Cooling Effectiveness of a Hybrid Microclimate Garment

A prototype microclimate cooling garment that would allow the wearer to connect to either an air or a liquid cooling unit was tested and compared with existing air and liquid vests. Five male soldiers wore the three garments (hybrid, air, and liquid) on different days while walking on a treadmill in a climatically controlled environment. The chamber conditions were: dry bulb temperature, 38c (100F); relative humidity, 20%. The exercise generated a 332-W metabolic rate. The average metabolic rate (including rest periods) was 287 W. The hybrid garment, in either mode, performed as well as the individual air and liquid garments. Though the hybrid vest succeeded physiologically, comfort and fit problems were revealed that will require major changes in the next iteration.