An evidence-based framework for designing urban green infrastructure morphology to reduce urban building energy use in a hot-humid climate

Urban green infrastructures (UGIs) play an essential role in reducing urban building energy consumption by cooling surrounding areas and shielding buildings from direct solar radiation heat gain. Although the energy-saving effect of UGIs is widely agreed upon, there is a lack of systematic knowledge about how UGI morphology affects urban building energy consumption. Consequently, an effective method to design UGI morphology to reduce urban building energy consumption in urban design is not available. A grading system was proposed to evaluate the strength of evidence for the findings and conclusions in studies that pertain to the cooling and energy-saving effects of UGI. The evidence-based literature review found that strategically designing the morphology of UGI, including its size, shape, location, connectivity, spatial pattern, and configuration, can effectively reduce the air temperature surrounding the UGI area and building energy demand. This study formulated a morphological design framework for UGI as part of the urban design process to reduce urban building energy consumption. Based on the evidence-based answers to the key questions in the framework, design strategies are provided as visual charts and technical principles. The study includes an urban design case in Nanjing, China, which applied this framework to achieve the goal of urban energy savings.