Esbit burner testing

[rmeurant]

Roger [1] ROGER™ © 2018, Moderator @rcaffin .

From the end of a packet of 4 g  of recently purchased in Japan, the text clearly states, and with fidelity to case:

“Esbit® ist ein eingetragenes Markenzeichen”.

Case in point: Could perhaps a special case be made for using title case rather than uppercase in case the OP is encased in a case of nerves? Or is that a cold case; or alternatively an open and shut CaSe?

1. From Roger, used circa 1940 in UK and US military communication to represent “R” when spelling out a word. “R” is the first letter in received, used to acknowledge understanding a message [2].

2. https://en.wiktionary.org/wiki/roger

[rmeurant]

Eric,
I need a drawing to follow your description (as I imagine you need for mine), but it does strike me that a great deal of heat is lost to the ambient environment (air and ground) in all ESBIT burners I have used to date. By capturing a significant portion of that heat, surely the efficiency would be improved? This suggests techniques to limit the conductive and radiant loss of heat of the pot/lid/burner/windscreen system.

[Roger Caffin]

Then the company has some internal inconsistencies.
Happens.

Cheers

[Eric Blumensaadt]

Robert and Dan,

Have you seen the Inferno insert in a Trigger Ti or Sidewinder cone?

It is suspended off the base safety sheet by a 1/2″ high circular “hardware screen” (1/8″ mesh) with a disc of the same mesh on top, The wood in the Inferno inverted cone sits on top of this elevated mesh disc and some ashes fall through but it’s mainly for air to come up into the Inferno ventilated cone.

I envision a double wall cylinder with say 1/4″ legs for air to enter the combustion area. The inner cylinder wall would be ventilated and the outer wall not ventilated. Ventilation pattern would be determined by trial-and-error experimentation. This cylinder would sit around the BEGT tab holder.

Don’t ask how I’d make the double wall cylinder B/C I haven’t begun to work on it. But I am collecting various sized cylinders. I must look a bit stupid holding my BEGT holder on top of various cans at the supermarket to find one of the correct diameter but it’s all in the name of “science” – or Weird Science.

Hopefully this “gassifier” cylinder would elevate burn temps by burning formerly unburned gasses given off in the initial combustion, the same as with wood gassifier stoves.  Nez pas?

[rmeurant]

Eric, no I’ve not seen the Inferno, but have long been interested in it. I have an old Ti truncated cone shape 4dog stove that is supposed to work wonders, but I could only get it really rocking a few times, and it required constant feeding with twigs; which you couldn’t really do without removing the pot. I could get it working reasonably with carbonettes (egg shaped compressed carbon – horrible to handle); but normally I wouldn’t hike with that fuel. We need a schematic of the Inferno…

[rmeurant]

Dan, Eric, I had a pleasant camp in the cold (first use of my new Japanese tent – Heritage Revo 1 – see http://heritage.co.jp/Gears/HI-REVO.html ), and found the Evernew windscreen worked well with the Vargo Sierra, as Dan preferred. Inadvertently, I set the windscreen on the narrow setting, but it still worked fine. The Vargo handle barely uses the cutout space, and I imagine a simple cylinder with air holes would work just as well. Then I switched to the 400. The main problem I have (with both) is if the base surface is not perfectly level, the base plate – a Ti disk (lid for a Snowpeak 450 cup I think?) – slides at the slightest provocation, and the Titrivet slides on it also, though it is remarkable stable, despite the dramatic sliding and wobbling. I guess the solution is a roughly textured base disk, like felt, or even sandpaper, but structural (rigid). Again, Dan’s superb 4g tray proved its worth.

[Eric Blumensaadt]

Robert,

SLIDING STOVES-> Gravity usually wins but a “hammered” surface might help with enough “sticktion”.

INFERNO INSERT-> Try to find a Trigger Ti or Sidewinder stove W/ that insert to see how it works. Very ingenious take on the gassifier concept.

You are correct on the problem with constantly feeding sticks to some gassifier stoves. However the TD stoves mentioned above have large enough openings that thumb diameter sticks can be inserted permitting you to leave the stove for 5 to 10 minutes depending upon whether you are using soft woods (5 min.) or hardwoods (10 min.) and depending on how fully stuff it. But for melting snow I love it B/C I don’t have to carry a lot of fuel, just Vaseline soaked cotton balls in a Ziplock.

