Personal-portable Cooling Garment Based on Adsorption Vacuum Membrane Evaporative Cooling

Abstract

A cutting edge man-portable AVMEC cooling garment was demonstrated to be able to provide sufficient cooling for personnel working at mediate activity loads. Studies were first carried out in a well controlled vacuum desiccator at room temperature to elucidate the effects of several key parameters on the performance of an AVEC device, which was similar to AVMEC except that membrane was not involved. Under the best condition, an average cooling capacity of 179 W/M2 was achieved in a period of four hours and cooling continued at a slowly declining rate for another four hours afterward. The temperature of water was maintained at approximately 12.5 oC after the pseudo steady state was established. Then, it was shown that the AVMEC cooling pads were able to provide a cooling capacity of 277.4 W/m2 in a 37 oC ambient environment (incubator). The temperature of the cooling core surface was maintained in a range of 20 – 21.8 oC in the one-hour test period. No power supply was required except for the initialization stage, which took 5 minutes. Furthermore, human subject tests with or without wearing NWBC (Nuclear Warfare Biological and Chemical) suit demonstrated that, a AVMEC garment composed of 12 cooling pads were able to maintain the core body temperature of the subjects below 38.5 oC for up to 90 minutes while the subject was walking on a treadmill at a speed of 2 miles per hour in an environment of 40 oC and 50% RH (relative humidity). These results indicate that the AVMEC garment is a promising man-portable personal cooling technology.