Studying the effect of “cool” coatings in street urban canyons and its potential as a heat island mitigation technique

Surface temperature measurements carried out during summer period, at canyons’ facades, pavements and street inside a deep urban canyon, in the center of Athens. At the same time experimental data of air temperature were collected through extensive monitoring in the center of the urban canyon. CFD simulations performed in order to calculate surface temperature in buildings’ facades and at street level as well as air temperature inside the canyon. On the first part of this study comparison carried out between the measured and calculated values for a) surface temperature for the initial coating and b) the air temperature in the center of a deep street urban canyon. The calculated data have been thoroughly analyzed and used as well for the CFD model validation. The second task of this work was the calculation of the surface and air temperature, inside the deep urban canyon, by using a “cool” coating and the possible mitigation of the heat island effect in the specific urban area. The use of “cool” coatings, providing high reflectivity of solar radiation on the materials used on pavements and walls inside a canyon, estimated able to decrease surface temperature up to 7–8 °C at ground level. The decrease on walls’ surface temperature estimated close to 2–3 °C. Ambient air temperature inside the urban street canyon may decrease up to 1 °C. The reduction of absorbed solar radiation may lead to the energy consumption and thermal comfort conditions in cities and fight the increased heat island effect.N/