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Anti-Frostidigitation: Heatpipe Gloves
Hettinga writes "A little casemod couture this morning, courtesy of Hongbin Ma, a professor of Mechanical and Aerospace Engineering at the University of Missouri. He has developed heatpipe-driven gloves which pump therms from your toasty upper arm down to those aforementioned frosty digits. 'Each glove contains five small heat pipes, one for each finger, that are about 14 inches long and 1 mm x 2 mm in the cross section. Each pipe consists of three sections: an evaporating section, which is attached to the upper arm area; an adiabatic section, which is between the finger area and the arm area; and the condensing section, which is attached to the finger area.' Coming soon to a half-pipe near you..."
Here is how a heat pipe works
A. Heat is absorbed in the evaporating section.
B. Fluid boils to vapor phase.
C. Heat is released from the upper part of cylinder to the environment; vapor condenses to liquid phase.
D. Liquid returns by gravity to the lower part of cylinder (evaporating section).
If you wore these long enough in cold weather (-20C or less) would you risk decreasing your core temperature to critical levels?
Ride recklessly only when safe to do so.
Sounds neat and all, but they've already shown that maintaining a certain temp in your torso area will help keep those extremities warm. I'd think it would use heatpads on your chest.
Damon,
http://actionPlant.com
He has developed heatpipe-driven gloves which pump therms from your toasty upper arm down to those aforementioned frosty digits.
If he has 'developed' these gloves, I would like to see a picture of them. It looks like these are just as 'developed' as those night-vision contacts over at Popular Science.
Yeah, I do some survival stuff. My rule that I tell anyone who will listen, regardless of whether they are in a survival situation, is : Always keep your torso warm!
Doing this helps prevent shivering, which saps EVEN MORE energy from you. It also helps protect from hypothermia by insulating the core, and not the extremities. Having your core temperature drop is WAY worse than having cold hands!
That reason is: It is better to lose a finger than a lung.
Don't be stupid... keep your body warm first.
42 - So long and thanks for all the fish.
Nope. Heatpipes use a fluid and working pressure such that the fluid is almost-boiling at the optimum operating temperature. Heat one end, and the fluid boils, vapor diffuses rapidly to the other end, condenses giving up heat of vaporization, and is absorbed into the wick that runs through the pipe. It then goes back to the other end by capillary action.
That said, it IS more efficient if the bottom end is the "hot" end, 'cause the rising warm fluid vapor and the down-flowing condensed fluid are both assisted by gravity. However, gravity is NOT an essential part of the process (some satellite instruments use heatpipes to keep-em cool in free-fall, for example).
A friend of mine does heat pipes as a business: koolpipes.com
"My strength is as the strength of ten men, for I am wired to the eyeballs on espresso."
While Missouri may be 'south' in a general sense they do get cold weather. Enough to warrant the usual coats, hats and gloves thing that those who live further north (Chicago, Boston, Bangor, etc) use every winter.
In fact, the majority of Tennessee is further south than the entire state of Missouri is and they regularly get snow storms and cold weather.
Your attitude reminds me of a roommate I had in college who was from New Hampshire. No matter how cold it was in RI (where I finished school) or my home state (a bit further south) it was always 'warm' to him because New Hampshire winters were colder.
Just because 20 above is warmer than 20 below doesn't make it warm.
The reason your hands get cold and numb isn't because they are actually so cold (umm sort of; bear with me); its because your core temperature drops and your thermal maintenance systems shut down blood flow to the extremities. Loss of blood flow in the hands results in the numbness and loss of dexterity.
:)
If you wear a heated vest (or even just keep a charcoal-burning hand warmer in a chest pocket (nice and low tech)) your hands don't get all cold and numb; they stay dexterous and warm. And without *any* gloves at all.
Ok so *serious* below zero temperatures will still result in skin loss if you *touch* something...
In the free world the media isn't government run; the government is media run.
Wrong! I spend my whole winter biking in -20 (Saskatoon, Canada). My biggest problems are keeping my extremities warm. I usually wear big double mitts, but leave my jacket open to exhaust the heat and moisture from my body. I would love to transfer that excess heat to my hands and feet! Things would be different if I wasn't generating so much heat...
Only if the other garments you were wearing were inadequate for the task of maintaining your body temp despite the extra heat loss to your hands.
:)
But if you're wearing these gloves, but aren't otherwise wearing clothes appropriate to -20, then yeah, you might get hypothermia.
On the other hand, hyperthermia is unlikely to be a problem caused by these gloves in -20C weather.
The enemies of Democracy are
There is a reason that the body restricts blood to the extremities in extreme cold. It's probably better to get a bit of frostbite than hypothermia. Frostbite may cost you a few fingers, but hypothermia makes you confused and uncoordinated, until eventually you lay down in the snow to sleep (and die).
These gloves may be thinner lighter and warmer than gortex gloves, but goretex you can take off when you have to do delicate work (starting a fire) and you can put your hands in your armpits if they get too cold. These gloves require you to take off your coat and shirt and any fleecy layers you may be wearing when it is time to put them back on.
You can have these gloves. I'll keep wiping my nose with my wool mittens.
More music, fewer hits
RTFA.
Ma, who also is developing the same device for shoes, is the founder of MU's Research Consortium for Innovative Thermal Management
A lot of readers seem to be missing the point here. The real advantage of this prototype is that it's passive - no batteries, no chemical reactions, nothing. It keeps your fingers warmer by absorbing some heat from your body (that would eventually have ended up in the air) and transferring the heat to your fingertips.
So yes, hand warmers are cheap and effective, but they'll die after a few hours once the reaction finishes.
Keeping your core temp high is a nice idea, but let's say you already have a nice coat and things - I think having some gloves that would passively heat my fingers would be nicely appreciated. Their was a post about how if it's a matter of life-or-death, you should maintain your core temp, but I think the more realistic application of these gloves would be to maintain comfort of your digits when you know you're going to be outside.
Again, the system is passive - no batteries, no chemical reactions, nothing at all. You'd put them on and forget about it.
I live in Edmonton, Canada. As such, I have to regard phrases like "even below zero (celsius)" with some amusement. Keeping your core warm certainly does help the extremities, but is not a full solution. Walking to school, I remember many times when my hands/ears/feet were freezing while I was sweating inside a huge coat.
I think this likely varies in different people, temperature, wind, activity, etc.. There's lots of situations where I would have been happy to move heat from arm to hand, and when my core was perfectly toasty.
Let's not stir that bag of worms...
No, negative temperatures on the Kelvin scale are possible, sort of. See this page or this page for example.
It's official. Most of you are morons.
Not quite. Even considering a generous definition of "human history" spanning 1 million years, if matches weren't available for 99.99999% of "human history" then they weren't invented till a little more than a month ago. :-)
You probably mean "99.9823%" instead, as chemical friction matches were invented in 1827. Decimal points are powerful things. :-D
Mittens stop your hands losing heat. The heatpipe gloves take heat away from one part of the body and move it to another (less essential) part, and probably increase the total heat loss a bit.
The heatpipe gloves would reduce your core body temperature. Mittens would not.
-- Ed Avis ed@membled.com
I think you have missed the point, they would indeed remove the ambient heat, which would lower the surounding temp of the arm, which would again lead to more heatloss, so the grandparent was indeed correct.