Design of Thermal Manikin for Experiment of Cooling Vest

Abstract

The focus of the present work is to design a physiologically efficient cooling garment for army-personnel that will help to maintain their body core temperature within comfort limit when they are exposed to adverse climatic conditions for extended duration of time and ultimately prevent heat related injuries. Emphasis is placed on design optimization of physical functionality of the vest for cooling/heating efficiency, comfort level, comfort duration and safety. Thermal design of vest components consisting of the phase change material (PCM), external fabric material, and skin-contact material is under consideration. The material properties of each component and their role in thermal design are critical in the process as the protective vest must operate in adverse climatic conditions with extreme hot and cold ambience with possibilities of very high relative humidity. Several aspects like orientations, dimensions, and thermodynamic properties of the different phase change materials (PCM) pack are to be considered to obtain optimized vest design. The design of a human replica under extreme thermal stress is considered. The skin temperature evolution under the influence of water gel PCM pack is studied when the ambient temperature is maintained at 48?. The body heat generation is replicated by resistance heating. Experiments are performed in an environmental chamber, where extreme atmospheric conditions like humidity, temperature and wind flow can be reproduced artificially. Different ranges of body heat flux are considered by designing controllable resistance circuit. Duration of thermal comfort is studied under varied body heat generation condition, and varied insulation thickness between PCM pack and the heated plate replicating the skin.