Cool Roofs in Hot Climates: A Conceptual Review of Modelling Methods and Limitations

Abstract

Cool roofs are a long-term alternative for the creation of a building’s thermal comfort as they can reduce the energy required for cooling demands and mitigate the urban heat island effect, thus benefitting both buildings and cities. Interest in cool roofing has recently escalated and numerous concepts, techniques, and experiences are represented in various studies conducted for hot climates; however, in reviewing the literature, it was found that most of this research is limited to the investigation of these benefits at either the building or city scale. Indeed, only six attempts were found that integrated both scales. To assist with design decisions, several studies have concluded there is an urgent need for a multi-level, interdisciplinary assessment framework, but as yet no such framework has been constructed. Following the literature review, in this study, a general framework is proposed which permits current modelling to progress beyond typical protocols, by including data linking a specific urban microclimate at the neighbourhood/city level with that of a building, thus connecting the microclimatic environment with objective assessment of energy efficiency. It is hoped that this framework will promote the development of exclusive cool roof applications for buildings and outdoor urban settings.

Keywords

• cool roof
• energy efficiency
• hot climates
• thermal performance
• UHI mitigation