Development of a Retro-Reflective eco-friendly clay rooftile to mitigate the Urban Heat Island (UHI) effect

Abstract

The Urban Heat Island (UHI) effect, where the urban areas experience higher and warmer temperatures compared to surrounding rural areas is currently becoming a serious climatic phenomenon common to a lot of large cities around the world. This rise in urban temperatures lead to an increase in energy consumption of buildings and moreover, thermal discomfort to people and affects the quality of human life. There have been reported cases that this high temperature has adversely affected infants, elderly people and people with poor health conditions. Several strategies have been proposed and developed to overcome the UHI effect. This study is focused on developing a rooftile as a mitigation strategy for UHI. Sieve analysis was done and 1.18mm to 0.6mm waste glass particle size was selected as the optimum particle size for designing the reflective layer. Then rooftile was designed by applying the reflective layer, RR glass bead layer and protective sheet and Retro-reflectivity testing was done to check the RR properties of developed Rooftiles. The temperature around Wayamba Royal College, Kurunegala, Sri Lanka has been analyzed in the current study. It is located in a highly crowded area with high relative humidity and temperature. Field temperature data was collected from 15th of April to 19th of April using a pre-prepared electronic setup. The developed rooftile has reduced the surface temperature by 11.81 °C in the peak temperature hour of 11a.m to 12 noon on 19th of April. Therefore, this study explains the concept of UHI and the efficiency of RR rooftiles in mitigating the UHI effect.