Jihui Yuan
Huazhong University of Science and Technology, China
Title: Development of glass bead retro-reflective envelope to mitigate the urban heat island and reduce building energy consumption
Biography
Biography: Jihui Yuan
Abstract
Heat from buildings accounts for approximately half of urban anthropogenic heat contributing to the urban heat island (UHI). The proportion of heat from building envelopes accounts for approximately 1/3 of the anthropogenic waste heat total in Japan. Highly reflective (HR) and retro-reflective (RR) envelopes are being studied as one solution. RR materials are being applied to building facades instead of HR materials for UHI mitigation. Glass beads are the common main component of RR material. In order to evaluate the influence of glass bead RR materials on UHI mitigation, several types of glass bead RR samples with different refractive indices and different color reflective layers were developed for this study. Their RR angular distributions of reflection intensity were investigated by an emitting-receiving optical fiber system. It showed that the RR characteristic of a glass bead RR sample with a refractive index of 1.9 is more effective than that with a refractive index of 1.5. Additionally, for possible application to building facades, the long-term durability of these samples was also investigated by an outdoor exposure experiment for about 9 months. It showed that both the solar reflectivity and RR characteristics of these RR samples have no significant decrease over that time in the outdoor environment.