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*MODIFYING STOVES, COOKING IN TENTS, FIDDLING WITH THERMAL CAPTURE AND MESSING WITH GAS MIXTURES – THE FOLLOWING ARTICLE HAS IT ALL. THINK WHERE YOU ARE. THINK WHAT YOU’RE DOING.  ENTER AT YOUR OWN RISK

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THERE ARE NO TRUE STOVES FOR HIGH ALTITUDE ALPINISM, WHICH MEANS YOU HAVE TO MODIFY THEM, SO IF YOU ARE NOT DOING THIS YOU ARE BLOWING A FUNDAMENTAL PART OF UNLOCKING THE POTENTIAL OF HI ALT CLIMBING WHICH IS STAYING HIGHER TO GET STUFF DONE. EVOLVING EXPEDITION ALPINISM MEANS TARGETING SEVERAL THINGS, PARTICULARLY THE REDEFINITION OF WHAT CAMPS ARE AND HOW THEY ARE PLACED STRATEGICALLY. UNSUPPORTED TEAMS DON’T HAVE THE LUXURY OF THE LARGE BASE CAMPS ASSOCIATED WITH HIGH ALTITUDE CLIMBING WHICH MEANS THEY DON’T HAVE THE KITCHENS THAT GO WITH THEM, RESHUFFLING THE POSITION OF STOVES UP THE MOUNTAIN.

ALPINE EXPEDITION TEAMS DON’T DROP BACK TO BASE CAMP FOR ‘PROPER’ MEALS WHICH ALLOW TIME UP HIGH TO BE DONE ON MINIMAL ROTATIONS KNOWING A CATERED MESS TENT AWAITS. INSTEAD, REAL FOOD GOES FURTHER UP THE ASCENT – EFFECTIVELY AS FAR AS YOU CAN MAKE IT. AS THINGS EVOLVE TO BE LIGHTER AND MORE ALTITUDE-RESISTANT THINGS CAN GO HIGHER, WITH NEW STOVE COMBINATIONS PUTTING OUT EFFICIENT POWER NOW AT ALTITUDES WAY BEYOND THE LIMITS OF NOT LONG AGO.

YOU WILL SURVIVE A NIGHT OR TWO WITH SOMETHING PUNY LIKE A JETBOIL, MELTING JUST ENOUGH TO REHYDRATE, AS THIS IS FINE WHEN THERE’S AN UMBILICAL BACK TO LARGER CAMPS, BUT IT WON’T GET FAR FOR SERIOUS LIVING, UNSUPPORTED, FOR WEEKS, AND IS USELESSLY INEFFICIENT FOR A TEAM. OTHER STOVES APPROACH WHAT’S NEEDED BUT ALL HAVE MAJOR DEFICIENCIES, RANGING FROM WEIGHT, TO ENERGY OUTPUT, EFFICIENCY AND INTERFACE. 

IT HELPS HERE TO DEFINE THE THERMAL FLOW INVOLVED, WHICH CONSISTS OF MAKING HEAT, STABILIZING HEAT, TRANSFERRING HEAT THEN CONTAINING HEAT, AND HAVING DEVICES THAT ADDRESS EACH PHASE AS EFFICIENTLY AS POSSIBLE.

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WHAT WE DO

WE MODIFY OUR ALREADY EXISTING POWERFUL FUEL STOVES, TO ADAPT TO THE UNIQUE DEMANDS OF HIGH ALTITUDE IN LATE AUTUMN AND WINTER. EVEN THE BEST OFF-THE-SHELF MODELS STRUGGLE AT -30c AND ALTITUDES AT +6000m, BUT WITH SMART MODIFICATION CAN BECOME FUTURISTIC AND OPEN UP WHAT CAN BE DONE ON A MOUNTAIN.

