Analytical model to evaluate the reflective directional characteristics of retro-reflective materials

Abstract

In order to mitigate the urban heat islands (UHI) phenomenon, instead of diffuse reflective (DR) building coating material, retro-reflective (RR) coating material is proposed to be applied to external wall surface of buildings. The reflective directional characteristics of RR materials can be usually investigated through optical measurement. In addition to the method of optical experiment, there are other methods of analytical models predication. This study deals with an optical experiment and two analytical models to evaluate the angular distribution of reflection intensity for RR materials. A total of three RR materials, including prism type plate, capsule type plate and glass bead type plate are created, and their angular distribution of reflection intensity were evaluated by using methods of optical experiment and two analytical models (original analytical model; anisotropic body of rotation of the normal distribution function (AND) model). In order to propose an appropriate analytical model of evaluating the reflective directional characteristics of RR materials, regarding the angular reflection intensity obtained by optical experiment as a real value, the results evaluated by two analytical models are compared in this study. It is shown that it is better to apply the AND model to evaluate the reflective directional characteristics of RR materials, compared to original analytical model.