Heat Exchange Stove Shootout: Part 3
Heat Exchanger Stoves
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Addie Bedford
(addiebedford) - MLife

Locale: Montana
Heat Exchange Stove Shootout: Part 3<br>Heat Exchanger Stoves on 09/01/2009 21:14:44 MDT Print View

Companion forum thread to:

Heat Exchange Stove Shootout: Part 3
Heat Exchanger Stoves

Jason Livingston
(jasonlivy)
MSR Reactor... on 09/02/2009 02:18:23 MDT Print View

I, like a lot of people, want to cut through the hype and get to the actual facts. However, I do have a few questions, particularly about the Reactor. You mentioned that the Reactor couldn't simmer. Was the stove used on high in the test? In your opinion, could the flame adjuster be turned on half way to save fuel but still get the low boil times?

Another question is why so much emphasis on CO emissions? I know this is important, but this is a stove used primarily outdoors. Because it doesn't need a windscreen, there's no need to worry about it in enclosed areas (except if the weather necessitates being inside a tent, which mean you don't use a stove and wait out the storm). It seems this clouded the performance of the Reactor and was your opinion that it wasn't a good stove option. Just my observation...

Another question concerns using it in the winter. Because it has an internal pressure regulator, it doesn't need the same amount of pressure coming from the canister as the other stoves tested. I say this based on personal experience. I've used it in winter with excellent results melting large quantities of snow. Have you tried it in the winter? How do you know it won't work? I would love to see you to test the stoves in winter conditions (or in adverse weather conditions including wind and cold) and see which one does better. This is one huge aspect of all the stoves tested vs. traditional canister stoves that sets them apart. This will also help justify their design and place in the stove market. I think you will be surprised by the outcome...

I appreciate the effort made in getting this data together and enjoyed reading the report. Can't wait for Part 4:)!

Derek Goffin
(Derekoak)

Locale: North of England
Heat Exchanger Stoves" on 09/02/2009 02:59:36 MDT Print View

It is interesting what you find about heat exchanger stoves in winter conditions.When melting snow the efficiency will be more apparent than when raising water 80 degrees.

The summer upright heat exchanger is not a complete dead dog. Roger says "It would be fair to say that the amount of water you would have to boil to make any heat exchanger stove system more weight-efficient than an average Upright stove would be far (far) longer than any realistic resupply period for two or three people."
He did not test the original jetboil PCS. But assuming efficiency is similar to the GCS it is all down to excess weight. I have reduced the weight of my Jetboil PCS to 300 grams without affecting the burner/heat exchange. Plugging that into Roger's table my jetboil needs to boil 8.4 litres to start to compete with an average upright. The 2 of us will get there in 3 days.
Agreed the main reason I use it is ease of use as the stove can be handled while cooking and fits together as one, but we are often out there for more than 3 days. A heat exchanger system can be a lightweight summer option.
The PCS may be painfully slow but we have just used alcohol for 3 weeks. That is slow.

I can understand why Roger washed his hands of the complexity of the weight of the extra empty canisters but it is part of the equation. The average upright will only heat 9 litres of water with a 100 canister. The weight difference to a 220 canister is about 30 grams, that is the difference between my system and the average upright. So I would claim that as soon as the average upright needs more than 100 gram of gas my system gets its nose in front. That is also 3 days with our usage. Of course as the trip gets longer things continue to be complicated but you cannot write off a light heat exchanger so easily.

The is a typo in Roger's report. Under "Efficiency in real life" the column fuel/litre shows instead efficiency which is a sort of reciprocal.

Edited by Derekoak on 09/02/2009 04:37:36 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: MSR Reactor... on 09/02/2009 04:46:45 MDT Print View

Hi Jason

Yes, the stove was used on High for the tests.

I COOK dinner sometimes, and this requires a low flame to avoid either burning dinner or boiling the lot over. This canNOT be done on the Reactor. The basic Reactor design cannot simmer safely - I tried.

> could the flame adjuster be turned on half way to save fuel but still get the low boil times?
No. What you are asking for is high heating power at low fuel flow: life and stoves don't work that way. Sad.

> why so much emphasis on CO emissions? I know this is important, but this is a
> stove used primarily outdoors.
That depends very much on the weather, at least for me. If it is pouring rain I am NOT going to sit outside to cook. Anyone who does so at 33 F in a 40 mph wind and pouring rain is, to put it bluntly, a complete idiot. They are also risking their life. I cook in the vestibule of my tent, and have done so for the last ... I dunno, maybe 20 years. And I am prepared to put my professional reputation on line (Research scientist, PhD) and say this is safe - despite the lawyers at MSR etc. They are just trying to avoid any liability suits.

> except if the weather necessitates being inside a tent, which mean you don't use a stove and wait out the storm
I am sorry to be so blunt, but this is complete rubbish. You have obviously never been in a 24 hour storm in the mountains. You have obviously never been soaking wet in a hail storm and struggled to get your tent up and yourself inside, shivering frantically. Or, worse still, in a day-long snow storm at 2,000 m (6,600'). Under these conditions you do not fool around: you and your partners NEED shelter and hot liquids, and you need them NOW.

> Because it has an internal pressure regulator, it doesn't need the same amount of pressure coming
> from the canister as the other stoves tested.
Sorry, but this is false. The marketing spin about this was obviously written by someone with no knowledge of physics. If anything, slightly more canister pressure might be required to make the pressure regulator work properly, but the point is rather moot.

> Have you tried it in the winter? How do you know it won't work? I would love to see you to
> test the stoves in winter conditions
I don't need to wait for winter. I can stick the canister in the fridge. But this is unnecessary in practice. The way canisters behave at various temperatures is very well-understood physics. And I have spent plenty of winters in the snow cooking in my tent.

Yes, you could use the Reactor in winter at 0 C (32 F) with an iso-butane canister and get away with it sometimes. But you would need to keep the canister 'warm' (above -5 C), because at full throttle the canister is going to freeze down fairly fast - especially with a 3/4 empty canister. You could also try doing it with a butane/propane canister, but after a little while the stove will die due to differential evaporation rates. Read our articles on Winter Stoves for more information on this. In practice this can be a real hassle, and we do use remote canister stoves instead.

Time will tell about the Reactor. It looks glamorous, but it has real practical deficiencies imho.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Heat Exchanger Stoves" on 09/02/2009 05:01:16 MDT Print View

Hi Derek

> I have reduced the weight of my Jetboil PCS to 300 grams without affecting the burner/heat exchange.
Yeah, OK, but ...
* The PCS cannot heat 1 L of water to the boil safely. I was focusing on stoves which could cook for two in order to keep a level playing field.
* That is a nice weight reduction, but it is not a stock stove anymore.
* The PCS is a bit slow ...

> The average upright will only heat 9 litres of water with a 100 g canister.
True, but ...
* it can be hard to buy 100 g canisters in many places
* the 100 g canisters work out rather expensive
* the weight efficiency of the 100 g canisters in themselves is very poor
* for the purpose of comparison I was focusing on the fuel used without bringing the canisters into the equation.

So, yes, there can be some situations where the figures turn out to be different. I went with conditions which appealed to me; your situation may be different (ymmv). No worries.

> Under "Efficiency in real life" the column fuel/litre shows instead efficiency
> which is a sort of reciprocal.
Ah ... that does depend on how you define 'efficiency'. I chose to use fuel/litre because of the obvious benefit when calculating how much gas you need for a trip. Perhaps 'efficiency' is not the best word here - 'performance' might be better? Point taken.

Cheers

Derek Goffin
(Derekoak)

Locale: North of England
Heat Exchanger Stoves" on 09/02/2009 05:41:59 MDT Print View

Sorry to persist Roger, perhaps you should look at the table in your report! Performance or efficiency surely means that higher numbers are better. Fuel per litre would be lower numbers are better. In the column the more efficient heat exchanger stoves have higher numbers but it is headed fuel per litre that is surely wrong, a typo, not just a slightly wrong word.

