Fuel - how much for how long?

[Ade]

Has anyone attempted to use a chemical handwarmer, possibly inside some kind of cannister "coozie", to keep a cannister going in the cold?

 

Yes, I added a cozy and heat exchanger to a Pocket Rocket.

 

It definitely improves things but isn't as good as an XGK especially if you're cooking outside and its very cold.

 

I also carry a spare pump sometimes as this is really the only part of the XGK that can actually break. Having said that I've been using XGKs for 15 years and never had one fail completely on me.

[Mark_Husbands]

I'm wondering if adding at least some external heat source might improve a setup like that. it would seem that with a heat exchanger, as the release of gas cools the cannister and weakens the heat ouput, the exchanger itself would become increasingly inefficient at rewarming the cannister.

[Bill Slugg]

The Swiss failed on Everest in 1952 because they allowed only 3 pints of water/person/day. The British, in 1953, allowed

5 pints and were successful.

 

The heat required to melt 1 pound of snow is 144 BTU's. To raise to the boiling point (at sea level) adds another 180 BTU's.

 

MSR lists the XGK as raising 16 liters of water to boiling per 11 oz bottle of kerosene. I assume that they started with room temperature water. If they started with melted snow then it would only boil 13 liters.

 

In terms of melting snow, the same stove/fuel amount would provide 20 liters (44 pints) of 32 degree water.

 

Therefore 11 oz of fuel would provide 5 pints each for 9 people for 1 day. This is about 1.2 ounces of fuel per person per day. Bear in mind this will only provide cold drinking water, and does not provide for hot drinks or cooking.

Edited December 30, 2006 by Bill Slugg

[Ade]

Therefore 11 oz of fuel would provide 5 pints each for 9 people for 1 day.

So 11oz of fuel melts 45 pints of water? At room temperature with warm wet snow maybe, in theory. In reality 1.2oz per person isn't nearly enough.

 

I'm wondering if adding at least some external heat source might improve a setup like that.

Yes. Anything that heats the cylinder improves performance. You don't have to heat it that much just get it to a point where the gas mixture stops separating. There are various things you could try but at the end of the day you want a stove not a science project.

[joblo7]

i've used propane exclusively: simple,light, compact, easy to light.

dependable ,quiet,clean,simmers perfectly.

 

i've never used add-ons, just made it work for me. i always cook inside.i keep the can wrapped against my back in my pack and in my bag at nite, if it's super cold, otherwise i forget about it. i've used it INSIDE my sleeping bag to dry it and to warmup, on super low.

 

climbed 30+ mountains in winter 5000m+ with it.

melted and cooked at 7200m in a feezing himal ice cave for 2days. IT WORKS!

 

 

of course , for big fast pushes, big groups,or extreme cold, xgk type is better.

 

 

 

 

[Bill Slugg]

Therefore 11 oz of fuel would provide 5 pints each for 9 people for 1 day.

So 11oz of fuel melts 45 pints of water? At room temperature with warm wet snow maybe, in theory. In reality 1.2oz per person isn't nearly enough.

 

I agree. 1.2 oz is a theoretical minimum. It assumes that MSR data is correct, that the snow is at 32 deg F, that ambient temp is room temp, that you don't need hot drinks or cooked food, no fuel is spilled or evaporates, no fuel is needed to start the stove.