[pct-l] Fuel Efficiency (was: old svea)

Wed Apr 3 11:12:44 CDT 2013

Gary, 
	Yes, the ETA series is about as good as it gets. I believe that several heat exchangers were tried by various manufacturers over the years. Some use a series of ridges ground into the bottom of a pot or pan. JetBoil sort of popularized the whole thing by introducing a fairly efficient ribbon welded to the bottom of a pot, then shielding this so the "fins" would not get mashed around...perhaps the first for camping or emergency use. Optimus/FireMaple/OliCamp/MSR and several others have introduced their versions with varying degrees of success. The whole idea is to improve the convection/conduction heating of the pot and contents. Currently, I believe the MSR Reactor (much like the old Coleman camp heaters) stoves do a slightly better job, but the weight makes it prohibitive to carry. Currently, Olicamp imports from FireMaple, though I believe both are made in China, but these are 1L pots with a heat exchanger. Here is one: http://www.amazon.com/Olicamp-Hard-Anodized-XTS-1-Litre/dp/B007OJKI2U  These are about the same as the older JetBoil pots but the shield wraps around and can be used as a pot bottom on a standard stove. They fit most stoves. The problem with these is that the heat exchanger and protective shield are simply added on to the pot, reducing pot capacity and increasing overall weight. Titanium is NOT a good conductor of heat, so is not used. There have been a few problems with the newer JetBoil SolTi over the past couple years because the fins are aluminum and the pot is ti. The fins melt in any winds because the ti does not conduct it away quick enough, I believe... 
	Heat exchanger pots, HE pots, generally add about 20-40% efficiency to fuel consumption, depending on the winds. I make my own by forming a series of ridges in the bottom, about a 1/4" deep. Six ridges spreading out from the center is enough for good efficiency, around a 25% decrease in fuel consumption, and still be easy enough to clean, inside. This, roughly speaking, changes a 5-1/8" pot diameter to about 6-1/4" diameter with no increase in weight, nor, decrease in pot volume. Much like a Fresnel lens concentrates light, this type concentrates heat. My 3-3/8oz pot is still 3-3/8oz which is different from simply adding weight and reducing the volume of a pot by adding on to it. Anyway, it was just a K-Mart grease pot to start with. In a Caldera Cone, it works well by changing a 5/8+oz burn to boil 16oz to something less than a half ounce with no other changes. (I ran a series of tests -about 36 tests- several years ago and averaged them.) Esbit showed similar results, so that's the one I use these days.
	Anyway, because these are pretty independent of the heat source, whatever type of stove you are using, I don't consider this when I am doing fuel calculations. I don't base my calculations on a HE pot, either. I just use a grease pot, or, my 1.4L old one. I bought a couple ti pots and got rid of them (sold one, gave the other away.) They stick very easy when I am cooking. They do NOT conduct heat evenly. Though I never bothered to test them, I suspect they will not boil as quickly as an aluminum pot, either. Conversly, an aluminum pot will also cool off quicker and a coffee cup made of aluminum will be hotter on your lips.   
	Some current research suggests painting the bottom of your pot will help a little, black or red, I think it was. Maintaining air flow around the pot sides will help. A simple piece of aluminum draped over the pot and heat source will help. Lots of ways to capture waste BTU's from the heat source. 
	Remote canisters hold some promise because they CAN be used under a full wind screen/heat screen, much like a Caldera cone, only using a slightly more efficient fuel. 
	My thoughts only . . .
		jdm
-----Original Message-----
From: pct-l-bounces at backcountry.net [mailto:pct-l-bounces at backcountry.net] On Behalf Of gary_schenk at verizon.net
Sent: Wednesday, April 03, 2013 9:49 AM
To: pct-l at backcountry.net
Subject: Re: [pct-l] old svea

 Until it died in the Tehachapis last month, I was using a Optimus remote canister stove with a Primus ETA pot. The ETA pot has a built in heat exchanger. Using that pot and a windscreen, that stove would have water boiling crazy fast. You had to have everything ready to go before lighting that thing up, because you didn't have time to go opening dinner or looking for the tea.

It was a heavy set up perhaps, but it was mega efficient with fuel. We took a large cartridge on the JMT last year and that cartridge was good for a month. The smallest cartridge is good for a week. Of course all we did was bring water to a boil.

Actually, the big cartridge did not last the whole JMT. A friend met us in Mammoth to hike to Tuolumne and she brought a food resupply for us. She brought us quinoa! We used more fuel in two days cooking quinoa than we had used the previous week!

Gary

On 04/02/13, Diane Soini of Santa Barbara Hikes wrote:

Trailhacker has a jet boil now. The other night he used it to test out some trail meals he's working on. He got his water boiling in what seemed like 30 seconds. Talk about fuel lasting forever. Even if it takes twice or four times as long outside it's still impressively efficient. And even if there is some stove that is more efficient, I'm seriously jealous of his ability to eat hot food nearly instantly.

On Apr 2, 2013, at 10:00 AM, pct-l-request at backcountry.net wrote:

> Subject: Re: [pct-l] old svea
>
> Maybe Jim was ranting, but white gas stoves have a lot of good points. 
> The fuel lasts forever. Or it seems to anyway. White gas gives you 
> more bang for the buck than alcohol. That offsets the weight of the 
> stove somewhat. And you don't leave a line of spent cartridges in your 
> wake.
>
> Each stove set up has its plusses and minuses. YMMV
>
> Gary

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