Thank you for the accurate research, the scenarios we apply to it will all be more accurate because of it.

If you do not like 100 gram cartridges then everyone is carrying so much spare fuel that small differences in pot weight are almost irrelevant.

I accept that my system is no longer standard but it shows what a manufacturer could do if they wanted to.

You know the Jetboil insistence that you cannot use their one litre pot for more than 500 ml is there for the same reason that you must not cook in a tent. My reduced 800ml pot will cook 700ml, with care

Edited by Derekoak on 09/02/2009 07:43:22 MDT.

Jonathan Shefftz
(jshefftz1) - MLife

Locale: Western Mass.
Primus Eta Packlite on 09/02/2009 06:29:29 MDT Print View

Wow, now that is the kind of comprehensive review that keeps me a BPL subscriber!

"One could call this the reduced-weight version of the Primus Eta Power stove. Most of the comments written for the Eta Power will apply here as well."
-- Exactly why I bought it. I was very impressed with my Eta Power stove (even melting snow and then boiling water at -10F), but the weight, and more importantly the bulk, was going to be very noticeable on any sort of long ski mountaineering trip (other than just setting up a base camp).

"The PackLite does have some 'funnies' in its construction, as discussed in the Supplement 5 Review of it ..."
-- The link isn't working for me? Or at least it's just taking me to Part 5, with no apparent references to the Packlite?

"The one thing lacking with the PackLite is a good device for holding the canister upside down. An opportunity exists here ..."
-- Inspired by an internet photo of a cottage cheese container turned into an inverted canister stand, I took a 32 oz yogurt container and cut it up to create an inverted canister stand. It's quite stable, and with all the cut-outs and it's also of negligible weight. Only problem is that it works only with a medium-size canister. (I'll have to get some other dairy products containers for other canisters!)

Nicholas Luhr
(nhluhr) - F
Reactor in cold weather: it works on 09/02/2009 07:55:49 MDT Print View

Comprehensive review... but I would like to see the tables replaced with some charts or at least ordered from best to worst/etc to improve their usefulness.

I use my reactor specifically for melting snow BECAUSE it is the most powerful stove. When it's cold and you just climbed several thousand feet and you just want to crawl into your sleeping bag before an alpine summit start, that power is where you appreciate it.

Stick to Snow Peak canisters and you will be good down well below freezing since they contain no n-butane and have the highest concentration of propane of any compatible cartridge. I also DO sleep with my canister but that is not a hassle at all. I also sleep with wet glove liners, wet socks, etc in order to dry them for morning.

Edited by nhluhr on 09/02/2009 07:56:35 MDT.

Mark Keown
(aarnbodypacks) - F

Locale: NZ
Jetboil weitht on 09/02/2009 15:17:43 MDT Print View

The Jetboil kit is listed at 550g, one of the lightest in the list.
Under Summary you rate the Jetboil as too heavy? Please explain..

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Heat Exchanger Stoves" on 09/02/2009 21:47:17 MDT Print View

Hi Derek

> Performance or efficiency surely means that higher numbers are better. Fuel per litre
> would be lower numbers are better.

Well, take a look at the commonly quoted figures for fuel efficiency in a car. Litres per 100 km seems standard in the metric world. The lower the figure, the better. Yeah, different.

> If you do not like 100 gram cartridges
My bias, clearly. For day walks I don't really care about the canister weight but I do care about the running costs. And I can't buy 100 g canisters locally anyhow.
Most of my overnight walks are 4-6 days, and a 230 g canister is just right for cooking for my wife and me for that time.

> it shows what a manufacturer could do if they wanted to.
Oh, absolutely. What stops them?

> You know the Jetboil insistence that you cannot use their one litre pot for more than
> 500 ml is there for the same reason that you must not cook in a tent.
Ahhh... I interpret this as heavy sarcasm against the manufacturers and their lawyers - right? In which case I do agree.
All the same, I don't think I could safely cook dinner for the two of us in the Jetboil PCS pot. And given the grearter weight of the remote systems and the heat exchanger systems, I chose to assume cooking for two.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Primus Eta Packlite on 09/02/2009 21:51:59 MDT Print View

Hi Jonathon

I will check up on what has happened to the PackLite reference.
Oops - production error. The URL is for Part 5, not Supplement 5. I will get that fixed when Supplement 5 is published. Sorry about that.

> a good device for holding the canister upside down.
I have experimented with a myriad of devices for holding the canister upside down, including such plastic containers. For our latest 6 week trip through Switzerland I took 2 thin short Al wire stakes - and rarely used them anyhow. Most of the time I flipped the canister upside down and lent it against one of my joggers. That method worked just fine, at zero weight cost. Simple is Good.

Cheers

Edited by rcaffin on 09/02/2009 22:10:45 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Jetboil weitht on 09/02/2009 22:08:07 MDT Print View

Hi Mark

> The Jetboil kit is listed at 550g, one of the lightest in the list.
> Under Summary you rate the Jetboil as too heavy?

The Jetboil may be a heat exchanger stove, but it is also an upright. Many people find themselves limited in what canisters they can buy and are restricted to n-butane/propane. These canisters do not like the snow. Yes, I am being a little conservative here - for reader safety.

In consequence, the Jetboil GCS was not accepted as being suited to general snow use, although I acknowledge that a skilled used can get it to work a little below freezing by using an iso-butane canister. So it was being compared to other uprights, for safety. Exactly the same applies to the Reactor of course.

It was a lovely day of winter ski touring. The sky was clear, the wind was light, the snow was good, the conditions mild. We camped in a very pretty spot.
Next morning it was about 0 F. Not a time to be worrying about getting an upright to work!

Cheers

Tony Beasley
(tbeasley) - MLife

Locale: Pigeon House Mt from the Castle
Re: Heat Exchanger Stoves" on 09/03/2009 03:56:50 MDT Print View

Hi Roger,

Thanks for another great series of articles.

In part 1 the stirrer is a nice touch to smooth out the heating rate curve but it does not change the main results fuel per liter per 80C results

As you know I have been using and testing flux ring pots for a few years now, for winter my favorite is modified Coleman Extreme stove under a JetBoil GCS pot and I challenge any other stove pot system to melt snow as fast and efficient at 0F.

I would like to see some tests between your MSR pot and a GCS pot melting ice/snow at -20C but as we know to do this properly this would difficult to do and expensive for a home shed setup.

After years of playing and testing stoves I have come to the same conclusion as you, that the lightweight uprights with a lightweight STD pot cannot be beaten for three season use.

With the efficiency gains of the flux ring pots I suspect that the flux rings not only help with heat absorption from the larger surface area but give an advantage by slowing down the flow of the hot gasses over the bottom of the pot, therefore the hot gasses have more contact time with the bottom allowing more heat to transfer into the pot.

Tony

Patrick Egan
(pegan) - F
Gas cannister stove for use in cold weather on 09/03/2009 12:25:57 MDT Print View

Hi,
I am amazed at the detail of your tests, but what I really want to know is:-
I live in England and spend 2/3 weeks in March in arctic Scandinavia most years and wonder if a canister gas stove exists which will work in temperatures of -10ºC


Patrick Egan

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Gas cannister stove for use in cold weather on 09/03/2009 17:02:25 MDT Print View

Hi Patrick

> if a canister gas stove exists which will work in temperatures of -10ºC
No worries at all. You just need an inverted canister stove.

