Investigation of the Solar and Thermal Properties of Materials Used in Outdoor Urban Spaces and Buildings

This paper aims to report the solar and thermal data for various common and innovative materialsused in outdoor urban applications. The tested materials include various types of coatings, tiles andasphalt pavement. In the framework of this research, the spectral reflectance and the emissivity of thematerials were measured using a UV/VIS/NIR spectrophotometer fitted with an integrating sphere andan emissometer. The solar reflectance of the samples was calculated. Furthermore, the influence ofthe solar reflectance and the infrared emittance on the surface temperature of the materials wasanalyzed by calculating the surface temperature that each material can reach when exposed to solarradiation. Experimental data on the surface temperature of the tested materials, acquired by usingsurface temperature sensors and a data logging system, are also reported. Materials with high albedoand emittance, the so-called cool materials, attain lower surface temperatures when exposed to solarradiation, reducing the transference of heat to the environmental air. High surface temperaturesincrease the demand of energy, they accelerate the formation of harmful smog and cause humanthermal discomfort by intensifying the heat island effect in urban areas. The results of this study willassist in a good environmental planning, with the selection of more appropriate materials for buildingsand the urban environment, contributing to the mitigation of the heat island effect.