Cool suits.
Used by suit guys or the actors in heavy full body suits in film. I worked on the older stuff about ten years ago in LA. Those who wear the heavy full body suits need to be kept cool under the lights or they pass out.
They are also used by some race car drivers, I believe. They circulate propylene(sp) glycol through the suit, which consists of a vest like garment heat die pressed with many continuous channels that the glycol runs through. The hitch will be that a small pump and chiller is needed to transpire the heat out of the warmed glycol once it comes back from the wearer.
These are big enough to make it unusable for the foot soldier, today, but not impractical for anyone to plug into it in a himvee or tank or troop carrier that can have the system built into the vehicle.
They are probably already working on it I am sure.
Kentlik TPD