First of all, to understand what is going on, read the Winter stoves series:
Selecting a Canister Stove for Cold Weather Backpacking
Part I: Stove and Fuel Fundamentals
http://www.backpackinglight.com/cgi-bin/backpackinglight/selecting_stoves_for_cold_weather_part_1.html

Selecting a Canister Stove for Cold Weather Backpacking
Part II: Commercially Available Canister Stove Systems
http://www.backpackinglight.com/cgi-bin/backpackinglight/selecting_stoves_for_cold_weather_part_2.html

Then read Part 3 again.

Any inverted canister stove should work down to -20 C quite happily. Below that (or near that) you start to use some tricks, like dribbling a little cool water onto the concave bottom of the canister to keep it close to 0 C. But I would not hesitate.

Cheers

Edited by rcaffin on 09/05/2009 16:42:34 MDT.

John Borton
(ThinAirDesigns) - MLife
Reactor and snow camping on 09/04/2009 17:08:07 MDT Print View

I generally really like the completeness of reviews like this on BPL. There's one area on this review that really irks me however ...

Roger says in essence that the Reactor is generally unsuitable for snow melting due simply to it's canister design. He says this sort of negates all the power it provides. He hasn't tested the stove under those conditions, says that it's cold weather capabilities is marketing hype and says (in essence) that he doesn't need to test it because he understands physics.

Dude, I understand physics as well myself ... I also understand that it's a longstanding rule of science that it's the *job* of science to explain the repeateable physical phenomena. In short, the real world experience of myself (and others above and elsewhere) trump your knowledge of physics hands down.

The Reactor ROCKS when it comes to melting snow, even in surprisingly cold conditions (way colder than my other canister stoves function to any degree). This is my absolute GO TO stove for cold weather snow melting.

Before you call what MRS has done with this canister stove temperature wise marketing hype (woops ... too late) you should compare it's capabilities with any other canister stove and see for yourself.

Would I take it up Everest? Nope. Do I take it regularly in well below freezing snow camping situations as a way to melt LARGE quantities of snow in a short time. Freakin' yes. It's AWESOME for that.

Respectfully
JB

Willem Jongman
(willem) - F - M
Performance in windy conditions? on 09/05/2009 06:10:54 MDT Print View

I accept the conclusion that the higher weight of these stoves is only rarely made up by sufficiently lower fuel consumption. However, does this also apply in windy conditions? I am a happy user of Trangia and Trangia like alcohol stoves, and like the performance advantages of their integrated designs. Many of these heat exchanger cannister stoves are also of a more or less integrated design. That should be an added advantage in the real world that may count for much.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Performance in windy conditions? on 09/05/2009 17:04:40 MDT Print View

Hi Willem

> However, does this also apply in windy conditions?
Here we run into a problem with what might be termed 'reality vs lawyers'. It goes like this (with only slight exaggeration):

Companies like XXX (name deleted to avoid hassles) put nearly hysterical warnings on some of their stoves (the uprights) about how you must never ever on pain of immediate reprehensible and gory death use any sort of windshield around your stove or use the stove inside a tent or hut. These warnings are of course written by the company lawyers whose sole interest is to prevent you from ever suing the XXX company in the event you do something really stupid. Sadly, too many walkers believe the lawyers.
.
Cooking in the tent
.
On the other hand, we have many experienced walkers who have had to make hot food under absolutely atrocious weather conditions so they and their partners can just survive - and have done this in the shelter of their tent with a windshield around the stove. Not to mention cooking under milder conditions in the comfort of their tent. And they have been using their stove this way for the last 10 or 20 years without any incidents at all. (Yes, I HAVE checked the statistics.)

I have tried to discuss this issue with XXX management, but I was appalled by their complete refusal to even consider that the warnings they put on their stoves might actually be creating a hazard for their customers. Well, my own personal feeling is that XXX has been seriously irresponsible here. Some other companies have also followed suit with warnings, but not to the same degree.

The bottom line from all this, to get back to your question, is that trying to use a stove without shelter and a windshield is just plain silly. You should always use both. In which case the figures given stand.

Cheers
PS: XXX are a good company; my argument is with their lawyers!

Willem Jongman
(willem) - F - M
windy cooking on 09/06/2009 00:30:29 MDT Print View

Dear Roger,
I agree that there may be conditions where it is a lot wiser to cook inside the tent, and I have no reason to doubt your experiences. On the other hand, most conditions are not that extreme, and allow cooking outside. In the fourty years or more that I have done this, I have of course always used a windshield. Even so, having changed over to integrated alcohol stoves in recent years, I have been impressed by their performance in adverse conditions. It just seemed to me that even if their performance advantages in windstill conditions do not compensate enough for the added weight, the equation may work out differently in the wind.

Edited by willem on 09/06/2009 00:31:49 MDT.

Derek Goffin
(Derekoak)

Locale: North of England
shoot out msr windpro v primus eta packlite on 09/07/2009 06:57:06 MDT Print View

I can see I might be jumping the gun before part 4 of this interesting series but I want to reanalyze Rogers results for the windpro, the best non heat exchanger and the packlite, the best heat exchanger stove, for use in winter and melting snow.

Roger has the bottom line that you need 34 litres of water boiled before the packlite starts to beat the windpro. People will look at this and even for 2 people they will say that is 10 days or so, the contest is over, use the windpro.

As Roger tested them the weight difference is 132 grams but the packlite has a 90 gram windshield but could have been tested with the 71 gram windshield the windpro was tested with, that is 19 gram difference. The packlite has an igniter, to be fair head to head this should be removed I guess 15 grams. The windpro was tested with a 1.5 litre pot that comes with a pot lifter weight 29 grams, but it was not included. The packlite has an integral handle. Head to head the handle should be removed or the pot lifter included. 29 grams difference. make these amendments and the weight difference is down to 69 grams.

I use similar amounts of water to Roger. In winter we use 3 litres per camp maybe more but he has tested with an 80 degree C rise. In winter 100 degree would be closer. so I will multiply the fuel cost per litre by 25% to allow for the colder water. The sum is therefore how many litres does it take to use up the 69 grams of packlite extra weight. Each litre of water takes 3.85 (Roger's figure) x 1.25= 4.81 grams of extra fuel with the windpro so 69 /4.81 = 14 litres. By this time the windpro will have used more than one canister, 220 grams of gas. For us I see the break point as 4+ days. that is still a long time.
I do not own a packlite but it looks as if the base plate could be lightened. Also if you decided not to carry the packlite windshield and use a lighter one you could cut the windshield supports off the packlite feet. The only way to find those savings would be to do it.


If you must melt snow and boil, at camp only, you must almost double the gas used. If you must melt snow for the next day too you could triple the gas usage. In this final scenario anything more than one camp and the packlite would be lighter.

Most of the difference in weight is now the weight of the heat exchanger pot. The lightest winter stove is probably a primus eta packlite with an ordinary pot for short trips that dont melt snow, and take the heat exchanger pot for snow melting and longer trips

Edited by Derekoak on 09/07/2009 07:18:47 MDT.

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
Thank you Roger! on 09/07/2009 23:09:07 MDT Print View

Great series of tests. I own Vargo Jet-Ti and Brunton Flex upright stoves(like a Primus Crux only better, and made for Brunton by Primus). I use these with the pots listed below. I've found the Brunton Flex, with its wider flame ring, heats a bit faster and more evenly than the Jet-Ti.

I own two 1.5 liter pots. One is an older, plain, Teflon coated aluminum 1.5 L. pot by Traveling Light, makers of the Outback Oven (cloth fiberglass yurt-sheped pot cover).

The other pot is JetBoil's 1.5 L. pot W/ the "Flux Ring" heat exchanger and neoprene cozy. I find the JB pot does boil water faster than the regular pot but evidently from your tests not enough faster to save significantly on fuel on a week long summer trip to offset the weight difference between the two pots. However, it does melt snow enough faster in winter, saving fuel there. I'll continue to use the JB 1.5 L. pot for winter. For summer I've switched to the Travelling Light set's smaller 1 L. pot and homemade pie pan lid for weight savings. It still is a wide, low pot compared to many other 1 L. pots, which makes it more efficient.

