Experimental study on condensation-free radiant cooling panel with low-temperature for local cooling in vehicles - Part 1: Design process and feasibility evaluation with performance test

Although radiant cooling has significant advantages (high efficiency and thermal comfort), insufficient cooling capacity and condensation risk limit the practical application. In this study, a novel condensation-free radiant cooling panel (RCP) with high cooling capacity is proposed. The performance of proposed RCP was experimentally evaluated at different operating conditions. The transparent cover and surface-painting spray materials of the RCP were examined using Fourier-transform infrared spectroscopy to analyze their transmittance and absorptivity. The total cooling heat flux of the proposed RCP ranged between 2019.5 and 3824.5 W m^–2, which are significantly higher than those of previous studies (70–1457 W m^–2), owing to low surface temperatures. The radiant heat flux decreased by 13.5% when the distance between the cooling surface and the heater increased from 10 cm to 20 cm, and decreased by 52% when evaporating temperature increased from –40 °C to –20 °C. However, the heater and ambient temperatures showed insignificant effect. The results of this study report feasibility of the proposed RCP and parameters that influence performance. The target application of the proposed RCP is local cooling systems in vehicles to enhance thermal comfort, which is given in succeeding research, Part 2: Demonstration with passengers for thermal comfort analysis.