NEW TENT-> I feel obliged to warn you of the Achilles heel of your tent design. Back in the mists of time (’70s) I had a Jansport tent of that same shape. Every time I opened my door in the rain the rain came right in on the floor. Same with snow only worse. You need to add a large “beak” over your door to protect the entrance. Either two struts into grommets in the tent body and pockets in the beak or a curved tubing in a sleeve at the beak’s front edge. Jus’ sayin’…

 

 

[DAN-Y]

Eric said:

gassifier wood burners such as the Canadian Bush Buddy and the American Inferno insert into titanium Caldera Cones by Trail Designs. These systems re-circulate unburned gasses and they are then burned the 2nd time around, so to speak. And these stoves are considerably hotter than non-gasifier stoves.

 

Eric’s statement is totally not true. I would like all newcomers to BPL to know that. All the information you’ll ever want to know regarding wood stove gasification and secondary burning is in the following thread:

https://backpackinglight.com/forums/topic/58682/

Definition of gasification:

<b>Gasification</b> is a process that converts organic- or fossil fuel-based carbonaceous materials into carbon monoxide, hydrogen and carbon dioxide.

[rmeurant]

Eric, yes I have several older tents with a third short (straight, not curved) cross pole, supposedly designed by Messner, the well-designed (Korean) Echoroba Fitzroy 1 (2 of), 2, and 3, just a little on the heavy side. I picked them up at various times, second-hand. Two doors, excellent environmental control, especially for the 1-man, which I used to tour with. But this new Japanese tent comes in at 960 gm, and is rather compact when packed, and I was quite taken by the ventilation; also some nice details. I’ve long wanted a Heritage tent – excellent quality, they have a long and respectable history (every year, I devour their latest catalogue in Rally Grass (Fukuoka), and inspect their current models). This is a new model, though I prefer the curved center door (and back vent) on the inner of their Espace Solo Ultimate see http://heritage.co.jp/Espace/SoloUltimate.html , but that is 1.34 kg. They also have the very interesting 1-2 person Crossover Dome at 700 gm at http://heritage.co.jp/Gears/COD.html ,which I walked in to purchase, but walked out with the Hi-Revo.

Dan, I read your thread on wood stove gasification and secondary burning – impressive treatment! And having now discovered the Firefly (starved for info here) via the Moonlight Gear webpage at http://moonlight-gear.com/ , specifically his UL hanging burner, I think I’ll try hanging your solid-white-fuel-that-shall-not-be-named tray on my Emberlite fire ant as an option, again for use with 4 g tabs, save the weight of the sixth solid fuel plate. Maybe I can rig it so it will also hang on the Vargo Hex. Peace!

[Eric Blumensaadt]

DAn,

So all these years I have been laboring under the misconception that “gassifier” wood stoves burned recirculated gasses unburned in the initial combustion. Hmmm…

What then, pray tell,  does the term “gassifier” refer to?

 

[Roger Caffin]

When you heat a bit of dry wood in a fire, it starts to decompose. All the hydrocarbons break down and come off as a gas, leaving charcoal behind. A stove which does this well could be described a a gasifier: it turns the wood into a gas.

During one of the Wars, a lot of cars had gasifiers at the back, to turn wood and coal into a fuel gas for the IC engine.

Cheers

[DAN-Y]

During one of the Wars, a lot of cars had gasifiers at the back, to turn wood and coal into a fuel gas for the IC engine.

 

[Eric Blumensaadt]

Correct, burning wood gives off gasses.

And gassifier wood stoves recirculate those gasses to be burned. Hence “gassifier” stove.

[Ken Thompson]

Well you know that now.

[Jon Fong / Flat Cat Gear]

Eric,

Look up pyrolysis and you can see what they mean by wood gas.  If burned correctly, you can heat up wood to give off “wood gas”.  Mixed with the right amount oxygen and you can create a nice blue flame.  Pyrolysis done correctly leave char and not ash.  I don’t believe that I have ever seen a small backpacking stove generate pyrolysis by the book.  They go through some cycles, but end up leaving ash.

My hypothesis for the dual walled stove that what they are probably doing is heating up the air before to being vented into the stove.  The hot air probably helps with a efficient burn (less smoke).  The gas wick in a wood gas stove is never really defined, I suspect that it is a way to heat up the wood gas prior to combustion.  My 2 cents

[DAN-Y]

And gassifier wood stoves recirculate those gasses to be burned. Hence “gassifier” stove.

