It seems like the Japanese always have the coolest technology--in this case quite literally. The hip new way to stay cool in an increasingly energy-conscious Japan: cooling foam or gel spray-cans that go right on the skin and provide an instant cool down.
These cooling sprays apparently aren't brand new, but a thing isn't a "thing" until it goes mainstream in Japan, and this summer that's what's happening. City-dwellers are using the products to cool down on the subways or on the streets. Particularly cool: the foam-like spray that hardens quickly out of the can, so users can make cooling wristbands or neckbands to help keep their core temps under control.
Check out the whole arsenal of cool cooling products at Japan Trends.
Or you could just put your hands under cold tap water for 1/50 the cost. Use some ice cubes from the freezer for extra comfort.
Perhaps theres a military application, no running water when I was deployed.
ummmmm idk maybe
So can anyone figure out how these work? I cant seem to figure out what this stuff is made out of. For all I know it just causes nerve damage that make you think you feel cool. It probably doesn't but unless there is an explanation that this article doesn't provide I can only make wild assumptions.
Euroson - I think it's designed for sitting in parks where perhaps running water isn't conveniently available. No one's saying you'll need it to survive
Corwinb - presumably it's just an endothermic reaction with the air?
I'm not sure about the foam, but i would wager the gel is nothing more then something the evaporates quickly, and has a fairly high specific heat. Kinda like the way an alcohol base cologn feels cold when applied to the skin.
What about all the energy required to make the millions of spray cans and all the packaging, and the energy required to dispose of them all in landfills? Doesn't seem so energy efficient to me...
I agree with lesses; the energy efficiency claim is quite suspect...
However, I do see these as being useful for military, first aid, etc. applications. So, overall I think they are probably a worthwhile device.
Have any of you guys ever shot a CO2-powered gun? Like a paintball gun?
The faster you discharge the CO2 canister the colder it becomes. I wonder if maybe the same principle is in effect here.
@B.V. With any fluid, lowering its pressure decreases its temperature, because the present heat is spread over a larger area. The blue foam comes out of the can cold because it goes from high to low pressure. CO2 canisters get cold when you discharge them quickly because the interiors depressurize.
As for the fizzly stuff, it seems to be a compound that's supposed to be a gas at some temperature (perhaps the mentioned -9 degrees C). Liquid in the can, it simply absorbs a bunch of heat from the skin as it boils and evaporates.
As far as air pressure goes, the opposite is true as well - compress a gas, and its temperature increases. One can prove this with a stopper in a tube (perhaps a test tube or graduated cylinder) that has a small combustible fiber in it, such as cotton. Ram the stopper down the tube and the fiber instantly combusts - at least, if the pressure gets high enough.
All that said, these are quite clever things! As someone who was only saved from death by heatstroke by the presence of a nearby car with an A/C (and the timely activation of pop-up sprinklers), I can say that having one of these around could have been really useful. If you're going to take a jog or work out despite the heat, stick some of the gel on your neck; if you're just too hot and need to cool down when there's no cold water around, the second one shown will do the job nicely.
Great! More goop to throw in Tokyo Bay.