WE RARELY FIDDLE WITH THE GAS SYSTEM ITSELF, HALF BECAUSE THAT NEEDS SERIOUS TOOLING AND KNOWLEDGE, BUT ALSO BECAUSE THAT’S NOT REALLY WHERE THE PROBLEMS ARE. CHANGE A STOVE ALL YOU WANT BUT THE ENVIRONMENT STILL DICTATES WHAT HAPPENS TO THE GAS THAT COMES OUT, WHICH IS IMPOSSIBLE TO ADDRESS TOTALLY FROM A COMMERCIAL POSITION. WE WANT STOVES THAT ADAPT AS WE GO UP AND DOWN, ACROSS DIFFERENT TEMPERATURE RANGES, AND FOR DIFFERENT TEAMS AND TYPE OF CLIMBING, THUS WE BASE OF STOVES THAT WORK PERFECTLY FINE IN A HOTEL ROOM WITH NO ADAPTIONS, THEN CAN BE BLINGED OUT FOR OPEN BIVIES IN CONDITIONS WHERE THE STOVE IS WHAT KEEPS US ALIVE.

WHETHER YOU DO WHAT WE DO IS NO ONES JUDGMENT BUT YOUR OWN, BUT THIS IS WHAT WE USE ON TRIPS TO PLACES LIKE TIBET AND THE KUNLUN IN WINTER. TO PARAPHRASE HUNTER S THOMPSON “WE HATE TO ADVOCATE MODIFICATION, DO-IT-YOURSELF PARTS, CUTTING BITS OFF AND REASSEMBLING STOVES IN WEIRD WAYS TO ANYBODY – BUT IT’S ALWAYS WORKED FOR US”.

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RAW POWER

HIGH ALTITUDE STOVES NEED TO BE POWERFUL BECAUSE THEY WILL WORK HARD TURNING ICE TO WATER. WHATEVER EXTRA JUICE THEY NEED IS WORTH IT IN TIME SAVED, AND WHEN PUSHING AGAINST CONDITIONS THAT COMBINE WIND, COLD, LOW PRESSURE AND VOLUME. WE REGARD ANY STOVE PUTTING OUT LESS THAN 3000kcals TO BE A WASTE OF TIME, AND OURSELVES USE A 4000kcal STOVE. WHILST A FEW INVERTABLE CANISTER STOVES WILL JUUUUUST GET YOU 3000kcals (3200 IF YOU KNOW WHAT TO LOOK FOR) IT TAKES FUEL TO GET THE FULL 4000.

ANYONE WITH EVEN A GLANCE AT SUCH THINGS KNOWS THIS MEANS STOVE WITH GENERATOR TUBES, THAT EITHER HEAT GAS PASSING THROUGH OR THE STOVE FLUX ITSELF.

THE DIFFERENCE WITH 4000kcals IS MEASURED IN TIME, MOST NOTICEABLE WHEN IT COMES TO MELTING ICE AND WITH SITTING IN THE COLD. 4000kcals KNOCKS ABOUT TEN MINUTES OFF EVERY FIVE KILOS OF ICE, WHICH ADDS UP TO HOURS ACROSS DAYS. NOT EVERY POT IS MADE TO HANDLE THIS SORT OF POWER, BUT AS THIS A TEAM STOVE BY DEFAULT POT VOLUMES ARE LARGER AND SO HAVE MORE ROBUST MATERIALS. 4000kcals CAN ALSO OVERWHELM TINY LITTLE POTS BY HEAT RUNNING UP THE SIDES, MELTING HANDLES AND NOT ALLOWING THE BURNER TO BE USED AT OPTIMAL EFFICIENCY.

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HEAT EXCHANGERS

IT IS WARPED LOGIC TO HAVE POWERFUL STOVES BUT NOT CAPTURE THE ENERGY BY LETTING IT BLEED AWAY DUE TO THE LIMITATIONS OF THE USUAL EXCHANGERS FOUND IN THE SHOPS. YES, THERE ARE SOME NICE DESIGNS GETTING AROUND THAT WORK WELL FOR SMALL STOVES OF THE SORT USED INSIDE TENTS, BUT VERY FEW EITHER HANDLE REAL POWER OR MAKE THE MOST OF IT WHEN THEY DO.

