Pots With Heat Exchangers

[Edward John M]

Well my breakfast mug hold closer to 900mls and I need 2 of them to get motivated, which is why I have never understood the BPL fascination with tiny cup & stove combinations. I am perhaps at the extreme end of the spectrum where my breakfast is concerned I guess compared to some.

My small [ 1500ml useable 1700 actual] billy weighs 196 grams with lid and windshield so no great weight penalty and I guess not that much slower to boil than 500 mls heated 3 times

[DAN-Y]

Edward John, you started a thread that got me interested in pot skirts and so I applied the skirt to pots with heat exchangers. https://backpackinglight.com/forums/topic/diy-skirted-pot-query/

I did 10 boil tests today and averaged 5 grams of fuel usage per 500ml of water boiled. Average starting temperture of water was 65 degrees F/18.3C ambient air was the same but barometric pressure was low at 29 which equates to longer boil times. Stove used was Etekcity brand, has excellent simmer abilities.

[Roger Caffin]

Hi Dan
Ah, I see. It all its together now. Thanks.
Unfortunately, single serving pots are of no use to me as I am always cooking for two. More pot!

I like your use of tape for the lid handle. Kapton or Teflon?

Cheers

[DAN-Y]

It’s Teflon tape, good stuff for pot lid lifting.

What do you think of the 5 gram average for efficiency in boiling the 500ml?

[Roger Caffin]

Teflon – thought so. Good stuff.

5 g for boiling 500 mL? It’s a shade better than average.

We do a lot of local day walks in between longer walks, and morning tea is a big feature. Using an old aluminium Trangia kettle and allowing for two large 350 mL cups, I find I am using about 9 g of fuel each time. That is with windshield and running at no more than half power.
Thing is, the HX pot is a lot heavier than a simple HAA or Ti pot, so it would be a long time before the extra pot weight was compensated. Sigh.

Cheers

[DAN-Y]

Why are the Jet boil type pots so popular?

[Roger Caffin]

Pure marketing spin. ‘Think how much fuel you save! Less weight to carry.’ (3 g per day?)
Bah, humbug.

Cheers

[DAN-Y]

Marketing spin equates to outright lying when they say 30percent fuel savings?

[Roger Caffin]

Eh, well, yes and no.

Let’s compare boiling 1 L of water using an HX pot and a matched stove running at medium power on the one hand with boiling the same amount of water using a wide-head burner running flat out and a narrow 1 L beer can. I would not be at all surprised at a 30% fuel saving in that case.

But is this comparison one we as walkers would characterise as fair or realistic? I think not, but trying to go all ‘legal’ on the issue would be futile. Love that phrase in small print: ‘under selected conditions’.

It is a bit like vendors preaching the virtues of the MSR Reactor stove, while just accidentally failing to point out that the stove can emit something like 1,500 ppm of CO, which would be deadly inside a tent. Meanwhile a good upright stove emits something like 10 ppm of CO.

Cheers

[Mark Fowler]

My own very amateur playing with an HX pot did show savings in the 25-30% area.  The stove was run at low to medium and the setting not changed between pots (HX and plain) but the pots were of slightly different capacity and diameter. When the additional weight of the HX pot was factored in it only delivered weight savings if being used to extend the usage of the canister by a day or two rather than having to carry an extra canister to start with or a larger sized canister.  I prefer not to budget my fuel quite so tightly.

[DAN-Y]

It is a bit like vendors preaching the virtues of the MSR Reactor stove, while just accidentally failing to point out that the stove can emit something like 1,500 ppm of CO, which would be deadly inside a tent. Meanwhile a good upright stove emits something like 10 ppm of CO.

I seriously doubt the vendors know about the CO emissions.

The manufacturer says not to be used inside, outdoors only. They claim 30% savings. I would think they did the comparisons with same size pot having no HX fins and a control valve that is not regulated to prevent operator error at maintaining same gas flow rate (medium).

In my recent testing, I could have gotten better efficiency(4gr per boil of 500ml) if I reduced rate of fuel flow. Oh my! I would have to wait an additional 1 min for it to boil because I’m in the fast lane :)

4 gr divided into a 100gr canister is a whole lot of coffee heated for us solo walkers :)

 

 

[DAN-Y]

(@kramrelwof),My own very amateur playing with an HX pot did show savings in the 25-30% area.

I can see that happening.

Thanks for your research. Which stove do you use?

[Roger Caffin]

I seriously doubt the vendors know about the CO emissions.
Well, I KNOW that MSR knows all about it, because I told them. I sent them a full report from my BPL testing, with lots of data. They had not done any testing themselves. Yes, they read that report, and they immediately pulled the Reactor off the shelves for several months while they tried to improve the design. I think they managed to reduce the CO levels from 2,000 ppm to 1,500 ppm, or something like that. The CO problem is actually inherent in the design of the burner: not too bad flat out but terrible when turned down for cooking.

