Forum Index » Editor's Roundtable » Lightweight Integrated Canister Fuel Cooking Systems State of the Market Report 2011: Part 1 – Overview and Performance Evaluation


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Stuart R
(Scunnered) - F

Locale: Scotland
Re: Is It Really Jet Size? on 10/01/2011 14:12:49 MDT Print View

"If the jet sizes are are larger on some of the stoves, how come the warm-calm results are so similar?"

Jim - this is where I think the regulator comes into effect. In warm conditions, there is plenty pressure in the canister so the regulator does what it is designed to do - regulate the gas flow to some predefined maximum rate, so all stoves heat the water at much the same rate (only the Reactor is faster). The contol on the stove may be fully unscrewed, but the gas won't come out any faster due to the regulator. It is therefore the action of the regulator that allows a larger jet to be used with a given burner head size (giving the benefit when the gas pressure is low) without excessively large flames or lift-off when there is adequate pressure.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Re: Re: Regulator Valve vs. Needle Valve on 10/01/2011 15:15:42 MDT Print View

> A friend has a Sol Al. He and I will probably take it out tomorrow and see how it
> runs and what kind of warming the canister experiences.

Yes please! A report would be greatly appreciated.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Is It Really Jet Size? on 10/01/2011 15:26:12 MDT Print View

> The contol on the stove may be fully unscrewed, but the gas won't come out any faster
> due to the regulator. It is therefore the action of the regulator that allows a
> larger jet to be used with a given burner head size (giving the benefit when the gas
> pressure is low) without excessively large flames or lift-off when there is adequate
> pressure.

Agree, but everyone should note that you can achieve EXACTLY the same effect by simply adjusting the valve on the stove. A 'pressure regulator' and a 'needle valve' have EXACTLY the same effect on the gas pressure at the jet.

As with a propane system with its far higher tank pressure, the pressure regulator on these stoves is really just a safety device. Yes, it does allow the use of a larger jet size, but so what? A smaller jet gives the same gas flow when it has a larger driving pressure, and our propane/butane canisters have plenty of pressure (except when very cold, see below). The only difference is at those last few moments in the life of the canister, when all the liquid fuel has been used up and there is only gas left in the canister. Well, at that stage you are going to have to replace the canister in a minute anyhow.

There is a marketing myth promoted by some that a pressure regulator can somehow make a canister work *better* when really cold. That is a violation of the basic laws of physics, and just does NOT happen.

Cheers

Hikin' Jim
(hikin_jim)

Locale: Los Angeles, CA, USA
JetBoil Sol (Aluminum) Testing on 10/01/2011 20:43:34 MDT Print View

> A friend has a Sol Al. He and I will probably take
> it out tomorrow and see how it
> runs and what kind of warming the canister experiences.

Roger Caffin wrote:
Yes please! A report would be greatly appreciated.

Cheers

A friend of mine recently got a JetBoil Sol (Aluminum), so over I went for a bit of testing.

As I've mentioned, I've been a bit curious as to why the various versions of the JetBoil Sol outperformed other stoves in cold-calm conditions. I also brought out a Reactor, another of the stoves featured in Will's report.

Our test subjects (front row):


As one might expect, the Reactor came to a boil first:


But this isn't a contest; I'm trying to understand why the Jetboil Sol beat out so many other stoves in Will's testing in cold-calm conditions. Roger has posited that the "cut outs" in the burner allow heat to radiate to the canister, and that the warmer canister accounts for the Jetboil Sol's better cold weather performance.

If indeed thermal transfer is occurring, then I ought to be able to detect it here:


The lower portion of the JetBoil Sol Al's burner was warm but still touchable by hand after about 15 minutes of operation.


By contrast, the lower section of the MSR Reactor's burner was too hot to touch after just a few minutes of operation.


Also, the canister of the JetBoil Sol Al did not noticeably warm to the touch after 15 minutes of operation.


I could feel a little bit of heat on the back of my hand when I held it as shown above, but nothing so great that I wanted to move my hand away.

Admittedly, feeling by hand is hardly the paragon of scientific rigor, still, if a significant amount of heat transfer were occurring either through the burner's attachment to the canister or via radiation through the cut outs, it ought to be detectable by simple manual means. I detected no such heat.

I'm inclined to think Stuart's aperture size conjecture may be where the explanation of the improved cold weather performance lies, although my simple tests can't completely rule out thermal conduction or radiation..

HJ

Edited by hikin_jim on 10/01/2011 20:48:42 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: JetBoil Sol (Aluminum) Testing on 10/01/2011 20:55:40 MDT Print View

Are you attempting to measure performance purely on the basis of speed to boil?

What about fuel efficiency, like grams of fuel used to boil a given volume?

Some people want speed, and some want fuel efficiency. Then equate that to stove carry weight. Nobody here wants a heavy stove unless it gains a lot in speed or efficiency.