PROPER HEAT EXCHANGERS ARE THINGS THAT CAPTURE ENERGY, THEN USE IT TO SHIFT THAT ENERGY FROM ONE MASS TO ANOTHER – IN THIS CASE CAPTURE THE HOT GAS FROM THE STOVE AND GETTING INTO THE CONTENTS OF YOUR POT. IN A BASIC WAY SIMPLY THE METAL OF THE POT IS A HEAT EXCHANGER, AS IT ABSORBS AND TRANSMITS THERMAL ENERGY AS A BRIDGE BETWEEN GAS THE LIQUID. UNDERSTANDING THIS ILLUMINATES WHERE PURSUING METALS IN THIS PHASE TRANSITION FITS IN.

A PROPER HEAT EXCHANGER IN THIS CASE IS A SHAPED PIECE OF METAL, THAT COLLECTS LOTS OF HEAT THAT THEN CREATES A HOT AIR MASS AROUND IT FOR FUEL TO FULLY COMBUST AND PASS INTO THE POTS BASE, ESPECIALLY IN RELATION TO EXTREMELY COLD TEMPERATURES AROUND IT THAT SPEED UP THERMAL DISSIPATION. METALS LIKE COPPER CAPTURE A LOT OF HEAT AND ARE EASY TO SHAPE, AND HAVE A LONG HISTORY AS EXCHANGERS FOR WARMING CANISTERS etc. USED AS MESH, EXCHANGERS COMBINE AIR FLOW AND ALLOW DIRECTED BURNER CONTACT, IGNITING AND CONTAINING A LOT OF HEAT AS WELL AS SOME INFRARED RADIATION. 

YES YOU CAN STACK AN EXCHANGER POT ONTO A STOVE WITH AN INDEPENDENT EXCHANGER ON IT, BUT THE MAIN THING HERE IS THAT ANY POT NOW USES THE EXCHANGER, WHICH CAN BE BETTER DESIGNED BECAUSE IT NEEDN’T FUNCTION AS A POT BASE. POT-EXCHANGER INTERFACE HERE IS CRITICAL, AND NEEDS TO BE AS SEAMLESS AS POSSIBLE, WITH GOOD METAL-TO-METAL CONTACT.

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FLUX RINGS

FLUX RINGS ARE A DIFFERENT FORM OF HEAT EXCHANGERS, AND THE CORRUGATED THING AROUND THE RIM OF YOUR POT HAS MORE TO DO WITH STABILIZING A PILLOW OF AIR – HEATING IT AS IT IS DIRECTED IN, REDUCING IT BLOWING AWAY, AND TRANSMITTING SOME HEAT THROUGH THE METAL IN A FAIRLY MINIMAL WAY. THEIR PRIMARY FUNCTION IS CREATING A HOT SPACE SO FUEL CAN VAPORIZE EFFICIENTLY, WHICH ALONE MAKES A BIG DIFFERENCE BUT WHICH IS ONLY HALF THE STORY, AND HALF THAT FINDS ITS LIMITS AS THINGS GET VERY COLD, VERY HIGH AND OUTPUT DEMANDS SOAR.

FLUX RINGS ARE STILL PRIMITIVE IN CAMP STOVES COMPARED TO WHAT COULD BE GOING ON BASED ON OTHER INDUSTRIES WHERE THE CONCEPTS AND APPLICATIONS ARE SOPHISTICATED. THE AVERAGE STOVE USER BOILING A LITER OF WATER AT LOWER ALTITUDES HAS LITTLE NEED TO PUSH EFFICIENCY, BUT A TEAM IN EXTREME COLD ON A REMOTE PEAK MELTING AND COOKING FOR WEEKS SEES VERY REAL BENEFITS TO GETTING THINGS TUNED. 

