Efficacy of a water-cooled garment for auxiliary body cooling in heat

Abstract

The efficacy of a water-cooled jacket for auxiliary body cooling was examined under a simulated hot environment. The personal garment comprised of a water re-circulating three-layered vest of cotton fabric lined with 2 mm diameter latex tubing and inter-spaced coating of rubberized solution. Four subjects wearing the water-cooled jacket were tested in the environment chamber (30, 35 and 40°C DB, 50–60% RH, air velocity 0·3, 0·6 and 0·9 m/s, with corresponding average effective temperature of 26±2·3, 33±1·1 and 36±1·5 C). The inlet water temperature was maintained at 10–12°C, with flow rates of 2·6±0·3, 4·3±0·3 and 5·1±0·3 l/h). At 30°C DB, variation in water flow had marginal effect on microclimate, while at higher temperatures (35 and 40°C DB), the re-circulating cooled water had noticeable effects in lowering microclimate, trunk and other skin temperatures, and maintaining the body core within 36·7±0·2 to 37·5±0·2°C, over 2 h exposure at 35 and 40°C DB. The observation indicates that the watercooled jacket provided auxiliary cooling to maintain comfortable microclimate, skin and body core temperatures. This enabled subjects to sustain comfortable heat balance over 2 h heat exposure without any noticeable heat strain.