Experimental study on condensation-free radiant cooling panel with low-temperature for local cooling in vehicles - Part 2: Demonstration with passengers for thermal comfort analysis

Radiant cooling is highly energy efficient and provides excellent thermal comfort; however, owing to the large area required, it has primarily been applied to indoor space cooling. In this study, a low-temperature condensation-free radiant cooling panel (RCP), proposed in a related paper (Part 1: Design process and feasibility evaluation with performance test), was applied to an actual vehicle to study its effect and impact on thermal comfort. Thermal satisfaction and sensation were assessed using a subjective survey, and skin temperature was investigated using objective measurements in 17 participants. The results showed that the proposed RCP provided the passengers with better thermal comfort under solar radiation; furthermore, 95 % of participants found it more satisfying when the RCP was turned on, and the overall thermal sensation vote tended to be neutral (0) from warm (2) after operating the RCP for 5 min. In addition, thermal sensation in the head and upper body had a major effect on the overall thermal sensation, whereas thermal sensation in the lower body was of no importance to the overall thermal sensation. The RCP used in this study can maximize the energy-saving effect through local cooling, particularly in vehicles with large spaces.