With all my stoves, liquid fuel, canister or ESBIT, I use an MSR heavy foil windscreen. With my two upright canister stoves I must prop it up on small stones for better flame protection and it helps keep the canister cool as well.

Perhaps someone will find a way to make an aluminum pot & aluminum finned heat exchanger ring with the finned ring reinforced by an inner and outer wire laser welded to the fins, something like Primus does W/ their flat reinforcing ring. Steel heat exchanger fins, for reasons of weight, ain't the answer.

Eric
BTW, I also use the Outback Oven pot cover to melt snow faster in the JB pot. But in winter I'm using an MSR Dragonfly liquid fuel stove, a real "jet engine" of a stove yet with an amazing simmer capability.

Edited by Danepacker on 09/07/2009 23:30:08 MDT.

Lynn Tramper
(retropump) - F

Locale: The Antipodes of La Coruna
Re: Re: Performance in windy conditions? on 09/08/2009 14:56:55 MDT Print View

The "performance/efficiency" of the WindPro (or any other remote canister stove) can be increased even further by using it with a Caldera Cone instead of the stock windscreen. This also improves stability and wind worthiness dramatically...I wonder what it does to CO emissions?

Edited by retropump on 09/08/2009 19:52:44 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: shoot out msr windpro v primus eta packlite on 09/08/2009 19:45:14 MDT Print View

Hi Derek

Good analysis. I have no arguments at all. I especially liked the bit about melting snow taking almost double the amount of gas: I did not factor that into my calculations.

So yes, the PackLite has very good potential for winter camping for 2+ people, especially if slimmed down a bit.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Performance in windy conditions? on 09/08/2009 19:49:41 MDT Print View

Hi Lynn

I haven't tested the use of a Caldera Cone as a windshield on a remote canister stove. I would not expect it to do very much to the CO emission level provided there was reasonable air flow.

Warning to others: do NOT do this with an upright! ! ! Your life may be a bit shortened if you do.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Thank you Roger! on 09/08/2009 19:52:40 MDT Print View

Hi Eric

You selection of pots according to season has some merit. Spending a huge effort to save a few grams of gas is not always worth while - for instance carrying an extra cup of water will easily swamp the difference in weight.

> Steel heat exchanger fins, for reasons of weight, ain't the answer.
I don't think any of the pots I tested had steel fins - quite sure in fact.

Cheers

Michael Ray
(topshot) - MLife

Locale: Midwest
Poor Windpro performance? on 09/11/2009 12:26:35 MDT Print View

Just fired up my new Windpro for the first time and was surprised (in a bad way) by the results. I just want to verify if this is normal or not. I tried boiling 3 quarts of water and didn't reach a boil after 20 minutes.

Water was a little below room temp (out of the tap but I melted a tray of ice cubes in it to cool it further). Outside temp is about 78 F. Slightly breezy (10 mph). I used the windscreen with about 1/4" gap around the pot. I added maybe 10 small holes (paper punch) along the bottom so air could get in since the standard cutout they provide will be non-existent on smaller pots though about a 3/4" slit still remained. I did not use the heat deflector on the ground (concrete in this case) - I don't imagine I'd ever use it. Pot is just under 8" dia, fairly thin AL.

I had a few bubbles start at 7 min and then some steam at about 13-14, but never a boil. I'm at 600' ASL. The only 2 things I can think of are:
1) Losing too much heat from the pot itself to the breeze as I had purposely left the lid off also so I'd get a worst case baseline and could easily see when things occurred.
2) Not enough airflow. Either need more holes on the bottom and/or more gap around the pot.

I should also note, I wasn't sure how far to open the valve for max output. It was about 1/2 turn for about the first 7 min and then 3/4 turn after that. From what I could see through the slit and the pitch of the flame I could hear, it made no difference once I got past 3/4 turn so I left it there. Went through 48 g of fuel in the 20+ min.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Poor Windpro performance? on 09/11/2009 15:41:37 MDT Print View

Hi Michael

Well, 3 qt is a lot of water to heat in one go, and I do have some comments.

First of all, watch out for pot diameter. If the pot has a very large diameter you run a risk of reflecting too much heat back down onto the fuel canister, which can be extremely dangerous. We prefer to not lose readers to this sort of thing... I would say that 8" is getting a bit large, but should be OK. Using a windshield (as you did) does prevent this problem.

With an 8" pot with no lid and a moderate wind, it is quite possible that you had reached the point where evaporation was killing you. I find that using a lid and a windscreen can *literally halve* the amount of fuel used.

I don't think there would have been a lack of airflow. You would have seen a lot of yellow in the flames if this had been the case.

Another problem which I suspect may have happened was that the gas in the canister may have chilled down over the long time you were running the stove. When this happens the stove power starts to fall. Combine that with the possibility that you didn't have the stove turned right up at the start, and a very long boil time will happen.

48 g of fuel is a bit more than I would calculate for 3 qt, but very consistent with the idea that you were losing out to evaporation at the end. Use a lid!

Hope this helps.
Cheers

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: Re: Poor Windpro performance? on 09/11/2009 16:08:24 MDT Print View

I'd never boil without a lid normally, of course. Just curious to see what worst case would be. It was plenty hot for freezer bag meals and likely had been after maybe 10-12 min. I should have seen if I had a thermo I could have put in.

Anyway, I didn't know even with remotes you can get the canister too hot so it's nice to know that now though I'll always use a windscreen as well.

The canister was cold. The hose on the Windpro doesn't make it easy to flip the canister either unless you have a decent amount of water already sitting on the stove and return the canister right side up before removing the pot. I've thought about loosening the fitting and turning it about 90 degrees.

I did slowly flip the canister over for a while just to see how the stove would react. While I didn't observe the flame through the slit (it was challenge enough trying to get the canister into a position where it would stay inverted as I didn't have anything to lean it against), I did notice the sound pitch of the flame changed while it was inverted (~30 s) and returned to what it had been when the canister was returned upright. I hadn't expected that. I assume it must be a pressure difference in liquid vs gas feed?

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Poor Windpro performance? on 09/11/2009 16:16:06 MDT Print View

Hi Michael

> Just curious to see what worst case would be.
In the name of Science ... Interesting.

> you can get the canister too hot
Read our article on Exploding Canisters! Oh yes....
http://www.backpackinglight.com/cgi-bin/backpackinglight/exploding_gas_canisters_the_hazard_of_overheating.html

> The hose on the Windpro doesn't make it easy to flip the canister
Very true. Yes, many of us do rotate the connection a bit so the canister can be flipped.

> I did notice the sound pitch of the flame changed while it was inverted (~30 s) and
> returned to what it had been when the canister was returned upright
The power probably increased while it was inverted. Yes, if you want to run for long periods then inverting the canister will solve the freezing down problem. You can also get some boost by putting the canister in a bowl of *cool* (NOT HOT!) water.

It isn't so much a difference in pressure as a reduction in pressure drop along the fuel line. The fuel line does put some drag on gas flow. Same effect of course.

Cheers

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: Poor Windpro performance? on 09/11/2009 17:28:06 MDT Print View

> In the name of Science ... Interesting.

I'm an engineer so I like to play. :) Also why I enjoy your posts so much. ;)

> Read our article on Exploding Canisters!

I knew uprights had this issue but figured remotes were far enough away from significant heat to be an issue.

> Yes, many of us do rotate the connection a bit so the canister can be flipped.

Do you reseal the fitting with something? It appears they have some type of epoxy in the threads. For natural gas piping in the US, they use what is called pipe dope (a gray slimy substance that never hardens), but I didn't know if the threads used here have the same characteristics where that would work.

