Design and evaluation of a micro-climate cooling system using a vest with ice bags

A microclimate cooling system was designed in this dissertation project. The system consists of a vest with 54 small ice bags inserted in the pockets sewn to the Inside of it. The system was tailored in such a way as to open and close in front (to be worn as a vest) and on both sides (to be worn as a poncho).

The effectiveness of the designed cooling system with (DCSS) and without (DCSN) a slicker worn over it, and a South African cooling system (SACS) in reducing heat stress encountered by men working in hot environments was evaluated. Testing was conducted in an environmental control chamber to simulate hot-humid and warm-humid environmental conditions. Two workloads, moderate and heavy, were performed by the four subjects who participated in this project.

Under the hot thermal condition the average tolerated exposure time by the subjects when not using a cooling system was 72.5 minutes when they performed the heavy workload, and 85 minutes when performing the moderate workload. But, when the cooling systems were utilized, all subjects completed the 95-minute work sessions. Under the warm condition the subjects were able to complete all work sessions even without a cooling system.

The effectiveness of the cooling systems in reducing physiological strains and subjective responses (i.e., the feeling of discomfort and thermal sensation), especially under the hot condition, was statistically significant.

It was concluded that both the cooling system designed for this study and the South African cooling system were effective in reducing the heat stress associated with working in the hot-humid condition investigated in this study. It was also concluded that the performance of the designed cooling system was better than that of the South African cooling system and the best results were achieved when a slicker was worn over the designed cooling system.