Review on integrated photovoltaic-green roof solutions on urban and energy-efficient buildings in hot climate

Abstract

• A review was made for 157 and 28 papers of GR and PV/GR systems, respectively. • The potential research gaps of GR and PV/GR were specified in different climates. • The GR key factors are LAI, soil depth, insulation, irrigation and coverage ratio. • GR type, irrigation and plant features are the common factors for GR and PV/GR. • The vegetation, urban and irrigation factors aren't studied enough in hot climate. Climate change and urban heat islands (UHIs) pose mounting threats to built-up areas. In this regard, photovoltaic panels and green roof systems (PV/GR) can offer numerous benefits towards promoting environmentally sustainable cities. This review examines the benefits of GR systems, integrated PV/GR systems and their optimal design factors; research gaps in urban scales and building scales in hot climates are highlighted. A systematic review was undertaken on published papers from the Scopus database that investigated the effect of GR (157 papers) and PV/GR systems (28 papers) that addressed UHI mitigation and how Energy-Saving and Indoor Thermal Comfort (UH-ES-ITC) was achieved in urban buildings. It has been found that GR and GR/PV systems have a positive impact on improving dominant parameters in hot arid climates, especially on the building scale. Unfortunately, there are not many studies that investigate GR/PV systems on coupling scales. This review highlights the research gaps concerning the method, scale, climate, target, factors and parameters of this integration in different climate zones. The results would be valuable for researchers and urban planners to guide research implementation and future research.