A simulation study on the indoor thermal environment of an office building with transparent radiative cooling (T‐RC) film in Nanjing, China

• The impact of T-RC film on indoor thermal environment is studied by CFD simulation. • The window-to-wall ratio (WWR) and orientation of the windows are considered. • The best cooling effect of the T-RC film is observed in the south room (1.91 °C). • The cooling effect of the T-RC film is ineffective when the WWR is 30 %. • The effect of window orientation on the cooling effect is not negligible. The application of radiative cooling materials in buildings can effectively improve the indoor thermal environment in summer. This study used computational fluid dynamics (CFD) simulation to investigate the impact of transparent radiative cooling (T-RC) film on the indoor thermal environment of an office building in Nanjing, Jiangsu Province, China. The window-to-wall ratios (WWR) and orientations of the windows were also considered. The simulation results indicate that the best cooling effect of the T-RC film on indoor average air temperature is observed in the south room (1.91 °C), followed by the east room (1.59 °C) and then the west room (1.5 °C), while the cooling effect in the north room is limited (0.56 °C). The cooling effect of the T-RC film is best in the west room at WWR 50 %, while in the east and south rooms at WWR 75 %. The cooling effect of applying the T-RC film only to the south-facing windows is 61.4 % and 57.9 % of applying film to all windows for the west and east rooms, respectively. This study can provide a reference for the effects of applying the T-RC film to office buildings, inform the design or retrofit scheme of building windows, and provide helpful information for making a more comfortable indoor thermal environment.