LOSS OF THERMAL ENERGY THROUGH CONVECTION (WIND) IS STANDARD STUFF, BUT THE NEED FOR AIR INPUT IS VITAL FOR STABLE HEAT. FLUX RINGS ARE THE REQUIREMENT HERE AS THEY ALLOW 360o INFLOW BUT PROTECT FROM DIRECT WIND, AND ARE EASILY MODIFIED TO SHIELD ONLY FROM THE REQUIRED DIRECTION. THE BEST FLUX RINGS HAVE VANES THAT CHANNEL AND WARM AIR, THAT LEAD SEAMLESSLY INTO THE EXCHANGERS THAT HEAT THEM. SOME FLUX RINGS IN COMMERCIAL COOKWARE SPIRAL, INCREASING THE SURFACE AREA FURTHER, AND A DEGREE OF VORTEX IN THE CENTER AIR MASS THAT DYNAMIZES PRESSURE LIKE A JET ENGINE, BUT HOW MUCH EFFECT THIS HAS AT THE CAMP STOVE LEVEL NEEDS MORE SOPHISTICATION THAN WE HAVE TO QUANTIFY.

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WINDSHIELDS

GOOD FLUX RINGS DO PART OF THE JOB OF WINDSHIELDS BY REDUCING RANDOM WIND CURRENTS, BUT DON’T DO ENOUGH WHEN THE WIND IS STRONG FROM ONE DIRECTION. ENCAPSULATED SYSTEMS LIKE THIS, ESPECIALLY FOR USE IN PRECARIOUS PLACES, DON’T RELY ON FLIMSY SHEETS OF ALUMINIUM THAT SIMPLY REST AROUND A STOVE LIKE YOU MIGHT GET AWAY WITH ON A PICNIC TABLE, LIKEWISE THEY DON’T NEED THE BULKY TUB SHIELDS TRANGIAS AND THE OLD MARHILLS USED.

WHEN EXCHANGERS AND FLUX RINGS ARE DONE RIGHT, A WINDSHIELD NEED ONLY DIVERT WIND FROM THE EXPOSED SIDE ENTERING THE FLUX VANES, AND FROM COOLING THE STOVE BODY BY CONVECTION. WE USE A SIMPLE TITANIUM PIECE THAT DROPS INTO PLACE, AND FITS TO ANY SIDE OF THE STOVE EASILY, HELD IN PLACE BY THE FLUX RING.

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REFLECTORS

REFLECTORS NEED TO BE PROPERLY UNDERSTOOD TO WORK – SOMETHING NOT ALWAYS SEEN. REFLECTIVITY OF THERMAL RADIATION ONLY WORKS WHEN THERE IS NO CONTACT WITH THE HEAT SOURCE, BECAUSE IF THERE THE (USUALLY METALICIZED) MATERIAL THEN CONDUCTS. THIS MEANS YOUR HEAT EXCHANGER DOESN’T REALLY WORK AS A REFLECTOR BECAUSE IT’S FUNCTION IS TO CONDUCT, AND SO HAVING AN EXCHANGER IN CONTACT WITH A REFLECTOR THEN ACTS AS A THERMAL BRIDGE. THERE IS A PLACE FOR THIS (SEE BELOW) BUT IT IS NOT THE CASE IN THIS PART OF THE THERMAL FLOW.

REFLECTORS HERE ARE PART OF THE STABILIZING HEAT PHASE, THAT MOP UP THERMAL RADIATION AND DIRECT IT BACK TO HELP FUEL COMBUST AND TO TRANSFER IT INTO THE POTS BASE. HIGH REFLECTIVE INDEX METAL LIKE TITANIUM DOES A GOOD JOB OF THIS, PLACED AROUND THE BASE OF THE STOVE AND ANGLED TOWARDS THE HEAT EXCHANGER. THOSE ALUMINIUM SHEETS THAT STOVES SIT ON DO A RUDIMENTARY VERSION OF THIS, BUT BECAUSE YOU CAN SEE THE GLOW OF THE STOVE REFLECTED OFF, MUCH OF THE RADIANT HEAT IS TOO.

