Vertical Greenery System (VGS) Renovation for Sustainable Arcade-Housing: Building Energy Efficiency Analysis Based on Digital Twin

The Urban Heat Island (UHI) caused by building densification greatly impacts the sustainability of urban residents and the environment. Therefore, it is necessary to utilize the envelope space of buildings for green retrofitting so that they can contribute to mitigating the UHI effect. In particular, green retrofitting of existing and historic buildings has become an effective means to improve the resilience of cities in the modernization process. In this study, Vertical Greenery Systems (VGS) were proposed for traditional commercial and residential buildings in Guangzhou, China. Digital Twin (DT) technology was applied to simulate the VGS construction method and irrigation to visualize the process of VGS construction for old commercial and residential buildings. In addition, the building heat and cooling consumption of the three-dimensional greening of the storage room on the ground floor of the arcade-housing and the living room on the top floor were analyzed according to the thermal parameters of different vertical greening types and different material facades. Finally, the modification of the west and south walls as a greening system was identified as the best energy-saving solution, and this finding provided reasonable theoretical support for the energy-saving design of the three-dimensional greening building of the arched house on South Street, a historic building with a combination of commercial and residential buildings.