Eric, that is incorrect. The gasses are not recirculated.

https://backpackinglight.com/forums/topic/58682/

[Mole J]

Theres always been a whole load of bad science (aka B.S?) around these Bushbuddy type stoves.

They  aren’t really gasifying the wood (like pyrolysis) any differently  to any fire. Or circulating anything.

It’s just secondary burn by introducing extra oxygen to the fuel via the top holes (in the form of warmed air once up and running) and allowing the unburnt gases/smoke to burn off.

A  version of what is achieved in modern household woodburners.

Secondary Burn.

 

[DAN-Y]

[Jon Fong / Flat Cat Gear]

Theres always been a whole load of bad science (aka B.S?) around these Bushbuddy type stoves.

While true, I suspect that there is some benefit to keeping the stove as hot as possible.  Pre-heating the air probably does not hurt.  If you look at pyrolysis, all of the magic happens at plus 400 F.  My 2 cents

[Mole J]

Oh for sure Jon Fong. I agree. There is often an advantage.

My BS  description was to do with the bogus explanations for what is happening rather than the performance.

[Matthew / BPL]

Let me preface this question by acknowledging that I haven’t read this whole thread and others like it. I have very little experience with wood stoves.

I get that Bushbuddies and Infernos are not true gassifier stoves. Does the injection of hot air up top have a benefit besides reducing smoke? Does it result in increased efficiency or higher temps or anything? Just curious.

[rmeurant]

And in relation to the thread topic – and a quite separate question – does the temperature of supplied air affect the efficiency of an Esbit burner? Is there a optimal temperature for the air that reaches the combustion area that should be aimed for in the design and use of the the burner; or is it simply a case that warmer supplied air is better; or that the temperature of supplied air is immaterial; or what?

A secondary question might be, is there any potential to apply the combustion characteristics of gassifier stoves to Esbit stoves? And separately, is there any potential to recirculate unburnt gas in an Esbit stove design to significantly improve the performance (or possibly the control of the burning characteristics, e.g. to achieve cooler/slower/longer or hotter/faster/shorter burning)?

[Jon Fong / Flat Cat Gear]

Matthew,

IMO, the holy grail of backpacking wood burning stoves would be a smokeless, soot free fire (complete combustion, an indigo/blue flame ).  I think that is damn near impossible for small stoves.  I don’t think of fuel efficiency as being an issue as the stored energy in wood is relatively high and the source is plentiful.  Much larger stoves have looked somewhat promising (smoke free and reduced soot) but they are not there yet.  Most of the success seems to be with wood pellets, a consistent fuel and not wood found in the field.

Robert,

ESBIT tends to be a sublimation process (solid phase to gas phase).  I tend not to see the liquid build up that people are talking about (wax?).  I personally have ESBIT stoves that pre-heats the gas but I would say that the overall impact is marginal at this time.

My 2 cents

[Mole J]

Matthew

With secondary burn, there is more combustion of the fuel going on, so one assumes more energy release?

Though, as Jon says,  in most cases where wood is burnt  there will be plenty of fuel available…

Nearly 10 years ago, I spent many evenings building and testing performance of several backpacking size woodburners from various cans.

My main findings was,  that above freezing,  a single wall can burner with top holes  is just as effective ( often faster) at boiling a pot of water as the same size double wall Bushbuddy style stove.   And it’s lighter.  ( Only one can!).  Mainly due to the fact the internal volume (i.e. fuel capacity/flame size) is bigger in the single wall burner.

 

 

[Eric Blumensaadt]

DAN, It ain’t a “great” burn-off unless there is a Tri-Ti or Sidewinder stove W/ Inferno insert in the competition.

OK, OK, OK! So maybe re-circulation of unburned gasses is not accurate. Perhaps the explaination given above that “secondary” air vented into the upper combustion chamber burns off those unburned gasses released in the initial combustion.

I very much doubt that hot air helps combustion. Colder air is denser with more air per cc or cu. inch. which better supports combustion. (Swedish woodburning household stoves have provision for outside air to enter the firebox. Double purpose-> 1. not sucking up warm room air for combustion and 2. introducing denser cold air to the fire. Win-win.

Roger! HELP! Am I off base here and need a dunce cap?

 

 

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