The design and manufacturing of phase change material cooling vests and their effectiveness in reducing thermal strain under laboratory conditions

Water and paraffin are well-known phase change materials used in the manufacturing of cooling vests. The present study was conducted to design and make a cooling vest using commercial paraffin compounds and ice and to then examine their effect on thermal strain parameters in hot climate conditions in a climate chamber. A cooling vest was first made with polyester fabric and containing 17 aluminum packs. Each aluminum pack was filled with 72 g of water and 65 g of prepared paraffin. A total of 10 male students then performed a treadmill exercise in hot climate conditions in a climate chamber (ambient temperature (TA) = 40 0C and relative humidity (RH) = 40%) once with and once without wearing the cooling vest and at two levels of exercise intensity، including a light intensity (2. 8 kph) and a moderate intensity (4. 8 kph) exercise. Each stage of the experiment involved 30 minutes of rest and 30 minutes of exercise on the treadmill. Participants’ heart rate، oral and skin temperature and sweat rate were measured throughout the study. The latent heat of the prepared paraffin was 108 kJ/kg and the peak melting point was 30 °C. Significant differences were observed between participants’ mean heart rate، oral and skin temperature and sweat rate at both exercise intensities and both with and without the cooling vest (P<0. 05). The use of a cooling vest containing paraffin and ice can reduce thermal strain through reducing the heart rate، oral and skin temperature and sweat rate.