Actually, if my memory serves me right, Ryan and I had a bit of a row with the MSR managers and lawyers about this. Larry P would have turned in his grave: Mountain SAFETY Research indeed.

Now, do the vendors know about the danger? If they do not, then that is 100% the fault of MSR for not making it extremely clear to them. I would say that MSR have a duty of care there.

Sure, there is a paper warning with the stove about a CO hazard. Do you think the customers take much notice? You jest! Half of them would not even know what CO is. What do you think a walker caught out in bad weather is going to do – sit out in the storm because there a paper warning? Or dive into his shelter, do it up, and then light the stove?

He does get a bit excited at times, doesn’t he?

Cheers

[David Thomas]

Most of the side-by-side HX / non-Hx testing I’ve done shows a 30-35% fuel (or time) savings.  But that’s been on as-large to larger output burners (kitchen cooktop) than typical backpacking stoves.  And as a convenient and repeatable condition, I’ve used full output.  HX pots have more advantage at full throttle because there’s more wasted heat to potentially recover.  OTOH they were larger pots, so the non-HX pot was already pretty good.

Medium throttle on a backpacking stove and yeah, I’d expect 25-30% fuel savings.

Roger always chimes in with “you’ll (almost) never save the added HX weight with fuel savings”.

And I always respond, “Very often true, however you buy the $28 HX pot once, but $7-9 canisters repeatedly. And when it’s colder, there’s snow to melt, and you’re in a larger group; HX pots come into their own.”

I think we’re agreed that a clever, light windscreen are the more important grams to add before an HX pot.  Note that some HX pots like the Bulin S2500,  OliCamp XTS, many of the Fire-maple offerings and especially the Bulin S2400 have some wind-screen function incorporated into the pot.

Alas, none of the HX pots I’ve found to date are as light (thin-walled) as the lightest Toaks, Snow Peak or even Evernew Ti offerings.  If a truly lightweight pot like those were the basis of an HX pot plus an integral windscreen/shroud; then the weight penalty and the payback period (in people-days or liters-boiled) would be greatly reduced.  And, actually, if someone wants to pursue that, I’d suggest not the lightest Ti pot as a starting pot, but to start with the lightest aluminum pot.  Then aluminum fins (which are far better conductors of heat) could  be bonded / welded / integral to an aluminum pot and that avoids lots of issues.

[David Thomas]

And to correct my own post above, a bit of crashing around on eBay and the $25-$29 price point I recall from not long ago is throughly busted.  1.2-liter HX pot, $13, free shipping:

which is nicely wider / squatter than a lot of backpacking pots.

https://www.ebay.com/itm/1-2-L-Camping-kitchen-utensils-Outdoor-pot-portable-heat-exchanger-collect-G9D9/132408002594?_trkparms=aid%3D333200%26algo%3DCOMP.MBE%26ao%3D1%26asc%3D20171012094517%26meid%3D320d3bd50c2f4270aa588aaf00d93d62%26pid%3D100008%26rk%3D3%26rkt%3D12%26sd%3D123692562440%26itm%3D132408002594&_trksid=p2047675.c100008.m2219

Alas, they won’t ship from Hong Kong to Alaska.  Ironically, my son will be in Hong Kong next week, but I probably shouldn’t interrupt his investment-firm internship to chase down a cheap HX pot.

[Roger Caffin]

“you’ll (almost) never save the added HX weight with fuel savings”.
“Very often true, however you buy the $28 HX pot once, but $7-9 canisters repeatedly.”

I concede the point. Actually, the price of canisters is even higher in Oz.

Now, a challenge for all: can you find an HX pot like the one above (1.2 L – 1.5 L) withOUT the steel handle and bracket? I can’t help feeling that removing all that steel would see a very significant reduction in weight. To the point that I might consider buying one myself!

One could probably Dremel the rivets off and fill the holes with silicone sealant. The silicone would take the temperature. Or one could partly fill the holes with a large Al pop rivet, having punched the steel nail out first, then silicone. But ‘no hole’ would be much more couth.

Cheers

[DAN-Y]

pot skirts. Now, a challenge for all: can you find an HX pot like the one above (1.2 L – 1.5 L) withOUT the steel handle and bracket? I can’t help feeling that removing all that steel would see a very significant reduction in weight. To the point that I might consider buying one myself!

Roger, why not let the handles stay on and retire your 27gr MSR LITELIFTER. pot lifter.