--B.G.--

Hikin' Jim
(hikin_jim)

Locale: Los Angeles, CA, USA
Re: Re: JetBoil Sol (Aluminum) Testing on 10/01/2011 21:47:28 MDT Print View

Bob:

Take a look at this graphic from Will's article:


Notice how most of the stoves had a much longer "boil time" (as defined in Will's article) when the boil was conducted under cold-calm conditions vs. warm-calm conditions. Note however that the two versions of the JetBoil Sol did not. Why did the Jetboil Sol do so much better than the other stoves in cold-calm conditions?

HJ

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: JetBoil Sol (Aluminum) Testing on 10/01/2011 22:12:44 MDT Print View

Don't ask me. Ask the author.

I own only one of those stoves.

--B.G.--

Stuart R
(Scunnered) - F

Locale: Scotland
Re: Re: Re: Is It Really Jet Size? on 10/02/2011 04:18:49 MDT Print View

"There is a marketing myth promoted by some that a pressure regulator can somehow make a canister work *better* when really cold"

Agreed, a regulator can't make any difference to the pressure in the *canister*, but it *can* make a difference to how the stove performs in the cold. As I posted on the previous page, a larger jet will allow a greater gas flow at a temperature a couple of degrees above the boiling point of the gas mixture, so the stove will have a good flame in this situation as opposed to a feeble flame on a conventional stove with a smaller jet. The regulator then kicks in in warmer temperatures to prevent the gas flow from getting too great for the burner head to handle. Of course, below the boiling point of the gas mixture nothing is going to get any stove to work.

Paul McLaughlin
(paul) - MLife
Re: Re: Re: Re: Is It Really Jet Size? on 10/02/2011 15:51:16 MDT Print View

Stuart - would it be a fair paraphrase of your point to say that the regulator equipped stoves (if also equipped with a larger jet) should have an advantage in a fairly narrow temperature range that lies near, but just above, the temperature at which the canister no longer has adequate pressure to deliver fuel to the burner? and that this advantage might be magnified when the canister is near empty?

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: JetBoil Sol (Aluminum) Testing on 10/02/2011 18:31:29 MDT Print View

Hi Jim

> By contrast, the lower section of the MSR Reactor's burner was too hot to touch after
> just a few minutes of operation.
> Also, the canister of the JetBoil Sol Al did not noticeably warm to the touch after
> 15 minutes of operation.
> I could feel a little bit of heat on the back of my hand when I held it as shown
> above, but nothing so great that I wanted to move my hand away.
> Admittedly, feeling by hand is hardly the paragon of scientific rigor, still, if a
> significant amount of heat transfer were occurring either through the burner's
> attachment to the canister or via radiation through the cut outs, it ought to be
> detectable by simple manual means. I detected no such heat.

Interesting, but not convincing. I was not suggesting that there would be a huge amount of heat coming down, just enough to warm the canister by a small amount - say 5 C. That you could feel some heat on the back of your hand is enough for me.

To go any further would require a temperature probe on the canisters. You might also need to do the test at sub-zero temperatures.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Re: Is It Really Jet Size? on 10/02/2011 18:38:11 MDT Print View

Hi Stuart

> a larger jet will allow a greater gas flow at a temperature a couple of degrees above
> the boiling point of the gas mixture, so the stove will have a good flame in this
> situation as opposed to a feeble flame on a conventional stove with a smaller jet.
Hum, yes, but ...
For the pressure regulator to work there must be a pressure drop across it. At the very least there will be a pressure drop due to the construction of the valve inside it. Will this pressure drop be greater than that across a needle vale which has been turned wide open? Normally I would think so, but I might be wrong.

As noted by OP, this effect only applies over a rather narrow temperature band, and I can't help thinking that the canister will often cool down right through that band when in use in the field. Which is why we use remote canister stoves ...

> Of course, below the boiling point of the gas mixture nothing is going to get any stove to work.
Totally agree, and it is marketing spin which suggests otherwise which attracts my ire. Separate issue though.

Cheers

Hikin' Jim
(hikin_jim)

Locale: Los Angeles, CA, USA
Re: Re: Re: Re: Is It Really Jet Size? on 10/02/2011 23:04:26 MDT Print View

Suart Robb wrote: Agreed, a regulator can't make any difference to the pressure in the *canister*, but it *can* make a difference to how the stove performs in the cold. As I posted on the previous page, a larger jet will allow a greater gas flow at a temperature a couple of degrees above the boiling point of the gas mixture, so the stove will have a good flame in this situation as opposed to a feeble flame on a conventional stove with a smaller jet. The regulator then kicks in in warmer temperatures to prevent the gas flow from getting too great for the burner head to handle. Of course, below the boiling point of the gas mixture nothing is going to get any stove to work.
Stuart:

Your explanation is the most consistent that I've seen yet with the results of Will's tests. The difference in results in cold-calm conditions for the Jetboil Sol stoves is quite dramatic, dramatic to the degree that I doubt that the amount of heat I detected in my simple tests would account for it.

Of course at some level, we're still speculating. I wonder if Will might have the means at his disposal to measure the aperture of the jets used in his tests.

