The effect of building surface cool and super cool materials on microclimate in typical residential neighborhoods in Nanjing

The application of cool materials in cities inevitably has an impact on the urban microclimate, but there is a lack of such studies. Therefore, this study investigated the effects of cool and super cool materials on building surface temperature, pedestrian-level pollutants, and neighborhood ventilation capacity using the CFD simulation method based on six typical residential neighborhoods in Nanjing, China. The results show that the cooling effect of the cool and super cool material on the building surface of slab morphology is greater than that of the building surface of point morphology at noon due to the buildings of slab morphology having a larger area of the south façade to reflect more solar radiation. The highest reduction in roof temperature is 10.7 °C and 13.4 °C for cool and super cool materials in summer. In addition, residential neighborhood with slab-parallel arrangement has the highest pedestrian-level pollutant concentrations regardless of building surface material. The effect of cool and super cool materials on the residential neighborhood's microclimate is small, less than 6% in summer and winter. In short, cool materials have a greater impact on the heat gain of buildings and can contribute to building energy efficiency in summer.