Tad Englund
(bestbuilder) - F - MLife

Locale: Pacific Northwest
Re: Re: Re: Re: Poor Windpro performance? on 09/11/2009 17:40:05 MDT Print View

Michael, I just wanted to emphasize what Roger said about rotating the canister-

You mentioned “The hose on the Windpro doesn't make it easy to flip the canister”

Yes, the hose makes it difficult to rotate the canister unless there is water in the pot. If you don’t rotate the canister fitting on the hose, you are just twisting the hose like a spring, causing tension and the canister or the stove will flip (probably and the most inconvenient time).

To fix this problem- you rotate the fitting for the canister independent of the hose. To do this, grasp the canister while firmly holding the hose and then turn either the canister or the hose. It will put up some resistance but it will turn. I leave the canister attached so I can tell, where exactly I need to rotate the fitting on the hose, to get the canister in the position I want. To get it back to the original position, just reverse the process.

I hope this helps and is not redundant

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: Rotating Windpro connection on 09/11/2009 17:51:54 MDT Print View

> To fix this problem- you rotate the fitting for the canister independent of the hose. To do this, grasp the canister while firmly holding the hose and then turn either the canister or the hose. It will put up some resistance but it will turn. I leave the canister attached so I can tell, where exactly I need to rotate the fitting on the hose, to get the canister in the position I want. To get it back to the original position, just reverse the process.

I hadn't tried to twist that hard but I'll give it a go. You don't keep twisting it back and forth do you? I figured having the connection midway between both positions (connection disc laying on edge) would suffice. My understanding is you always start upright and then flip the canister slowly to avoid any flaring so you're always using both positions.

Tad Englund
(bestbuilder) - F - MLife

Locale: Pacific Northwest
Re: Re: Rotating Windpro connection on 09/11/2009 18:10:13 MDT Print View

>You don't keep twisting it back and forth do you? I figured having the connection midway between both positions (connection disc laying on edge) would suffice. <
I just keep it in one position (inverted), because this is my winter stove and I use alcohol in the other seasons. You would only need to rotate it twice a year if it were your only stove. Once in the fall, then back in the spring.

>My understanding is you always start upright and then flip the canister slowly to avoid any flaring so you're always using both positions.<
I start with it inverted, you just need to be aware that the starting flame is different then in summer so "throttle down" accordingly. Practice this at home in the backyard before in your tent.

Edited by bestbuilder on 09/11/2009 18:13:09 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Poor Windpro performance? on 09/11/2009 21:50:39 MDT Print View

Hi Michael

> Do you reseal the fitting with something?
I did think about doing so, but decided to try retightening without at first. There seemed to be no problem, so I left it that. Yes, I DID check the fitting afterwards - submerse in water.

Some of the newer remotes (eg Primus) have a genuine rotating connection, so it is possible to rotate the canister freely. Very nice.

Cheers

Edited by rcaffin on 09/15/2009 22:09:46 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Rotating Windpro connection on 09/11/2009 21:54:52 MDT Print View

Hi Michael and Tad

> >My understanding is you always start upright and then flip the canister slowly
> to avoid any flaring so you're always using both positions.
This is a safe method if the hose connection can rotate, but it is not essential. I sometimes start with the canister already inverted and the flame set very low. I give it about 30 sec before I turn the valve up any more - with the pot on the stove of course. The 30 sec burn heats up the preheat tube and gets rid of any remaining liquid gas near the jet.

If you turn the stove off with the canister inverted it is usually possible to turn it back on without any drama.

Cheers

Brad Groves
(4quietwoods) - MLife

Locale: Michigan
Re: Performance in windy conditions? on 09/15/2009 18:58:15 MDT Print View

Hey, Lynn-

Have you used a WindPro in a Caldera Cone? Or a Ti-Tri? I'm thinking that the heat of the Windpro might melt the Cone, but not the Ti-Tri...? If you've successfully done it in the aluminum cone, that'd be great; my 2L one with a Windpro could be awesome for that 0*F weather...

M G
(drown) - F - MLife

Locale: Shenandoah
Rotating windpro on 09/16/2009 12:14:09 MDT Print View

I've got a windpro and I've tried to rotate the fitting as described above. I managed to turn it so the canister could lie inverted without coiling the cable. When I tested for leaks before using the stove by immersing the connection under water there was a substantial amount of bubbles leaking. So I suspect I've done soething wrong. I tighened it back up rotating the conection back to its original posittion. Unfotunately it appears to still be leaking gaz at the connection, albeit quite a bit less.

I suspect I'm doing something wrong. Can you be more precise about what you are rotating, if you are using an adjustable wrench to do so, and pictures would be useful. I would love to get this stove to work in an inverted position without having the cable coiled up.

Thanks.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Rotating windpro, and Primus Express Spider on 09/16/2009 17:05:47 MDT Print View

Hi Martin

The Windpro connection is actually a 'fixed' one. That is, there is no ability to freely rotate. Some stoves have some thread sealant on the connection at the valve/coupling which MOSTLY seals the thread even when the connection has not been done up tight. But this can let a few bubbles of gas leak out if the connection is not properly tight.

I suspect that many stoves have enough sealant there that the residual leakage does not prove to be a problem for the user. Some forms of the sealant stay a bit flexible and can handle some movement. Or maybe the users have not actually tested the connection under water. After all, a small bubble once every few seconds may not be found in the field as the gas would dissipate quickly and would not support a flame.

However, it may be that your stove does not have much sealant on the connection thread, and this is letting a very faint amount of gas leak out. I am going to have to put a public safety hat on here and caution against using the stove in this condition. It could clearly be dangerous.

What to do? You have three options:
* Do the connection up tight and leave it at that. Chancy.
* Get some liquid 'thread locker' and apply it before you do up the connection to whatever position you want.
* Try using a small bit of Teflon tape wrapped around the thread as a sealer.

Do test the result and do be a bit fussy: it's YOUR neck.

However ...

The Windpro is quite old now. There are more modern equivalents - the very new Primus Express Spider has definite possibilities. The burner is out of the PackLite (I think), the legs are light and the coupling at the canister rotates by design. The weight is about 195 g. (Brass and steel - think about a light-weight version!)
Express1S.jpg
Price unknown at this stage.

Cheers

Edited by rcaffin on 09/16/2009 17:06:28 MDT.

Tomas Reinhardt
(tomky) - MLife

Locale: Tatry
Lighter than Spider on 09/17/2009 16:00:48 MDT Print View

Edelrid Opilio 170g
Acecamp 4708 153g price: 30 Euro
Both with rotable coupling and better regulator for inverting canister

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Lighter than Spider on 09/17/2009 21:02:15 MDT Print View

Hi Tomas

Interesting. URLs?
Bear in mind our readership is largely USA: we miss out on a lot of Euro stuff.

Cheers

Franco Darioli
(Franco) - M

Locale: Melbourne
Heat Exchange Stove Shootout: Part 3 on 09/17/2009 22:37:36 MDT Print View

Here
http://www.acecamp.de/en/Kitchen/
scroll down to art 4708, listed at 160g
Franco

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Heat Exchange Stove Shootout: Part 3 on 09/17/2009 23:51:18 MDT Print View

Hi Franco

Hum, yes. Thanks.
I think I can identify the Chinese factory that came out of ... :-)

Cheers

Tomas Reinhardt
(tomky) - MLife

Locale: Tatry
Heat Exchange Stove Shootout: Part 3 on 09/18/2009 02:05:55 MDT Print View

Acecamp 4708 153g (weighted), my 113g mod: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=23089

Edelrid Opilio 170g
Catalog Sports10-GB(8.28 MB) page 81:
http://www.edelrid.de/index.php?option=com_facileforms&Itemid=629
see also Stormy Evo with Heat Exchanger, Hexon multifuel 220g
Video(German):
http://www.odoo.tv/OutDoor-2009-Kueche-Special.548.0.html

M G
(drown) - F - MLife

Locale: Shenandoah
Re: Re: Rotating windpro, and Primus Express Spider on 09/18/2009 17:46:07 MDT Print View

Hi Roger,

Thanks for the comments and the suggestion of the Spider, that and the other stoves posted by our European friends look lovely but unfortunately I am leaving in 4 days for a Sierra trip and need a cold weather stove now. This leaves me with a windpro and a bottle of loctite.

