Evaluation of Outer Structure Solar Reflection Characteristics of Highly Reflective Material in Consideration of Human Thermal Sensation

As a solution to the influence of solar radiation on thermal comfort in urban streets, constructing outer surfaces with highly reflective materials is considered to be controlling the directional reflection of the materials, and to reflect most of the radiation in the retroreflective direction-the same direction as that of the incident radiation. This study experimentally and numerically evaluates the directional solar reflectance of the outer cover material having an uneven surface. There is found to be a strong impact of radiation on human thermal comfort, and reduction of this radiation is the key to improving the thermal environment. Accordingly, the use of highly reflective materials is a good strategy for enabling this improvement, and retro reflection is a promising concept to consider in this regard. The simulation results show that human thermal comfort is determined by retro reflection if solar reflectance is the same.