HJ

Stuart R
(Scunnered) - F

Locale: Scotland
Re: Re: Re: Re: Re: Is It Really Jet Size? on 10/03/2011 06:27:38 MDT Print View

Alan - yes, almost. The stove with the larger jet should have an advantage over a narrow temperature range when the pressure in the canister is low. This is not 'magnified' when the canister is nearly empty, rather the temperature at which the effect should be apparent will depend on the canister contents. With a full Jetboil canister this may be around 0F, rising to around 15F as the canister is nearly empty.

Roger - I would think the pressure drop across a wide open regulator would be similar to a wide open 'needle' valve, and a good deal less than across the jet.
regulator diagram

Jim - If you or anyone else has access to a JB Sol and some copper wires in the range AWG 20 to 30, it could help answer this conjecture to know which size of wire will just fit inside the jet.

Tony Beasley
(tbeasley) - MLife

Locale: Pigeon House Mt from the Castle
Re: Re: Re: Re: Re: Re: Is It Really Jet Size? on 10/03/2011 13:11:22 MDT Print View

>If you or anyone else has access to a JB Sol and some copper wires in the range AWG 20 to 30, it could help answer this conjecture to know which size of wire will just fit inside the jet.

I have access to a Profile Projector http://www.mitutoyo.com/TerminalMerchandisingGroup.aspx?group=1427 and I have measured a few stove jets with it, (a lot of jets appear to be laser cut) While I have a PCS and quite a few other upright stoves I do not have a Sol and at the moment I am saving up for a tramping trip to NZ and I am not willing to divert my funds to get a Sol (which are expensive in Australia), I also have a stove testing lab, with a canister temperature measuring probe and a flame profiler.

So if if someone is willing to loan me a sol (or even better donate one) for testing purposes I am happy to do some jet size measuring and stove testing to see what I can come up with.

Tony

Tony Beasley
(tbeasley) - MLife

Locale: Pigeon House Mt from the Castle
Re: Is It Really Jet Size? on 10/03/2011 16:01:33 MDT Print View

My Jeboil PCS (primus valve) the jet size is 0.21 mm with such a small jet I suspect even the older JetBoil valves have some form of pressure regulator or gas flow control in them, I am unable to pull the valve apart to check.

Other stove jet sizes, Gnat 0.32 mm, Kovea Supalite Ti 0.30 mm, MSR Pocket Rocket 0.34 mm, One Road 153g remote canister stove 0.40 mm.

Some of these jets have different jet hole designs, the JB, Kovea and PR all have flat tops on the jet but the Gnat and one road stoves have tapered holes and the smallest part of the hole is below the surface.

Tony

Edited by tbeasley on 10/03/2011 16:02:18 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Is It Really Jet Size? on 10/03/2011 16:24:07 MDT Print View

"the Gnat and one road stoves have tapered holes and the smallest part of the hole is below the surface."

What does that accomplish?

--B.G.--

Jim Sweeney
(swimjay) - MLife

Locale: Northern California
Levon/Amazon 9/27 on 10/04/2011 16:19:56 MDT Print View

Levon, thanks for the Amazon tip. Purchased one, but notice that the price on Amazon, as of today, is back up to 145. -- possibly because of the buzz generated by this review!

Now the best price (for the next few minutes, anyway) seems to be at:
CombatTactical.com

Edited by swimjay on 10/04/2011 16:25:33 MDT.

Ben Pearre
(fugue137) - MLife
"Cold"? on 10/10/2011 16:27:44 MDT Print View

Where can I go backpacking and see the night-time low of -15C warm to 10C by breakfast? Isn't any discussion of melting snow rather speculative when the canister is used in such a warm environment? The canister should warm sufficiently to boil the isobutane in within 5 minutes, right? Another consequence: slower burn rates will look better for this test without reflecting real-world performance.

I was very much looking forward to a test of the regulator stoves. To what extent does a regulator improve performance of isobutane/propane canisters operating (upright) at, say, -15C, or even -5C, throughout the lifetime of the canister? I don't see why they'd improve cold-weather performance at all. [edit--oops, I posted this before I'd read through the whole thread. I see now that I'm right about regulators, but I'm still curious about -5C performance.]

Also, I'd love to see tests in stronger winds.

Edited by fugue137 on 10/12/2011 11:25:36 MDT.

James Klein
(jnklein21) - M

Locale: Southeast
Re: Jetboil SOL Ti on 02/01/2012 13:35:27 MST Print View

I crunched the numbers on Ryan's 30x.7L boils on a 100gram canister claim....

I think he is off by a factor of 2 -- maybe he meant he used a 200gr canister?

I come up with (based on fuel energy denisty and water heat capacity):

100gr of fuel is capable of raising the temp of 21L of water by about 57C or ~100F (ie if each .7L started with water @ ~50F then each could make it to ~150F). This assumes 100% of the heat makes it to the water, I bet this efficiency is closer to 75%.

Maybe Stuart or Roger can check my math.

Inaki Diaz de Etura
(inaki) - MLife

Locale: Iberia highlands
Re: Re: Jetboil SOL Ti on 02/02/2012 07:12:44 MST Print View

> I think he is off by a factor of 2

that was also my conclusion back up in the thread