I completely unscrewed the connection and applied the loctite to the tube male part and rescrewed the adapter to the tube in the upside down position I needed. Once dry I tested it and it appears to be completely leak free...for now.

Thanks for the advice.

Hikin' Jim
(hikin_jim) - MLife

Locale: Orange County, CA, USA
Re: Re: Heat Exchanger Stoves" on 09/18/2009 21:22:42 MDT Print View

Tony Beasley wrote > ...for winter my favorite is modified Coleman Extreme stove under a JetBoil GCS pot and I challenge any other stove pot system to melt snow as fast and efficient at 0F.
Now that is a fascinating idea. I'll have to try that. I assume you use a windscreen also? Any tricks to help avoid melting the neoprene?

HJ

Edited by hikin_jim on 09/18/2009 21:41:37 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Heat Exchanger Stoves" on 09/18/2009 23:38:44 MDT Print View

Hi Jim

Tony will need to reply about using a windscreen, but I will bet you he did!

The neoprene - I worried that it would burn when I was testing several stoves with neoprene cozies. Somewhat to my surprise, I found that*provided the cozy was pushed right up to the rim* (so it didn't protrude at the bottom), there was no problem. The fins really suck the heat out of the flames. I found I could hold my hand in the exhaust stream beside the pot without any real problem. Try that with a bare pot! (DON'T!)

Cheers

Tony Beasley
(tbeasley) - MLife

Locale: Pigeon House Mt from the Castle
Re: Re: Re: Heat Exchanger Stoves" on 09/19/2009 00:46:25 MDT Print View

Hi Jim,

I always take a windscreen with me, for the Xtreme I use and old and very crumpled, cut down MSR Whisperlite windscreen but last time I used my Xtreme/JB GCS pot in 0F conditions it was in a hut without a windscreen (pic below). The only damage that the neoprene cozy has suffered is from rodents eating it in the same hut, the little plastic covering on the feet of my Xtreme stove was also attacked and I lost my candle and my mate had his cup stolen.

Tony

<center>
Xtreme stove and JB pot


</center>

Edited by tbeasley on 09/19/2009 00:47:50 MDT.

Hikin' Jim
(hikin_jim) - MLife

Locale: Orange County, CA, USA
Re: Re: Re: Re: Heat Exchanger Stoves" on 09/20/2009 18:18:12 MDT Print View

Roger, Tony,

Thanks, that's good information. The neoprene on JB's seemed at first to me to be a foolish thing (why put something that can melt on a pot for goodness sake?), but it's wisdom has become apparent over time.

HJ

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Re: Re: Heat Exchanger Stoves" on 09/20/2009 22:27:41 MDT Print View

Hi Jim

You didn't ask about wisdom.

My tests show the neoprene cosy has virtually no effect on the heating rate. But a lid has an enormous effect.

Cheers

Tony Beasley
(tbeasley) - MLife

Locale: Pigeon House Mt from the Castle
Re: Re: Re: Re: Re: Re: Heat Exchanger Stoves" on 09/21/2009 15:52:46 MDT Print View

Hi Roger

>My tests show the neoprene cosy has virtually no effect on the heating rate.

At warmer ambient temperatures this may be correct, at very cold temps I am not sure, we need to test the neoprene cosy at -20C.

>But a lid has an enormous effect.

I long time ago I did some tests boiling water with and without lids and at warmer ambient temps the lid made very little difference but at cooler temps it did.

If we can work out how to do affordable controlled cold temperature tests a series of tests on the above would be good.

Tony

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: Poor Windpro performance? on 09/21/2009 16:06:52 MDT Print View

I went through about the same amount of fuel (45 g, maybe a few less), but I boiled 3 L of water in about 9.5 min this time. This was with the canister inverted the entire time (I had just rotated the connection and this was my test for leaks). It was cooler today, but water had no ice added. This time of course I used a lid.

Perhaps closing the valve a bit would have saved some fuel as it still seems to have no effect on the flame or sound after about 3/4 turn. I suspect the valve orifice is the limiting factor at that point. I did notice the delay with the canister inverted, which didn't occur when it was right side up. Anyway, I think 3 L in 9.5 minutes is likely normal performance. Not sure about how much fuel that should take though.

One other variable this time was I was using a partial 8 oz canister rather than a new 4 oz one from before. Both MSR brand so that SHOULD not make any difference.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Lids on 09/21/2009 23:13:07 MDT Print View

Hi Tony

> warmer ambient temps the lid made very little difference but at cooler temps it did.

I was testing out a canister stove some years ago - not sure which one. I had it on a very low simmer, and just for the fun of it I tried running the rig with no lid. The water got to ~90 C and sat there. It would/could not get any higher. (Yes, the stove could do a very nice simmer.)

So after about 2 minutes just sitting there I stuck the lid back on. It shot up to boiling quite quickly.

I repeated the experiment with and without the lid after turning the stove off at 100 C. The difference in rate of cooling was very significant.

Cheers
-20 C - hum ... :-)

Hikin' Jim
(hikin_jim) - MLife

Locale: Orange County, CA, USA
Re: Re: Re: Re: Re: Re: Heat Exchanger Stoves" on 09/22/2009 01:14:25 MDT Print View

Roger Caffin wrote >

Hi Jim

You didn't ask about wisdom.

My tests show the neoprene cosy has virtually no effect on the heating rate. But a lid has an enormous effect.

Cheers
lol. Well, I suppose I didn't ask about wisdom did I.

Interesting. Doesn't at least the neoprene prevent heat loss while say, simmering? Or is the neoprene just a very fancy pot protector?

Speaking of lids, that's a big gripe I have with the GCS pot lid. It pops off and doesn't stay fully sealed when it gets hot. I just set it on top rather than fully sealing it, which is probably going to trap most of the heat I'd lose through evaporation (which I believe is the major component of heat loss), but for such a fancy and none-to-cheap pot you'd think they could have a better lid.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Re: Re: Re: Re: Heat Exchanger Stoves" on 09/22/2009 02:39:58 MDT Print View

Hi Jim

Well, all my tests suggest that the neoprene cozy is just another marketing gimmick, at least when you are using a stove of reasonable power. It ?might? be of some use when using a micro open alky and taking 15 min to boil a litre ... maybe.

Yeah, I know, 'all' the stove companies include a neoprene cozy these days, and surely they wouldn't try to sell you something you don't really need? Ahem. (But the cozy can take a huge logo screen-printed on it...)

Actually, with the titanium pots like the MSR Titan series, the heat conductivity is so low going up the side wall that there is not a lot of heat loss from there anyhow. I can grab the top edge of my 1.3 L Titan pot quite happily, so convection-based heat loss from the side walls is not going to be real great. Thick-walled aluminium pots might lose a whisker more, but what BPL member uses thick walled pots? The thin walled HAA pots should not lose too much heat from the side walls, I think, but I need to actually measure the heat loss before saying any more. (Tony may have done this already?)