One less piece of gear to loose, less “fiddle factor” one less piece to stuff inside your pot;)

I’m going to order some of the David’s newly found HX pots and create some awesome kits with HX

[DAN-Y]

Roger, your info on CO is well appreciated, thank you.

Yes, they read that report, and they immediately pulled the Reactor off the shelves for several months while they tried to improve the design. I think they managed to reduce the CO levels from 2,000 ppm to 1,500 ppm, or something like that. The CO problem is actually inherent in the design of the burner: not too bad flat out but terrible when turned down for cooking.

At least they listened and took action on the information supplied. Thank you for taking the interest and time to protect joe public. I wish Ryan and others would have done the same when I asked for assistance in reporting the unexceptable failure rate of the BRS3000T, 4 out of 7 melting. No warning went out to the millions of those who will purchase and use the failing stoves. No warning went out to those who manufacture the BRS, Only the few that read the words in these forums. All we can do is try! You did good Roger!

[Roger Caffin]

@Dan

I have tried to contact BRS management about the 3000T stove, but so far I have heard nothing back. Sigh.

Cheers

[David Thomas]

To assess how much might be saved by removing the steel handles and replacing the heavy-gauge lid with aluminum foil or a CF lid, I checked weights on a Bulin S24000 2.1 liter pot (orange trim on left) and an Optimus Terra Weekend HE 0.95-liter pot plus weird pot/frypan/lid thing for sauté-ing two goldfish (green trim on right).

Bulin S24000 2.1 liter:
Everything: 313 grams, 100%
Pot only: 227 grams, 73%
Lid: 44 grams, 14%
Handle: 42 grams, 13%

Optimus Terra Weekend HE 0.95-liter:
Everything: 286 grams, 100%
Pot only: 177 grams, 62%
lid w/ its handles: 78 grams, 27%
Pot handles, 31 grams, 11%

The Bulin I’ve used for 2-3 people and it seems about right for that.  It would be smallish for more people (but heats things fast, so maybe that’s fine).  It’s what I use the most around the homestead.  I work out of a garage loft and it’s a long, snowy, moose-infested hike, uphill in both directions, to the house, so I often boil a cup of water for noodles or tea in that pot (just the bottom inch) over a BRS-3000T on a cheap, Asian-store / tabletop burner butane canister.

The Optimus is just weird.  That lid/pan thing is stupid and the pot by itself is a very heavy gauge of aluminum (like standing on it is fine) and yet kind of small.  Solo, you’d need to use it for many weeks (without resupply) for the fuel savings to add up.

[David Thomas]

A treatise in defense of HX pots.

Besides providing frustrated engineers with a topic to discuss, HX pots:

Cost more (or not, see $13 pot above), but save money on fuel.

They save time when you’re really hungry, thirsty, want to get hiking again, or are feeding lots of people.

If your stove makes CO inside a tent, but is done 30% sooner, it made 30% less CO.

The more the heat goes into the pot, the less it heats up the handles of your pot.  To the point that you could consider a pot cozy a la JetBoil.

I’ve had instances like in warming huts in NZ, where my larger HX pot, brought for our party of 9, made hot water more quickly for 30 people who passed through the hut during our warm-up break.

I’ve used them at home when I was making many gallons of boiling water on the stovetop.

An ideal use would be at Everest Base Camp or a NZ hut or a Hawaii hut where the pot stays put for use by many people every day but the fuel has to be carried in (and, in NZ and Hawaii, every pound of propane is inside a pound of steel).

But for 1-2 people for 1 to 7 days out in summer?  The current HX pots add more pot weight than they save fuel weight.

[Roger Caffin]

@David
You have
Bulin S24000 2.1 liter:
Everything: 286 grams, 100%

I think the weight should be 310 g?

Cheers

[Roger Caffin]

why not let the handles stay on and retire your 27gr MSR LITELIFTER. pot lifter.

I think DT answered that one. The steel handles and clips are a lot heavier. And I can remove the pot lifter completely so it does not get hot while things are cooking.

Cheers

[David Thomas]

Roger, thanks. Fixed it.

[DAN-Y]

Roger I’m tempted to remove the handles from one of my pots to prove a point but I’m resisting :) I don’t think the weights would vary by much. Look at the photos and try to get a feel of the mass involved.

I think it was Franco that told us to leave the handles separated when heating and they will remain cool enough to lift without aids. He is correct. The HX skirt seen in the photo protects the handles from all heat, easy to pick up boiling pot full. The skirt is multi function, well worth the weight.

The BRS issue is a sad one, all resposibilities are on Ryan’s shoulders, he did the testing. Corporate greed is sad. Thanks for trying Roger, we’re good to go!

 

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