China's urbanisation has entered its mid-to-late stages, deciding a necessary transition into a phase of renewal and redevelopment. Climate emergencies are another main theme of global cities prominently shaping a sustainable, climate-resilient design paradigm. Accordingly, there are significant needs and potential of urban renewal among old neighbourhoods and precincts, in order to enhance their vitality, resilience and liveability. However, due to long, extensive construction processes and the absence of systematic, sustainable planning and design practices, existing knowledge of climate resilience can hardly transform into successful practical actions.
To overcome these challenges, this study aims to explore science-based solutions of urban renewal of an old riverside residential neighborhood built in 1980s in Bishan, China. In alignment with an old version of building codes and requirements, this neighbourhood lacks sustainable environmental design and resilient climate solutions. It has a weak connection with its surrounding river landscapes and always exhibits hot stuffy environments during the long-lasting extreme heat season. As a result, this neighbourhood is among piloting renewal projects of the Global Environmental Facility to explore feasible pathways and demonstrate performance to assembled neighbourhoods globally.
Based on 3D microclimate simulation software (ENVImet Version 4.3), this study explored five implementable pathways with different cooling mechanisms, such as building forms and spatial layouts, roof greening, building envelope materials, façade coating materials, and ground pavement materials. A total of 50 simulation scenarios were carried out under extreme heat conditions, encompassing both single and coupled pathways. The cooling performance was evaluated by air temperature and outdoor thermal comfort (e.g., Universal Thermal Climate Index, UTCI). The results indicate that façade opening could reduce temperature and improve thermal comfort via enhancing airflow and introducing cooling sources of rivers into the neighbourhood. Cool materials on facades could help reduce temperature while the thermal comfort was not significantly improved.