This range of undergarments contain quilted pockets filled with a phase change substance with a transition point just around 40C. (above normal body temperature of 37C). Worn underneath the usual assortment of winter clothes, it absorbs heat generated by vigorous human activity, thus reducing over-heating. When the vigorous activity ceases and the cold outside temperature begins to make its presence felt, the pockets undergo phase change back to solid form and release heat back to the body.
Obvious markets would be for winter athletes such as those engaged in sports such as the Biathlon, Cross Country Skiing or Gridiron Football. Tree loggers, hunters and ice fisherman who have to hike to their destinations then have periods of inactivity In the cold could also benefit. Unlike other pocket heaters these are reusable and require no external fuel source.-- AusCan531, Dec 15 2013 Phase-change underwear http://spinoff.nasa...inoff2012/cg_3.htmlBaked. [spidermother, Dec 15 2013] Good for winter cycling in the snow and ice - sweat going up hills, shiver going down.-- pocmloc, Dec 15 2013 (+) for the concept... and another (+) for the link.-- 2 fries shy of a happy meal, Dec 15 2013 //More than two decades ago//.
That means I'm two decades behind NASA :(
On the positive side, that makes me about two decades ahead of China.
Great link [spidermother]-- AusCan531, Dec 15 2013 And in the summer when it gets to hot they simply evaporate.-- pashute, Dec 18 2013 random, halfbakery