/ How to make stoves more efficent

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bombshell - on 20 Dec 2012
Last year cooking in freezing temperatures wasted alot of fuel, anyone got any interesting tips for making cooking more efficient?
LastBoyScout on 20 Dec 2012
In reply to bombshell:

Might help if you described what your current system consists of - what stove, what pots, are you using petrol or gas, etc...
xplorer on 20 Dec 2012
In reply to bombshell:

Hand heat warmers under your gas can, if useing gas that is..
Exile - on 20 Dec 2012
In reply to bombshell:

Is it just me who had a chuckle when matching the username with the post title?
mkean - on 20 Dec 2012
In reply to Exile:
Nope me too!

Ok some tips for not wasting fuel:

- Get a heat exchanger either a pan with one fitted (Primus Etapower/Jetboil etc), an aftermarket job (MSR do one) or bodge your own (many happy hours with empty beer cans and a home made spot welder but don't blame me if you kill yourself)

- Keep the wind out; buy or make a windshield

- Get a less rubbish stove :-)

- If your stove is gas powered, has a pre-heater tube, good flame control and a remote cylinder you can try running it with the cylinder inverted which should enanble you too get more life out of a cartridge. (watch out for flare-ups!)

- Heat up your gas cartridges, different methods exist with different levels of effectiveness and different levels of risk. (NB Gas cylinders get cold in use due to adiabatic expansion so don't touch them on a cold day when the stove is running unless you want to lose skin!)...

Pre-warming the cylinders in your sleeping bag/jacket

Dipping your cylinders in your water pan as it is warming

Putting a hand warmer under the canister

Adding an "Instant death heat exchanger" (a bit of copper pipe that warms the cartridge from the flame)
Eric9Points - on 20 Dec 2012
In reply to bombshell:

http://www.spiritburner.com/fusion/showtopic.php?tid/13310/post/new/

http://www.icetrek.com/southpole/heurisko/images/c9229.jpg

The above design was optimised for fuel efficiency by a professor of thermodynamics at Nansen's request for a very efficient stove for (I think) his crossing of Greenland.
MattDTC on 20 Dec 2012
In reply to Eric9Points:

Brings back memories seeing that Primus stove!
captain paranoia - on 20 Dec 2012
In reply to mkean:

In addition to the wind protection, heat exchanger pan & pre-heat tube...

Add a lid to the pan, and even insulate the lid with a bit of Thermawrap.

When using a windscreen around a canister/pan, don't starve the burner of oxygen; either punch holes around the base of the windscreen, or leave a 2-3cm gap in the leeward side. You need about a 1cm gap between windscreen and pan, too.

But wind is the big killer, assuming your stove is working okay (i.e. you are actually getting a working pressure from your gas canister, or you have a liquid-feed stove and pre-heat tube).

Assuming a gas stove, of course...
wilkie14c - on 20 Dec 2012
In reply to bombshell: Copper wire wapped around the can a few times and then the ends sticking into the flame. Idea is that the copper conducts some flame heat to the can and aids the contents changing from liquid to gas <needs heat to do this efficiently>
Flat4matt - on 20 Dec 2012
In reply to bombshell:

Ive been carp fishing for years and aways had problems in winter with gas freezing up so got one of these which funnily enough always finds its way into my pack and acts as my winter mountaineering cook kit and works wonders at insulating it!!!!

http://www.harrissportsmail.com/Models.aspx?ModelID=18135

Ofcourse they're designed for the large canisters but if you use a smaller type and pop a handwarmer inside its the perfect set up!!!!

Im sure there's probably cheaper items out there to do the job or make one your self!!
Matt
bombshell - on 20 Dec 2012
In reply to bombshell: Brilliant thanks for all the ideas!
ice.solo - on 21 Dec 2012
In reply to bombshell:

warm the canister with body heat then insulate it AFTER to reduce cooling.

depends much on the stove: jetboils and reactors are more efficient at putting heat direct into the pot (you can put your hands right around the burner and feel minimal heat loss), but this works against you when it comes to radiant heat from the burner warming the canister (as a pocket rocket or whatever will do when placed on a reflective base with a windshield).

if sat on the ground with a reflector system and used with the adapter top to start up, jetboils work better till they get going, but it negates the whole jetboil design.

tto be said tho: i use a jet boil most of winter, way below freezing (down to -25c outside the tent), at 2200m and in hanging mode and never have problems if i warm and then insulate the canister.
i find a 225gm canister of butane/propane mix (epigas, primus, giga all seem the same) gets me about 4 days of boiling a full sumo pot (1.8L) twice, maybe 3 times a day.


subalpine - on 21 Dec 2012
In reply to bombshell: with a lid inside tent..
Solaris - on 21 Dec 2012
In reply to subalpine:

Carbon Monoxide?
Damo on 21 Dec 2012
In reply to Solaris:
> (In reply to subalpine)
>
> Carbon Monoxide?

