Assessment of thermal comfort performance of membrane-assisted radiant cooling outdoors

Membrane-assisted radiant cooling panels provide the possibility of active cooling in outdoor environments by reducing convective heat transfer between the radiant surface and open air and mitigating the risk of condensation. A membrane-assisted radiant cooling panel system was constructed in an open space to perform thermal comfort investigations. There were 248 subjects participating in the thermal comfort investigation under three different panel surface temperatures. During the experiment, the subjects were asked about their feelings about thermal sensation. It was indicated that the thermal sensation vote (TSV) improvement percentage is higher in the transitional season compared to the hot season. The thermal comfort created by the cooling of the back trunk offsets the thermal discomfort on the front side of the body (e.g., face, head, chest, etc.) and, therefore, lowers the overall TSV even if the subject stands under the cooling spot with some degree of radiant asymmetry. This study would be helpful for future research on improving thermal comfort in outdoor environments.