Cooling energy performance and thermal characteristics of a naturally ventilated slim double-skin window

•The cooling energy performance of the SDSW was experimentally evaluated.•Based on the measurements, CFD modeling of SDSW was carried out.•The effect of outer single glazing on SDSW was analyzed.•The temperature distribution, heat transfer mechanism, and thermal performance of the SDSW were identified. A slim double-skin window (SDSW), which is a window that is naturally ventilated through a thin cavity of 20 mm, has recently been developed. This study aims to analyze the cooling energy performance of SDSW through field measurement and to numerically investigate its thermal characteristics and the influence of outer single glazing on it. The results of the field measurement showed that the room in which SDSW was installed had 9% less total cooling energy for a week in summer as compared to the room in which the triple glazing window was installed. The simulation results indicated that by changing the type of outer single glazing, the total solar heat gain (TSHG) differed by up to 34%. In addition, when the outer single glazing was low-emissivity glass, SDSW was the most effective. In the heat-transfer mode of the TSHG, the type of outer single glazing significantly affected short- and long-wavelength radiation rather than convection.