Cheers

Hikin' Jim
(hikin_jim) - MLife

Locale: Orange County, CA, USA
To Neoprene or not to Neoprene. on 09/22/2009 11:50:18 MDT Print View

So it makes little difference in terms of fuel used and time taken whether one cooks with a neoprene cozy or not? Lol, the things they'll do for marketing. Well, at least on the JB PCS I suppose it helps to keep from burning one's hands when holding the pot/mug. Speaking of which, it seems like if the sides of the pot feel hot to the touch, they must be losing heat, yes? But it's just insignificant, is that it?

How about with multi-step meal preps where I might need to set the heated pot aside for a time while I work on antother step? Would a sitting pot benefit any from the cozy?

Maybe I'm really stretching here, loooking for some shred of value for the neoprene. :) Maybe I should just peel it off and save the weight.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: To Neoprene or not to Neoprene. on 09/22/2009 16:43:10 MDT Print View

Hi Jim

> if the sides of the pot feel hot to the touch, they must be losing heat, yes? But
> it's just insignificant, is that it?
I assume that you have a windshield around your pot. In that case the air coming up the sides between the pot and the windshield is probably hotter than the pot.

> Would a sitting pot benefit any from the cozy?
I do this myself, and yes, some insulation may help. Two buts:
* I find that the contents of my Ti pot are still hotter than I can comfortably eat after 10 minutes standing
* There are much lighter ways to insulate a pot than a neoprene cozy. I often use my bush hat - zero extra weight.

> Maybe I should just peel it off and save the weight.
Well, you could run some experiments with a thermometer. See what works for you. Don't just trust me!
(But do always question what the vendor claims!)

Cheers

Hikin' Jim
(hikin_jim) - MLife

Locale: Orange County, CA, USA
Re: Re: To Neoprene or not to Neoprene. on 09/22/2009 18:09:42 MDT Print View

Roger Caffin Wrote: >

I assume that you have a windshield around your pot. In that case the air coming up the sides between the pot and the windshield is probably hotter than the pot.
Which brings up another thought. If one is using a windscreen and the air moving up the sides of the pot is hotter than the pot itself, then the neoprene might actually be decreasing the amount of heat getting to the pot. lol.

At this point we're probably talking about hairs too fine to split. I guess the general ideas is that the neoprene isn't particularly essential.

Huzefa Siamwala
(huzefa) - M
To Neoprene or not to Neoprene. on 09/24/2009 05:57:13 MDT Print View

I think cozy would be of significant benefit only when using jetboil outside the vestibule in wind without windscreen.

Tony Beasley
(tbeasley) - MLife

Locale: Pigeon House Mt from the Castle
Re: Re: Re: To Neoprene or not to Neoprene. on 09/29/2009 00:57:57 MDT Print View

Part 1: It is often assumed that using a windshield it directs the heat from the flame up the side of the pot and therefore the sides will absorb heat into the water, this may be so with some stove systems but this may not necessarily be so with all stoves systems at all settings.

I have just run some tests measuring the gas temperatures up the sides of a pot with and without a wind screen and at different valve settings.

These tests are far from comprehensive and only one test per setting was conducted, a comprehensive set of tests would take more time than I have available to me at the moment.

Stove used a Kovea Supalite Titanium. Pot used a Snow peak Ti 1liter, Windshield very old modified MSR Whisperlite.

The first tests where done with a suspended windscreen that covered the pot and burner, The canister was not covered, the windshield was placed around the pot with about 1-1.5cm gap and the hot gas temperature probe was placed at the top to measure the hot gasses coming out the top gap (see picture 1).

Probe position WS
Picture 1

The tests where done in my garage under windless conditions at an ambient temperature of around 10C.

Results Windshield

Graph 1
Chart 1

Three tests where done using different control valve settings, slow, medium and fast, the medium setting as around what I use in the field.

Slow setting: 6.2g/80C, 10m 45s/80C.
Medium setting: 6.3g/80C, 5m 20s/80C
Fast setting: 7.2g/80C, 2m 59s/80C

Results: with the slow test the gas temperature did not raise much above around 40C, there is some evidence in the gas result line that the gas temperature is actually rising as the water temperature rises therefore it maybe taking heat away from the water in the pot.

The same could be said for the medium test but to a much lesser extent.

With the fast test some heat would be absorbed into the water from the sides but more gas was used.

Note that in all tests the gas temperature measured went up and down randomly, I am not sure exactly what is going on but I think that cooler air is being entrained with the hot gasses.


With chart 2 the probe was placed in three places and temperatures recorded, the first was with no windscreen (No WS top HR and No WS top gas) and was placed at the bottom of the pot 15 mm from the bottom 3 mm from the side (see picture 2), the second (No Ws bott HR and No WS bott Gas) also with no windscreen the probe was placed at the top (picture 3) 3 mm from the sides, the third placing was with a windscreen and the probe was placed at the top as per tests in graph 1.

pic 2
Picture 2

pic 3
Picture 3

graph 2
Chart 2: HR= heating Rate, Gas = gas temperatures.

WS top setting: 6.3g/80C, 5m 20s/80C
No WS top setting: 6.2g/80C, 5m 10s/80C
No WS bottom setting: 6.5g/80C, 4m 45s/80

With all three tests the settings where set at about what I would set the stove in the field (this is not exact science but with canister gas stoves it is very difficult to exactly to repeat tests.)

Results: It can be noted that with the top placed probes the measured gas temperature where lower than the bottom placed probe , my thoughts on this is that as the hot gas travel’s up the sides it mixes with the cooler surrounding air cooling the gas down, surprisingly this also happens when the windshield is used some of this heat loss my be from contact with the windshield but my guess is that as the hot gasses travel up th sides it entrains cooler air.

When I find time I will do some similar tests with my flux ring pot to look at the gas temperatures up the sides and to see if I can see if using the neoprene cozy makes any difference.

Conclusion: As pointed out in my earlier discussions these tests are not comprehensive but they show that in a windless environment using a windshield makes very little if any difference to the efficiency of a canister stove system, in a windless environment the main influence on efficiency is the valve setting

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Re: To Neoprene or not to Neoprene. on 09/29/2009 04:14:32 MDT Print View

Very interesting! Thank you Tony.
Makes sense - although I don't often have a windless environment!

Cheers

Derek Goffin
(Derekoak)

Locale: North of England
air temperature up the sides of the pot on 09/29/2009 05:09:31 MDT Print View

My take on those results is I do not have to carry such a tall windshield. one inch above the bottom of the pot may be enough, even in windy conditions. Extrapolating to flux ring pots, the air temperatures up the sides of the pot, after the heat exchanger can only be lower than for none flux ring pots. A Windshield's job is apparently to buffer the inlet air and the flame rather than the sides of the pot

Tony Beasley
(tbeasley) - MLife

Locale: Pigeon House Mt from the Castle
Re: air temperature up the sides of the pot on 09/30/2009 04:23:00 MDT Print View

Hi Derek,

>My take on those results is I do not have to carry such a tall windshield. one inch above the bottom of the pot may be enough, even in windy conditions.

My test on the STD windshield design show that in strong wind they may not be that efficient, I suspect that the wind travelling over the top of the windscreen causes a sucking effect, the hot gasses are then sucked up faster than normal causing loss of efficiency. But at the moment this is only a theory, I have to do some more tests to prove this.

Tony

Derek Goffin
(Derekoak)

Locale: North of England
windshield eta packlite in particular on 09/30/2009 06:26:23 MDT Print View

Hi Tony,
I am interested because We persuaded myself to buy a eta packlite and I intend to lighten it. One of the first candidates is the windshield. It would help a lot to understand windshields. The existing windshield is only 60mm tall yet 91 grams heavy and is mounted about 25 mm off the floor. A standard windshield that fitted in the pot when packed, would be limited to 80mm. The top of the flux ring when on the stove is about 70mm off the floor.

