ARTICLE Mun_ENB_2026/IDIAP Effects of cool coatings on urban microclimate and outdoor thermal Comfort: A CFD?CitySim pro coupled simulation study Mun, Da-Som Kämpf, Jérôme Kim, Jae-Jin CFD model CitySim Pro Cool coating materials Pedestrian thermal comfort Urban heat environment Energy and Buildings 2026 https://www.sciencedirect.com/science/article/pii/S0378778826003051 URL https://doi.org/10.1016/j.enbuild.2026.117245 doi This study examines how cool coatings, which modify the radiative properties of building and ground surfaces, affect urban microclimate and pedestrian thermal comfort in a district with heterogeneous building heights. A computational fluid dynamics (CFD) model coupled with CitySim Pro explicitly resolved shortwave and longwave radiative exchanges. The framework was validated against field measurements, demonstrating high accuracy for surface/air temperatures and wind speed/direction in the control experiment (CNTL) using in-situ material properties. Sensitivity experiments revealed that high-rise facade coatings (BiGc, BiGj) reduced the coated facade surface temperature by 4.70–5.56℃, but increased temperatures on nearby low-rise facades and roofs by up to 6.03℃ and 4.06℃, respectively. In the combined case (BiGj), adding high-reflectance pavement mitigated the facade-induced ground warming observed in BiGc by ∼ 2℃. Ground-only coatings (BcGj) lowered pavement temperature by 1.71–2.24℃ while producing only minor thermal changes on surrounding buildings. Regarding air temperature, ground-only coatings produced marginal nighttime cooling and ∼ 0.5℃ daytime cooling, primarily over open spaces. Facade-involved scenarios achieved up to 2℃ daytime cooling near deep canyons but caused localized nocturnal warming of 0.3–2.0℃ in medium and shallow canyons. Universal Thermal Climate Index (UTCI) analysis at the Gwanghwamun Square showed ground-only coatings increased daytime UTCI by < 1℃ on average, whereas facade-involved treatments raised UTCI by up to 4.13℃ due to intensified mean radiant temperature. Overall, ground-centric coatings minimize comfort penalties, while facade treatments require strict radiative control. Prioritizing shaded ground applications in high-activity areas offers a practical balance between urban cooling and pedestrian well-being.