent pellet FWIW. They burn hot and super low ash. I get great heat from the TSC pellets made by Maine Woods as well, those are blends, very hot. More ash though. These are good pellets both at prices not often found around here for a quality pellet, because of the big box outlet source. Most smaller yards get more money . Right now HD has Stove chows here, they can keep them.

 

[Skier76]

I've had good luck with Stove Chows and the AWFs. I'd give a slight edge to the AWFs if I had to rate them side by side.

In my stove, the Chows burn just as well as the Okie Golds...but for less money. YMMV.

 

[alternativeheat]

I've had good luck with Stove Chows and the AWFs. I'd give a slight edge to the AWFs if I had to rate them side by side.

In my stove, the Chows burn just as well as the Okie Golds...but for less money. YMMV.

Ya the Chows give good heat. I have better pellets to use right now so they can keep them ( more ash than I like but they do give good heat). Sometimes even though I have pellets if I see some really good ones I'll pick up some loose bags as well. If they brought in Blazers I would buy some. Stove Chows are not Blazers by any stretch of the imagination. Speaking of HD here.

 

[Husky]

Those AWF White Pines are an excellent pellet FWIW. They burn hot and super low ash. I get great heat from the TSC pellets made by Maine Woods as well, those are blends, very hot. More ash though. These are good pellets both at prices not often found around here for a quality pellet, because of the big box outlet source. Most smaller yards get more money . Right now HD has Stove chows here, they can keep them.

I picked up a ton of the AWF at a grand opening of a Runnings store in Oct. for $219 a ton. Wish I would of bought more. They now run $269 at the same store.

 

[Lake Girl]

From a previous thread:
Found this little tidbit on (broken link removed)
Softwood vs Hardwood pellets
Through the pelletizing process, wood is ground fine then the sawdust is compressed to make wood pellets. Although hardwood is naturally more dense, after compression, both the hardwood and the softwood pellets have equal density. But, because most softwood species have higher levels of resins, softwood pellets will produce more BTUs per pound generating more heat and producing less ash than hardwood heating pellets. (bold my emphasis)

They have both hardwood and softwood and have done the Twin Ports Testing for both:
(broken link removed)
(broken link removed)
Both these pellets are likely made on the same equipment with the difference being feedstock not compression.

However, add the variances in compression depending on manufacturer and their equipment, you can have very different burn properties.

And the discussion continues...

 

[Tonyray]

I was a Big Advocate of Stove Chows last winter..
They we're HD's best pellets I thought..Awsome heat but a crapload of Ash.....
Alas, I have since then burned lower ash pellets and am not a fan of the Chows anymore..
Especially since HD is gauging buyers with the 20 and 30.00 a ton Increase...
at 229.00 ton last year they we;re worth buying...
I discovered Douglas Fir Blazers this past week at of all place, HD... same price as the other brands they sell..That was deff a Score...
Talk about " where did the ash go" and 9200 BTU's.. Had 5 tons of Pellets in the basement and made room for at least 35 bags of blazers..
Even less ash than the Energex Golden Pellets I have...
have them jammed in the in the left corner pix here...
note: If Chows we're all that I could get and was in need of pellets, I would get some but there are many other less ash pellets going for same price now as HD keeps creeping up prices on lower end pellets... buy local dealers if you can.

 

[chken]

How is it physically possible for heat output (I know, BTUs) to vary so dramatically between different pellets? They're all made with basically the same process. I'm sure there are variables in type of wood used, binder materials, moisture content, etc., but I still don't see how the output differences can be that drastic. I posted a while ago that Trae Heats gave me almost NO heat output; as a newbie I was surprised that low an output was even possible. So yesterday I burn a few bags of North American pellets from Dopey Depot, and literally the same thing, almost no heat. Woke up with the 2nd floor feeling on the cool side. Dislike them so much I'm returning the remaining 9 bags to get my cash back. Bought my first ton of Chow today from HD in Bristol. $249, no tax. Been burning Chow almost exclusively so far. I liked the FSUs too. With my Breckwell on 3 of 5 settings, I can't sit within 5' of the front of the stove with Chows burning, too hot. Ran the N. Americans all night long on 3 and was not impressed. So what's the scientific explanation for why some pellets suck and other's don't...LOL.

Well, it's not. We know that pellets vary about 10% or so in BTU content. The only difference is the stove and your settings. While stoves are fundamentally the same, we all know that each of our stoves have certain likes and dislikes. Some have noted pellet length being a primary difference maker. My personal feeling is that if your stove is getting such poor results, poorer than what you would expect, then you need to adjust your settings. It really shouldn't be possible for your stove to produce no heat with any pellet, particularly if other stoves are getting heat from the same pellet.

 

[Wilbur Feral]

First, CladMaster and Lake Girl: Excellent posts and information you passed along. Very helpful. As you note, moisture content is a big factor because releasing moisture (H2O) requires energy that is not released as heat. But once the drying process at the mill removes moisture down to comparable levels, what else is going on?

Chken: Agree that difference is likely within + / - 10% range, but disagree that this is insignificant. If we assume average pellet is ~ 8000 BTU / lb, that's an 800 BTU difference, or range of 7200 - 8800 BTU. You can adjust your stove all you want, but you can't just produce nonexistent caloric content; you can only extract that caloric content (measured in BTUs) more or less efficiently.

I propose that it all boils down to CARBON, the oxidation of which is the primary source of energy in biomass or fossil fuels. But here's a little more info:

First, a table from the Engineering Toolbox (always a great site) showing heat values of various wood species when stored as cord wood: http://www.engineeringtoolbox.com/wood-combustion-heat-d_372.html. Helpful, but doesn't really answer the question.

Utah State University also has a similar, helpful table on heat content by species: http://forestry.usu.edu/htm/forest-products/wood-heating

However, if you REALLY want to delve into this, read the Wood Fuels Handbook from AEBIOM.org: (broken link removed to http://www.aebiom.org/IMG/pdf/WOOD_FUELS_HANDBOOK_BTC_EN.pdf)

The relevant information starts at about page 20 of this link, and goes on for many pages. I can't easily copy and paste from it, but the net-net is that energy (caloric value) is stored as Carbon, Hydrogen, and Oxygen (a carbohydrate) in various combinations that vary just a bit depending on wood species, with carbon being most important. Species with higher carbon content can store higher caloric values, and thus produce more heat. Carbon is also the reason fuels in other forms (such oil and gas) work so well: Those fuels have very high carbon content, and thus have much energy to release.