Pots With Heat Exchangers

[DAN-Y]

I came across this pot today on ebay. The pot is unique to have a double wall to channel the flames through the exchanger and up the side of the pot for a short distance and then out the exhaust holes. Just wanted to see if anyone has a pot like this and give some input on how well it performs.

 

Aluminum Camping Water Pot Outdoor Kettle Heat Exchanger Pot 1.5L

https://www.ebay.com/itm/Portable-Aluminum-Camping-Water-Pot-Outdoor-Kettle-Heat-Exchanger-Pot-1-5L/322553056168?hash=item4b19a90ba8:g:8EkAAOSwLsBZP131

 

 

[Jerry Adams]

$30 isn’t bad.  They don’t give a weight.

[Serge Giachetti]

Looks like a hybrid between a jetboil and a reactor. A little on the heavy side for the volume compared to the jb and reactor pots, but the design looks efficient. The quoted +%30 increase in efficiency seems in line with other heat exchanger pots. Jetboil is the gold standard for efficiency though.

[Ryan Jordan]

Cooking system efficiency in these integrated heat exchanger-type systems is a function of both the pot design and the pot-burner interface.

Depending on what stove you use, you’ll see differences in efficiency (also: let’s define efficiency as “fuel weight consumed per volume of water boiled”).

This article presents some data that shows two heat exchanger pot systems, with dramatic differences in efficiency that are dependent on the burner type and the burner-pot interface.

That said, the price of the pot you showed is pretty good, but consider the context of the whole system you are trying to build.

[DAN-Y]

I’m thinking to incorporate a titanium cone into the recessed area shown on the bottom of the pot. Use a Starlyte XL3 burner to provide the heat source which has worked very well with the Sterno Inferno pot.

The design of the pot looks like it would max out the heat exchanging.

[David Thomas]

Another thing that design might do is extract enough heat from the flame that you could put a neoprene cozy around the upper part of the pot.

[David Thomas]

It’s also available from other eBay vendors for US$25 with free shipping.

[DAN-Y]

I ordered one today. I needed a pot big enough for 2…..heh heh, justified

https://www.banggood.com/Naturehike-1_5L-Aluminum-Heat-Exchanger-Pot-Portable-Outdoor-Cookware-with-Bowl-and-Spoon-p-1184699.html?cur_warehouse=CN

[David Franzen]

One vendor claims abweight of “Approx. 370g”. That is 13.2oz.

[DAN-Y]

Jetboil 1.5 Liter FluxRing Cooking Pot

$49.34

Jet Boil says theirs is = Weight: 12 oz / 340 g

[DAN-Y]

A quote from BPL thread:

1L Fire Maple FMC-XK6, 1-liter, $27 with shipping, 220g / 7.8oz (hopefully including lid and handles)

Olicamp XTS 1-liter, $28.49 (Amazon Prime free shipping), 190g/6.7oz.

Optimus Terra HE .95L $31 “free shipping”, 9.7-ounce weight. While this weight is the highest, the “lid” is a whole other pot with handle and the handle on the HX pot looks to be steel and easily removable. I could imagine the HX pot only being 5.5 ounces, lidless.

[DGoggins]

I bought a Jetboil 1.8L spare pot for a winter snow melting pot. It was about $40 after 20% off deals (that backcountry/moosejaw have all the time…actually, moosejaw just had a 50% back in rewards points on cyber monday)…and 12% through activejunky.

Its actual weights are:

pot 7.22
lid 1.07
cup 1.68
cozy 1.59

I don’t plan on taking the cup or cozy…and I’m trying to find a replacement lid that fits.

[DAN-Y]

@hjuan99. interesting pot, inspired me to look it up and found this photo:

The one on the right reminded me of the pot in my original post. Heat hits the bottom of the pot first and then goes up the side heat the walls of the pot and then exits. We could remove the cozy and gain a little more heat on its way to the top of the pot ;-)

This info accompanied the pot which I got from Adventures In Stoving:

Copied from Adventures In Stoving

A Windburner will act like nothing is happening in conditions that shut a Jetboil down. Those three ounces get you a stove that will work in conditions in which a Jetboil won’t. I always bring a Windburner for desert hiking. It’s always freaking windy in the desert. The Windburner works; the Jetboil doesn’t; screw the 3.2 ounces.

A Jetboil’s heat exchanger is open. Wind can blow in one side and out the other.
A Windburner’s heat exchanger is enclosed. Air enters only through the burner and exits only through the vents.

[DAN-Y]

Look at this thing offered by Esbit to burn with an alcohol stove, Esbit CS985H-EX Cookset with Alcohol Burner and 985ml Pot with Heat Exchanger:

[Eric Blumensaadt]

I have a 2 liter JB pot W/ fins and a neoprene cozy. It could use a metal band around the outside of the fins for protection of both the fins and the cozy. Maybe a big hose clamp would help (and help increase the weight!).

I use it for winter camping for melting snow. Dunno if it is more efficient but I like to think JB would not have made the d@mn thing if not.

** P.S. When I look at my Trail Designs Sidewinder (ti Caldera Cone) and how the wide, dedicated 3 cup pot sits all the way down inside, supported by the pot rim, I think that this is about the most efficient stove system to date. Heat is forced up the pot sides to exit near the rim, utilizing most of the pot surface area to absorb heat.

SO… would a same size pot with fins on the bottom boil water faster?? (I cringe at tying to clean ESBIT crud from fins!)

[DAN-Y]

Eric, what HikingJim wrote has a lot of merit:

The Windburner works; the Jetboil doesn’t; screw the 3.2 ounces.

 

All HX pots claim 30% more efficiency, to include the ones for alcohol use.

