Experimental study on radiant cooling with double-skin infrared-transparent membranes

Radiant cooling is an energy-efficient space cooling technology in built environments to achieve high thermal comfort. However, there are technical bottlenecks of condensation risk and insufficient cooling capacity in hot and humid climates. The use of double-skin infrared-transparent membranes (DIMs) to separate the radiant cooling surface from the air-contact surface can improve the cooling capacity while preventing condensation. Current research focuses on theoretical analysis and reduced scale experiments, and the lack of measured operational and performance data creates a key limitation on DIMs use. Therefore, the verification of radiant cooling system with DIMs in a full-scale experimental space and its radiant cooling performance need to be further studied. In this study, two full-scale radiant cooling chambers (one with DIMs and one without DIMs) were constructed. The effect of DIMs on radiant cooling performance was studied by monitoring surface temperature, condensation risk and cooling capacity. The results indicated that the air-contact surface temperature in radiant cooling with DIMs was always maintained above the dew point temperature for condensation-free safety at a low water supply temperature of 8 °C. In contrast, the conventional radiant cooling without DIMs had severe condensation. Moreover, the cooling capacity of radiant cooling panel with DIMs was 105.5 W/m2 at water supply temperature of 8 °C, 24.4 % improved compared to radiant cooling panel without DIMs at water supply temperature of 14 °C. This study provides prototype experimental verification for new technology with DIMs to improve radiant cooling performance and provides experimental data as a reference for related theoretical and model studies.