On another issue: help from anyone who has a packlite. Does the brass mixture tube from the jet to the burner unscrew at the elbow? Is the brass round base below the elbow solid? Can it just be cut off without exposing the internal cavity. The purpose of the round base appears to be to support the burner, but the burner is supported by a split pin and has very little weight on it.

Larry Risch
(dayhiker) - F
DON'T understand your charts on 10/20/2009 22:41:26 MDT Print View

Isn't the ETA Power fuel consumption of 7.9 / liter MORE than 6+ for the average remote or upright??!!

Larry Risch
(dayhiker) - F
I see now I think on 10/20/2009 23:41:32 MDT Print View

Looks like you put the minutes to boil in for the fuel per liter in that one chart, I can't see that chart while posting but the 6+ numbers should be 11.6 and 13.3 from the earlier chart. I get a bit different # of liters for the ETA power, the only one I checked, 24 liters and 92 liters, about the same.

Larry Risch
(dayhiker) - F
Another thought on 10/21/2009 00:29:52 MDT Print View

The weight difference of the stoves/pot is constant for the trip, while the fuel difference only reaches its maximum near the end of the trip, assuming you take the same amount of fuel for either system. (This favors Ti pots)


Another way to look at this is how many canisters you are going to take. Using your figures the ETA Power ,229 g fuel , / 7.92 is 28 liters, while the average upright and remote would get between 17 to 19 liters. So if you need to take an extra canister (12 oz) it becomes closer weight wise , but you also save some cost on fuel and waste of canisters? Partial canisters? Margin for error?

EDIT: In this case as the stove with the Ti pot burns more fuel the difference of the extra fuel weight should go down, except for the extra canister weight itself remains the same.

Winter time more fuel used to melt snow for drinking water. Snow is hard to melt?

Edited by dayhiker on 10/21/2009 07:31:28 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: DON'T understand your charts on 10/21/2009 00:31:06 MDT Print View

Hi Larry

I am not sure what you are asking. Please help me.

The Eta Power has a fuel consumption of 7.9 g per litre water, while the average for the Uprights (ie no heat exchanger pot) was listed as 11.6 g of fuel. I am not sure where you got the 6+ figure from?

Cheers

Derek Goffin
(Derekoak)

Locale: North of England
heat exchange stove shootout error in tables on 10/21/2009 01:31:35 MDT Print View

Larry has noticed what I pointed out earlier:

Sorry to persist Roger, perhaps you should look at the table in your report! Performance or efficiency surely means that higher numbers are better. Fuel per litre would be lower numbers are better. In the column the more efficient heat exchanger stoves have higher numbers but it is headed fuel per litre that is surely wrong, a typo, not just a slightly wrong word.

Under "efficiency in real life" Larry points out that his example the eta power uses 7.9 grams per liter whereas the average upright uses 6.5 grams per litre. As we know that heat exchanger stoves use less fuel to boil a litre something is wrong.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: heat exchange stove shootout error in tables on 10/21/2009 03:19:23 MDT Print View

Hi Larry and Derek

OK, now I get it. I think something happened along the way such that the last two lines in the published table under the heading 'Efficiency in Real Life' has the wrong figures. The values for the Uprights and Remotes are actually the time to boil from a previous table I think! Oops!
I will have this corrected ASAP - my thanks to you for seeing this.
(Edit: Addie tells me this has now been corrected.)

Now to the issue of the word 'efficiency' Derek suggests that 'Performance or efficiency surely means that higher numbers are better. Fuel per litre would be lower numbers are better.'

Well, not always. That is one definition of fuel efficiency, bolstered by the American practice of talking about 'miles per gallon' when discussing cars. But the rest of the world (which is all metric) measures a car's fuel efficiency in terms of 'litres per 100 km'. That's the same as grams per litre boiled.

You see, there is NO formal definition of the term, so it can mean anything you want it to - as the Duchess said to Alice. I take efficiency to mean using as little fuel as possible.

I suspect this argument may not have a satisfactory resolution, as we are proceeding from different origins. But can you suggest a better term which could be added to the article?

Cheers
Roger

Edited by rcaffin on 10/21/2009 15:40:12 MDT.

Derek Goffin
(Derekoak)

Locale: North of England
Heat Exchange Stove Shootout: Part 3 on 10/21/2009 03:51:47 MDT Print View

Hi Roger,
If you amend those 2 incorrect figures I have no argument with your meaning. I was just trying to explain why I knew they were wrong.

Larry Risch
(dayhiker) - F
Wrong numbers or Wrong words on 10/21/2009 07:49:52 MDT Print View

Derek:

"The is a typo in Roger's report. Under "Efficiency in real life" the column fuel/litre shows instead efficiency which is a sort of reciprocal."

I think Derek was thinking if the numbers are right the label is wrong?

Efficiency =C.L / g (oz) was about the same as the boil times for the average upright and average remote, 6+

I assumed the words were right but did not understand the numbers.

Edited by dayhiker on 10/21/2009 07:55:31 MDT.

Derek Goffin
(Derekoak)

Locale: North of England
Heat Exchange Stove Shootout on 10/21/2009 07:58:19 MDT Print View

Larry,
You are right

Tomas Reinhardt
(tomky) - MLife

Locale: Tatry
Part 4 on 10/21/2009 10:06:22 MDT Print View

Where is Part 4 ?

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Part 4 on 10/21/2009 15:43:35 MDT Print View

> Where is Part 4 ?

Still coming. My flow got interrupted when we headed off to Switzerland for 6 weeks in July. :-) :-) :-)

I have some higher-priority stuff to complete, then I will fire up the pots (so to speak). Anyone else noticed how the week flies past so fast?

Cheers

Joe Clement
(skinewmexico) - MLife

Locale: Southwest
Part 4 on 10/21/2009 15:46:20 MDT Print View

What everyone really wants to see is something blown up. Safely, of course.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Part 4 on 10/21/2009 17:50:36 MDT Print View

Hi Joe

> What everyone really wants to see is something blown up. Safely, of course.

Sigh - you should read the articles at BPL, especially the one on
Exploding canisters
! Your wishes would be answered. However ...
.
Burst2ExplodingCanisters
.
This burst at 100 C with one hell of a bang.

Cheers

Edited by rcaffin on 10/21/2009 17:51:00 MDT.

Hikin' Jim
(hikin_jim) - MLife

Locale: Orange County, CA, USA
Re: Part 4 on 10/22/2009 16:56:45 MDT Print View

I viewed the below linked video with the sound off, so I will not vouch for the narration, but the video is pretty interesting:
How not to use a stove.

P.S. The video is unnecessarily long. The action is at 7:47, so move the progress indicator to about 6 minutes when the stove goes out and he tries to re-light it.

Edited by hikin_jim on 10/22/2009 17:15:16 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Part 4 on 10/22/2009 21:17:22 MDT Print View

Hilarious. The guy is utterly ignorant and incompetent!

Cheers

Stephen CAUDWELL
(SuisseKayak23) - F

Locale: French Alps
Heat Exchange Stove Shhotout: Part 4 on 11/07/2009 06:05:27 MST Print View

Hey Roger,

What happened to Part 4 of this series - efficiency, pot diameter etc.

Michael Matiasek
(matiasek) - F - M
part 4 on 03/15/2011 15:15:38 MDT Print View

I was also wondering if part 4 and 5 are up yet? It has been nearly a year and half since the last post.

thanks

Mike

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Heat Exchange Stove Shootout: Part 4 on 04/19/2012 21:03:58 MDT Print View

Hi All

Yeah, been a while. I am still working on this with the help of Tony Beasley, but life has seriously intervened for both of us. I will try to get both of us back to it.

The short summary of our findings so far is that pot diameter does matter.
The larger the pot, up to a point, the better the efficiency of heat transfer. So beer cans are really inefficient.

Cheers