Regeneration diagnosis for the service lifespans of residential buildings on a circular economy perspective

Abstract

As urbanized areas progress into the era of stock, an immense number of existing residential buildings (RBs) are destined to undergo replacement and renovation. The irrational decision of urban renewal led to serious economic waste and environmental unsustainability. In this regard, this study proposes and validates a method for regeneration diagnosis and optimal regeneration of RBs based on circular economy (CE) theory. A hybrid diagnostic tool of life cycle cost (LCC)-life cycle assessment (LCA) model to systematically evaluate the economic and environmental impact of RBs throughout the circular lifecycle was proposed. On this basis, with the minimum average annual economic and environmental impact as the objective function, the optimal dynamic regeneration cycle of RBs is obtained using a multi-objective optimization method. The results of the case study show that: (1) The discount rate and deterioration rate changes the development tendency of economic and environmental data, which brings a new regenerating time point, (2) the economic impact of RBs’ regeneration tends to be more pronounced during the intermediate stages, while the environmental impact becomes more significant in the later stages, (3) the environmental benefits of regeneration outweigh the economic benefits, (4) the regeneration of all building elements at the local optimal level leads to enhanced comprehensive benefits compared to multiple regenerations of a single building element. The feasibility of the method employed in this study has been corroborated by practical case studies. This approach transcends the limitations of quantitative analysis in assessing the regeneration of RBs in a circular lifecycle and offers profound implications for the development of urban renewal and sustainable strategies.