I've spent countless months or years of my life cooking in -10C to -40C temps in a tent vestibule, zip open a bit, with not a single problem. I rarely cook totally outdoors (wind) and even more rarely have I cooked actually inside the tent, certainly not with a fuel stove, only occasionally with a Jetboil.

I do, though, regularly see people *cooking* inefficiently, regardless of the stove's 'efficiency'.
- always melt water/cook with a lid on the pot
- only *boil* what you absolutely have to, which is usually very little
- don't try to heat up/boil large volumes of cold water
- use a spoon/knife/piton/nutkey etc to constantly break up/stir ice in the pot to hasten melting
- don't leave the pot boiling for more than a few seconds, if at all - don't leave water steaming away or meals bubbling etc while everyone stands around talking, blogging etc
- cooking/making water is an important full-time job on a cold expedition, not a chore on the side, so should be treated as such
- suit the cooking to the location/climb. Maybe take food that does not need cooking at all. Take less fuel of no snowmelting is required.

I 2nd Mr Solo's point about insulating *after* warming. I think it was AndyK made a point years ago about insulating jackets actually keeping the cold IN against the canister if not heated before.
ice.solo - on 21 Dec 2012
In reply to bombshell:

yeah, agree with damo re carbon monoxide - with basic attention its avoidable.

i find having the stove hanging reduce further CO issues as its above your head (CO sits on air) so is also easily reduced by the warmth rising from your body, and most tents have vents up high.

on the same theme not go to boil: aside from wasting fuel, it means drinks take longer to cool therefore more time being rested on the floor and prone to being spilled, as well as steam compromising your tents environment to cause issues later.

i like cooking actually in the tent as it captures a degree of heat - but has obvious implications re gasses, flammability etc, narrowing things down to pretty much jetboils (even reactors worry me).

worth looking at are the newish soto muka stoves - been using one this winter and very impressed. no priming and flares minimal enough to either be fine in large tents, or only needs holding outside for about 15 seconds.
because theres no soot involved, the initial flare can be sorted with the pot on the stove (i use a reactor pot with the built in flux feature to further capture heat).
nniff - on 21 Dec 2012
In reply to blanchie14c:
> (In reply to bombshell) Copper wire wapped around the can a few times and then the ends sticking into the flame. Idea is that the copper conducts some flame heat to the can and aids the contents changing from liquid to gas <needs heat to do this efficiently>



Or a piece of copper pipe hammered flat with a circular piece of wire to hold it onto the cylinder. Beware - it gets seriously hot all the way down if it's actually in the flame. My mark one version had two small magnets set in holes in one side of double thickness sheet, so that it would just stick to the cylinder. I've yet to find glue that can cope with the heat, so a bit of wire works instead.
Solaris - on 21 Dec 2012
In reply to Damo:

Knowing (via UKC and your guidebook), and respecting hugely your experience, I'm not challenging your post, but will make a few points:

1) a lot seems to depend on burner design.
2) Experienced people have got into very serious trouble owing to CO.
3) Paul Ramsden concludes what looks to me (I'm not a scientist) a thorough and well-researched article in the latest AJ thus:
"I am convinced that many of the well-known incidents at high altitude involving poor decision making, poor route choice and incorrect use of equipment or individuals making unexplained mistakes are potentially caused, or at the very least contributed to, by CO poisoning and not necessarily just due to altitude as we often say."

That said, Ramsden praises the Reactor very highly, despite the risks associated with using it, but he does add: "Cook outside if you can; if cooking in the tent, keep it well ventilated and be extra careful of nodding off while cooking" - which your second to last point reinforces.
Jim Lancs - on 21 Dec 2012
In addition; it's worth going to any effort to find water and not just assume that melting snow is the best option. Dig for water where you can.

When using white gas and an MSR Dragonfly, we found that the MSR heat exchanger didn't save enough fuel to warrant the weight of carrying it when being resupplied every 12 days. The same weight in extra fuel was more weight efficient.
mkean - on 21 Dec 2012
In reply to Damo:
Insulating the cylinder is a bit of a balancing act, as the pressure drop as you cook is quite effective at cooling it. Adiabatic expansion is used for super cooling high efficiency thermal cameras with good reason ;-)
Heat the thing up nicely before hand and don't bother insulating the cylinder unless it is properly baltic!

Anyone know what the maximum safe pressure for a standard cylinder is?
ads.ukclimbing.com
Scott - on 21 Dec 2012
In reply to bombshell:
After being out camping a couple of times in sub-zero last winter, I've now abandoned my gas stove and now just use the little 'army-type' fold up metal stand with the little fuel tablets- cheap, stable and more lightweight, compact and reliable than a gas set-up in all weather conditions. I'm now not left guessing how much gas I've got left and if I do run out of tablets, you can use twigs/ sticks etc on it- or even meths (from a local garage that didn't sell gas)soaked rags and still cook.
roy-w - on 21 Dec 2012
In reply to Scott:

http://gearthirty.blogspot.be/2012/03/alpine-bomb-for-msr-reactor.html

works great but keep a aye on the heat of the can

roy

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