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.