GOOD REFLECTORS WILL APPEAR BRIGHT LIKE ONE OF THOSE CAR WINDSHIELD BARRIERS, AND SHOULD ENCAPSULATE THE SPACE AROUND THE STOVE WITH VERY LITTLE LIGHT BLEED. COPPER IS GOOD BUT RELATIVELY HEAVY, AND TITANIUM HITS ABOUT THE BEST BALANCE, BEING LESS PRONE TO SURFACE CORROSION THAN ALUMINIUM. IT NEEDS TO SUSPEND DOWNWARDS FROM THE HEATED SOURCE, NOT SIT ON COLD GROUND, TO MINIMIZE THE THERMAL BRIDGING THAT MAKES MOST ‘REFLECTORS’ ACTUALLY WINDSHIELDS.

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THERMAL MODIFIERS

ONCE YOU PRODUCE THE HEAT, CAPTURE IT, SHIELD IT, THEN DIRECT IT INTO THE POT, IT IS INSANE TO THEN LET IT CONVECT AWAY BOTH WHILST COOKING OR ONCE YOUR ICE HAS MELTED. THERMAL MODIFIERS ARE OFTEN CALLED ‘COSIES’ WHICH SOUNDS LIKE SOMETHING YOUR GRANDMOTHER HAS AND BELIES HOW CRITICAL THE DEVICE IS HERE. IN A WAY MODIFERS ARE THE OPPOSITE OF HEAT EXCHANGERS – THEY RETARD THE TRANSITION OF ENERGY – BY FORMING A LAYER OF STILL AIR AROUND THE POT THAT RESISTS THE MOVEMENT OF HEAT OUT INTO THE COLD ENVIRONMENT.

THE BEST MODIFIERS CREATE A WARM LAYER THAT INSULATES THE POT, THEN IS FURTHER INSULATED ITSELF TO MINIMIZE CONVECTION. THIS IS DONE BY PICKING UP SOME HEAT FROM THE POT VIA CONDUCTION, AND TRAPPING IT WITH INSULATION THAT HANDLES THE TEMPERATURES. A DEGREE OF AIR MOVEMENT IS NEEDED TO STOP YOUR POT BECOMING OVERHEATED (ESPECIALLY PRESSURE COOKERS, MORE BELOW), BUT THIS SHOULD BE VERTICALLY TO AVOID THE EFFECTS OF WIND.

MODIFIERS WE USE COMBINE TITANIUM AND NEOPRENE, PICKING UP SOME HEAT VIA THE THERMAL BRIDGE ACTION WITH THE TITANIUM THEN INSULATING IT WITH NEOPRENE TO REDUCE HEAT LOSS WHILST COOKING/MELTING TO THE TUNE OF ABOUT A 20% INCREASED EFFICIENCY WITH BOIL TIMES (A VERY SKEWED METRIC ON HIGH COLD MOUNTAINS, BUT YOU GET THE IDEA). IF YOU DID NOTHING ELSE, THIS IS PROBABLY THE BIGGEST EFFECT THERMALLY, AND WHY NO DECENT COMMERCIAL VERSIONS HAVE BEEN PURSUED IS SIMPLY BIZARRE.

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BASEBOARDS

ALL POWERFUL STOVES NEED A BASEBOARD, TO ACT AS A THERMAL BARRIER, FOR STABILITY AND ALLOW ALL THE OTHER PARTS TO ALIGN IN PLACE. MODIFICATIONS TO STOVES INCREASE THE RESPONSIBILITY FOR GETTING EVERYTHING RIGHT REPEATEDLY, AND THE LAST THING YOU WANT ARE ALL THE VARIABLES THAT COME WITH DIFFERENT SURFACES. THE BASEBOARD WE USE IS A SPECIAL ONE FROM ELITECLIMB, MADE WITH MATERIALS DESIGNED FOR HIGH HEAT AND CUT TO FIT THE FEATURES WE NEED. BASEBOARDS NEED TO HOLD ALL MANNER OF FUEL BOTTLES, STOVES AND THINGS LIKE REFLECTORS, AND SHOULD HAVE WAYS TO ATTACH LIGHTERS, AND BITS OF CUTLERY THAT GET USED ALL THE TIME.

