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Elevation and stoves


olyclimber

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You're asking a question that depends on two factors.

 

1. The space you have to cook in

2. The temperature at cooking time.

 

In general I'd take a canister stove in the summer or whenever I was cooking on a non snow surface. In cold temperatures the isobutane canisters will burn the butane first and then the propane, so for half the life of the canister the stove will rock but it will suck for the last half.

 

If you're going out in the winter and you have space for a white gas stove, take it. Likewise if you're climbing at higher elevation and it's winterlike then take the white gas stove as long as you have cooking space.

 

If you're climbing a route with tiny ledges and you have to camp out then the gas canister stove may well be a better option no matter what the altitude.

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Ive had trouble with canister stoves as warm as 30degrees. I've heard of having 2 canisters and keeping one warm while you use the other, and then switching when it becomes to cold. Also heard about taping hand warmers to the canister. Both seem like a pain in the ass. If you have the option, go with a liquid fuel stove that pre-heats the fuel (eg. MSR whisperlight), if you plan on being in a cold area.

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In cold temperatures the isobutane canisters will burn the butane first and then the propane,

 

Not to pick nits but isobutane is NOT a mix of butane and propane. Isobutane is a branched isomer of butane, both having the same chemical formula. This molecular structure allows it to volatilize at lower temperatures than regular butane.

 

To answer the original question we should look to Boyle's Law which states (and I paraphrase here) that the vapor point is based on temperature and atmospheric pressure. The higher the altitude (lower pressure) the colder it can be and still have the fuel volatilize. Isobutane may not volatilize at 0 F at sea level, but volatilize at 0 F at 20,000 ft. In short, it has everything to due with elevation and temperature.

 

As someone mentioned previously, there are some tricks to getting a cansister stove to work in the cold. The simplest and most effective is to use a foil wind screen. This will deflect enough heat onto the canister to keep it running. Sleep with the cansister to keep it warm for the morning too.

 

In practical terms, however, I think AlpineK nailed it on the head. In summer I bring a canister stove, in winter and Alaska I bring a liquid fuel stove.

 

 

Edited by danielpatricksmith
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As DanielPatrickSmith stated it does have to do with both temperature AND elevation...but the pressure inside the canister is only affected by the temperature of the can which affects the vapor pressure of the iso-butane. The higher the can temperature, the higher the vapor pressure. the flame strenght (assuming the orrifice is the same) is proportional to the delta P (or difference between the can pressure and the atmospheric pressure). So this means that the higher the elevation the better a can stove burns...

 

Let me repeat this - canister stoves work BETTER at elevation if the temperature of the fuel is equal. I ran out of iso-butane fuel at a 4 day camp at just under 20,000 feet and continued to use some straight propane canisters that I had as a back-up. They worked just fine. I suspect that at sea-level they would have been problimatic. I do, however, have a few tricks to keep the fuel warm.

 

Temperature certainly affects the flame more than going higher, but you do get a significant advantage at elevation. The only reason that a partial can seems to lose power faster than an almost full can is because the loss of heat of evaporation of the fuel volitizing inside the can has a much lower volume of liquid to cool down. If you can keep the little bit thats left from getting cold it will burn bright and full to the last sputter.

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DPS, not to nit-pick, but you are wrong in practical terms about gas fuel bieng a mix. Sinsu-stricto iso-butane is a pure gas, but MSR markets their cannisters as a mix of propane and butane. So in reality, Kurt is right, and you are a dumb son of a bitch.

I had to check the MSR canister and you are indeed correct. You needn't be mean about it though. cry.gif

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I like this thread of discussion... thumbs_up.gif

 

On Denali we used XGK stoves. We were having trouble with them at the 17,200ft, the high camp. Our stove would just not keep the flame going and would put itself out. It was not too terribly cold and we were preheating the nozzle and the burner. Parts were well maintained, so that was not an issue.

 

Then, we received a suggestion from the Rednecks (Ryland Moore and Pete A) that keeping the bottle pressure low and pumping the stove just enough to keep the fuel flowing solves the problem. That suggestion worked, even though it meant a longer time with the kitchen duties, and more babysitting.

 

I speculate that this solution had to do with the adiabatic expansion of the compressed fuel, quickly cooling itself/burner, putting the flame out. Lower pressure meant slower escape from the nozzle??? Physicists will no doubt have an explanation...

 

What's clear is that I will have to call high altitude climber friends to hear their solutions before I head out to higher elevations. White gas or canister, then which type of canister, etc...

 

Erden.

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I have always thought that stoves in Alaska worked poorly because the fuel was old. When you buy it from the flight service, you can't tell how long it has been sitting around. We had difficulty with stoves in the past, which then worked well when the fuel source was changed to a known "good". I don't think that cooling from evaporation could cool any reaction with such a high heat of reaction as the proper combustion of a fossil fuel, such as in a stove, to have a deleterous effect on combustion.

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Actually evaporation does have an effect with the burning efficiency of the canister stoves. Out in icy conditions the canisters will ice over from the evaporation in them if they are not heated from an exterior source. I have a Markil Hanging pot setup that did piss poor out in snowy conditions. But when used inside the tent where the heat from the stove warmed up the tent the Markil burned like a champ.

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I don't think that cooling from evaporation could cool any reaction with such a high heat of reaction as the proper combustion of a fossil fuel, such as in a stove, to have a deleterous effect on combustion.

 

The heat of combustion outside the canister has nothing do do with the evaporative cooling inside the canister. Unless, of course, you manage to get a fire going inside the can, which I think is a bad idea. Give it a try crazyjz and let me know how it works out for you.

 

Propane has even been used as a refrigerant gas. It sucks a whole lot of heat when the liquid evaporates inside the canister.

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I was refering to Erden query about adaibatic cooling of the flame. A careful reading of that post would show that that particular question was in regards to evaporation in the burner area, on a liquid fuel stove.

 

After years at a mechanical fab shop, I know all about the evaporation in the gaseous portion of propane, liquid oxygen, etc bottles.

Edited by crazyjz
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