Air-con for clothes

Scorched by the desert, or toasted by jets on the scalding deck of an aircraft carrier, the modern soldier must endure conditions so intense that heat exhaustion and collapse is often no more than 20 minutes away.

To this end, researchers at the University of Illinois in Chicago, are using a $4 million DARPA (Defence Advanced Research Projects Agency) grant to develop miniature cooling systems that can be built in to the fabric of a soldier’s clothing.

Scientists in the University’s department of mechanical and industrial engineering are working on the design of a cooling material that will be made from a distributed system of light-weight, ultra-efficient mesoscopic coolers (mesoscopic is a size scale between micron and centimetre).

Using the latest advances in MEMS (Micro Electromechanical Systems) technology, individual coolers will be constructed as thin, flexible membranes measuring about 4 inches on a side and will work along similar principles to conventional air-conditioners. An active vapour-compression system will chill one side of the cooler, rejecting heat on the other side. Each unit will be self-contained, complete with refrigerant, compressor, valves, heat-exchangers, sensors and controls.

According to Mike Phillpott, project manager, a fully functional prototype patch will be demonstrated to sponsors this summer, and the technology will be commercialised in around 2 years.

It’s thought that the system could also be used to cool electronic circuits and infrared sensors, reduce heat signatures from military vehicles, and provide cooling in packaging applications