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POTS

GOOD POTS ARE HARD TO COME BY, AT THE VOLUME REQUIRED, WITH DECENT HANDLES, DURABILITY AND WEIGHT, AND WE HAVE BURNED THROUGH A LOT OF POTS ALONG THE WAY, BEFORE SETTLING ON WHAT WE NOW USE.

EASILY THE BEST POTS COMMONLY FOUND ARE THE MSR REACTOR POTS, AND WHILST THE STOVE ITSELF IS UNDERWHELMING, THE POT IS ONLY ONE OUT THERE THAT GETS THE EXCHANGER, FLUX RING AND TO SOME DEGREE THE MODIFIER RIGHT. AS A SECOND POT THESE ARE WORTH CARRYING

AS A MAIN POT FOUR LITER ONES ABOUND, SOME HAVING BUILT IN FLUX RINGS, BUT THE ULTIMATE POT ARE THE ULTRALIGHT PRESSURE POTS COMING OUT OF KOREA, WHICH TOTALLY CHANGE COOKING AND MELTING AT HIGH ALTITUDE. THE FUNCTION OF THE PRESSURE ASPECT WE WILL ADDRESS IN DEPTH SOON – ONLY TO SAY THEY WORK, THEY WORK BRILLIANTLY, AND THERE’S NO GOING BACK AFTER – BUT SAY NOW THAT THE FUEL SAVED EASILY JUSTIFIES THEIR WEIGHT (AND THEY’RE NOT VERY HEAVY), AND THEY WORK IN SEAMLESSLY WITH EXCHANGERS, MODIFIERS etc TO MAKE A SYSTEM NEVER BEFORE AVAILABLE HIGH ON MOUNTAINS.

PRESSURE POTS OBVIOUSLY WORK AS NORMAL POTS TOO, AND CAN BE FITTED OUT WITH THERMAL MODIFIERS ROUND THE SIDES AND SIT DIRECTLY ONTO INDEPENDENT EXCHANGERS AND FLUX RINGS. THIS ALL WARRANTS CARE DOWN LOW WHERE TEMPERATURES AND PRESSURES GET HIGH FAST, AND WE OFFER NO EXPERIENCE IN CONDITIONS LIKE THE POLAR REGIONS WHERE ALTITUDE IS NOT MUCH OF AN ISSUE.

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STOVES MODIFIED WITH ALL THIS ARE NOT STOVES FOR LOW ALTITUDE OR WARM CONDITIONS AS THEY BUILD UP TOO MUCH HEAT AND BECOME A SERIOUS RISK. FOR THIS REASON WE HAVE ALL THESE PARTS REMOVABLE, FITTING WHAT IS NEEDED AS CONDITIONS ALLOW, WHICH BRINGS IT’S OWN DESIGN DEMANDS OF HAVING THINGS EASILY INSTALLED AND LIGHT TO CARRY. WE NEED THINGS TO ALL STACK INTO THE POT (EXCEPT THE BASE BOARD) AND OF COURSE TO BE LIGHT.

THE FULL ENSEMBLE DISCUSSED ABOVE WEIGHS ABOUT 700g WITHOUT POTS AND FUEL, AND RECALL THIS IS A TEAM WORKHORSE STOVE SET, THAT WILL KEEP UP TO SIX CLIMBERS IN FOOD AND WATER FOR WEEKS ON END IN THE WORLDS HIGHEST AND COLDEST ENVIRONMENTS.  

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