Chemical and biological warfare suits worn in warm climates, such as the Iraqi desert, can become unbearably hot. The solution may be a portable cooling system that weighs just several pounds.
The concept that makes this possible also is leading to miniature sensors for detecting chemical and biological toxins, as well as tiny chemical reactors for hydrogen fuel processing or environmental cleanup.
In a nutshell, small is powerful. These devices send large amounts of liquid or gas through thousands of microchannels that stand roughly as tall as a human hair. In each channel, heat transfer or chemical reactions happen more efficiently than they do in larger spaces, permitting better process control, shorter channel lengths and overall system miniaturization.
"The channels are to microfluidic devices what wires are to microelectronics," said panelist Brian Paul of Oregon State University.
While conventional refrigeration systems in the United States require huge amounts of electricity, the one designed by Ward TeGrotenhuis and his colleagues at Pacific Northwest National Laboratory could run off burning fuel, carried in lightweight, portable canisters. They have demonstrated that miniaturizing each of the components of such as system is possible and are now working on fitting all the pieces together.
The final product would consist of an absorption heat pump, which would fit in a small backpack, connected to a vest threaded with water-filled microchannels. The water would be cooled in the pump then recirculated through the channels to keep the person wearing the vest from o
Contact: Monica Amarelo
American Association for the Advancement of Science