 

 

 

[Gary Dunckel]

Four Dog Stoves sells a titanium after market lid for the Snow Peak 900 pot that is a perfect fit for the JB Sumo and MiniMo pots, as well as the MSR Titan kettle. You might want to swap out the stock wooden handle though.

[James Marco]

Generally speaking, Using adjustable low flame, a pot cozy and high efficiency wind screen, heat exchangers are wasted effort. IFF you have a system that you can put your hand on the top of the pot, it is likely extracting the maximum heat (you always need some heat differential) from your stove. With a 3.5oz pot/lid, 1qt capacity, I have hit 3/8-1/2oz fuel (older SLX…about 50/50 ethanol/methanol) consumption for two eight oz cups of water to 210 degrees F in about 9 minutes. I think the water temp was around 40-45, ie cold, but not tested. No heat exchanger, custom stove…

Anyway, a HE only extracts excess heat from a burner.  If you use a small stove and a high efficiency set-up you don’t need the extra weight of an external heat exchanger  Switching to a somewhat wider pot will do the same thing. Basically, a HE only provides increased heat absorption to a pot by increasing the lower surface area of the pot. Conceptually, you can think of an Erlienmeyer flask, or a more or less triangular shaped pot.

You can increase the speed with a larger burner and HE pot, though.

[JCH]

re: what James said – I am SHOCKED at how quickly my Soto Windmaster will boil 10 oz of water using a 900ml short/wide Toaks pot.  It is literally 3x faster than when using the 800ml Tall/narrow Toaks.  I’ve not done any measuring or timing, but there really is no question.  All of my hiking buddies are shocked when my water is boiling in 45-60 seconds.

[DAN-Y]

Ohhhh my, look at this wide bottom pot that’s calling for an alcohol stove(Fancee Feest) to be matched up with it.

[Dave Heiss]

If what James has said is true about wide bottom pots (and I believe it is true), then I wonder why nobody makes pots with a wider bottom than top? I suppose manufacturing such a pot would be more difficult, but performance-wise I think you’d get roughly the same result as with a narrow pot containing heat exchanger fins.

[David Thomas]

There are a few backpacking teakettles with wider bottoms than tops:

And you can see a few of the issues: harder to manufacture and harder to clean out (if you burn the ramen).  At least the lid is smaller and pouring from it is much easier.

[David Thomas]

As for wider versus narrower pots:

Yes, more heat is transferred into a wide-bottomed pot than a narrow bottom.

There are also more evaporative losses off a wider pot if you leave it uncovered.

Here are some dimensions of 1-liter pots (no freeboard at 1 liter so figure 800 ml usable) and their surface areas if lidless and lidded:

Diameter (cm), Height (cm), lidless surface area (cm^2), lidded area:

8, 20, 550, 600

10, 12.7, 479, 557

12, 8.8, 446, 559

14, 6.5, 440, 593

16, 5, 451, 652

18, 4, 477, 731

20, 3.2, 514, 828

If the wall thickness is constant*, then area is a proxy for weight.  A lidless pot has minimum surface area/weight when the height to width is about 0.45, although anywhere in the range of 1.3 to 0.22 is pretty close.

A lidded pot, if the lid is the same thickness has minimum surface area with height:diameter closest to 1 and in the range of 2.5 to .45.  Since most of us use lighter-than-factory lids, I’d suggest focusing on the lidless areas/weights.

*But wall thickness isn’t a constant.  As the pot diameter increases, the pot gets less stiff and easier to dent, unless you increase the wall thickness.  Consider a soda can and an aluminum pie tin.  They have similar empty weights and volumes, but the can (small diameter, fixed lid) is much stiffer than a pie tin (very large diameter, no lid).

Stove efficiency would push us towards larger-diameter pots (and some have successfully used pie tins).  Minimum pot weight would push us towards narrower pots (I’ve put heat fins on tall, energy-drink aluminum cans).

And, sometimes, like for Goldilocks, the diameter is “just right”.  If your pot nests  neatly around your water bottle or your butane canister, it takes up almost no volume and is better protected in your pack.

 

[Eric Blumensaadt]

OK Dan, you stove gurus are schooling me. I’m beginning to see that heat exchanger fins are only the first step in attaining the most thermal efficiency for a pot. It’s also that the HX fins need not only lateral shielding but venting above the fins, not beside them for the best efficiency. But is James correct that even the best designed HX pots don’t add efficiency when compared with properly proportioned pots? 

If that is true than the whole HX thing may be a mere marketing scheme. HORRORS!

My open JB fins do need at least a band around them. A big hose clamp is “vented” so it will likely work. Looks like yet another stove “science project” is in my future B/C it’s my snow melting pot.  Maybe the wood burning gassifier stoves like the Bushbuddy can put a well designed HX type pot like this to good use B/C, like my JB 2 liter pot, their pots sit on top of the stove, not down in it like my Caldera Cone style stove with the fitted 3 cup pot.

But as James said a pot that is wider than it is tall is the most efficient shape. That’s been known for a long time and exactly why I ordered my TD Sidewinder cone stove with a “wide” 3 cup pot. And even in the Inferno (gassifier) wood burning mode my pot sits down inside the cone 1/2″ which is much more efficient than a Bushbuddy stove.

[DAN-Y]

Let’s say we get the nice, right size, wide pot with HX fins. The HX will give us 30% more efficiency. Add a few more high efficiency Marco perks and we can soon disregard the added 2 ounce weight of the HX.

If we heat water 3 times a day(cold season) normally using 1 ounce of fuel for each heating using a non HX pot just think of the savings we can experience if we used a HX pot @30% efficiency savings. Almost 1 ounce of fuel by weight can be saved per day. A few days on the trail and the added weight of the HX fins is negated in alcohol fuel weight savings…….correct?

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