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Heat Exchanger For (Ant)arctic Explorers

Because humans suffer from poor thermal management.
  [vote for,

Cold weather is hostile, to most humans at least, although some peoples have adapted well to extreme environments. In the US, there are people living far north of the arctic circle where even the most enthusiastic of pizza menu delivery people dare not tread. Nevertheless, there are still environments too extreme for all but the most intrepid/daft humans. The depths of the Antarctic continent have punishing low temperatures, extreme winds, high altitudes, and formidable physical barriers. As such, people who find themselves there, tend to hunker down in research stations and apparently, drink an awful lot through the winter. Nevertheless, there are people who dream of the last remaining feats of exploration.

One such feat is a solo, unsupported transantarctic trek*. This is particularly tricky. Since the antarctic is big, cold, high and undulating, you need quite a lot of equipment. Significant clothing for insulation, additional sturdy tents and super thick sleeping bags, again for insulation. Fuel, to melt water and cook food and then the actual food. Lots of food. This is the only real energy source for the person doing all the moving and staying warm. This all has to be hauled along, usually on a sled. This is where the compromises creep in. You can take less stuff, and move faster, but should you be stuck in a storm you may run out of resources waiting and be unable to complete the trek. Or, you can take a lot, and move slower, sapping morale and increasing the likelihood of encountering a storm.

The energy needed to move is pretty invariant, humans tend to be similarly efficient. What remains is the fuel for cooking/water and the energy required to keep warm. Now, people with more motivation than brains have discovered that a diet high in fat** gets you a lot of dense calories, minimizing the excess weight, but we can do better.

There's quite a lot of research on how much heat people lose in cold environments, a reasonable example <link> suggests that at -40C up to 20% of working and 30% of resting metabolism is expelled with normal breathing. That is a large amount. And -40C is child's play compared to the temperatures and wind chill that a modest 5 day antarctic storm can dish out.

So, we solve it. Breathing in cold air, heating it up and humidifying it in the lungs and then breathing it out to the antarctic environment is a stupid waste of energy. So, lets breath through a heat exchanger. This can be a super simple device. Essentially a mouthpiece, a pair of counter current- arrangement tubes and a little flappy valve or two. The best arrangement will be a central tube with a spiral arrangement around the outside. Breath in through one, out through the other with the valve ensuring unidirectional flow. The system should have a couple of lungfuls of dead volume, this gives the air a few seconds to dwell and exchange temperature. Now, the air you breath out will warm the air coming in. You save an awful lot of heat.

The by product is a bit of condensed water, this should be collected and may be drunk at (slightly disgusting) leisure.

Now, there is prior art <link> but this is just some "media" read "stuff" that gets warmed during exhale and cooled during inhale. Similar principle but nowhere near as efficient as a proper heat exchanger. If they wanted to do a better job, the "media" should be thin tubes containing a eutectic substance at an appropriate temperature, although that would be difficult to get exactly right depending upon conditions.

* When that's been conquered, it will be a solo unsupported trek over the long axis, then in winter... until there are no people left who will sponsor such increasingly tenuous connections to unique achievement.

** fancy pants explorers with their fussy requirement for a separate fuel from their stove. Swap in the winter mix of my single battlefield fuel for extra efficiency.

bs0u0155, Feb 13 2017

Heat loss in cold temperatures https://www.ncbi.nl....gov/pubmed/2336491
[bs0u0155, Feb 13 2017]

Heat exchange mask https://www.amazon....7X8J0DQPP90W1XXYM70
[bs0u0155, Feb 13 2017]

Single Battlefield Fuel Single_20Battlefield_20Fuel
Add extra glycerol for winter. [bs0u0155, Feb 13 2017]

Sweat purifier. http://gizmodo.com/...till-suit-826806326
I imagine it could be used for exhaled moisture as well. [2 fries shy of a happy meal, Feb 14 2017]

Stillsuit http://dune.wikia.com/wiki/Stillsuit
Dune [8th of 7, Feb 14 2017]

All those 5 day storms contain a huge amount of energy Bask_20in_20the_20Antarctic_20breeze
[TIB, Feb 15 2017]


       I always thought the basic problem was low body mass, high surface area and having six spindly legs.
MaxwellBuchanan, Feb 13 2017

       //the Formicidae represent between 15-25% of the earth's biomass//   

       That has to be wrong. That would mean that for every blade of grass, there's several ants. For every tree, a pile of ants extended to a fifth of its height. Definitely wrong.
MaxwellBuchanan, Feb 13 2017

       //leave trails of pheromones   

       Well, the Soviet astronauts used pencils, so some scaled down version might help?   

       // high altitudes and formidable physical barriers   

       That seems to remind me of something...can't quite put my finger on it...
not_morrison_rm, Feb 13 2017

       // The by product is a bit of condensed water, this should be collected and may be drunk at (slightly disgusting) leisure//   

       I think it is more likely to be ice!
Ling, Feb 13 2017

       Not if you collect it at the point where it condenses out but hasn't frozen yet.
bs0u0155, Feb 13 2017

       A reverse Stillsuit. Totally doable. [link]   

       Actually, the clever thing would be to include sweat in the loop. One of the most irritating tradeoffs with any outdoors gear is how good a protective barrier it is vs how much sweat builds up, we can solve that. When breathing in, the outside air should go through the heat exchanger, into the inner air space of the jacket and then to be inhaled. This passes warm dry air over the body, the body's sweat system will be in a good position to regulate temperature and the inhaled air will be humidified for free. The exhaled air should have the humidity condensed to a liquid, stored to be drunk along the way through something like a Lifestraw to make it less horrid.
bs0u0155, Feb 14 2017

       Sonds like a Dune stillsuit.   

8th of 7, Feb 14 2017

       //Sonds like a Dune stillsuit.//   

       Except mine will work. How is the stillsuit rejecting heat? Sweat allows you to exist in temperatures above body temperature by rejecting excess thermal energy into the fairly robust enthalpy of vaporization. If they condense the sweat in a desert, the energy isn't being lost. If you're in a cold environment, none of that applies. The problem is a huge excess of heat rejection, which gives you much more wiggle room to manipulate the energy flow.
bs0u0155, Feb 14 2017

       Would they look like teletubbies without the tube and antenna ?
popbottle, Feb 15 2017

       See link. Renewable energy, even on a small scale should not be discounted. Solar PV, thermal, wind could all generate a fair amount of power without a lot of extra mass. Even linear alternators could scavenge some energy from the ups and downs of the sled. This energy could be stored in insulated batteries or a phase change material like wax for later use. Of course, a counterflow heat exchanger for breathing sounds like it should already be standard equipment.
TIB, Feb 15 2017

       //wind could all generate a fair amount of power //   

       Plenty of people have done an awful lot of travelling around the polar regions using kites. The consistent and relatively predictable katabatic winds are useful for this and combined with skis can really chew through the miles. This is, of course, cheating. Arctic and antarctic exploration is one of the many Endeavours, where the British example should be the only example. For example, you can ride a modified dirt bike to the pole, you can fly there, you can have sturdy Russians drive a large truck ahead of you setting up cabins. All cheating. Being Norwegian: cheating. Keeping all body parts: cheating.
bs0u0155, Feb 15 2017

       Not dying: cheating...
8th of 7, Feb 15 2017


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