Yoon Han
The paper examines four operational concepts in built environment practice—building metabolism, bioclimatic design, urban green–grey integration, and urban metabolism—through the Social–Ecological–Technological Systems (SETS) perspective. Though disciplinarily distinct, all four engage with the regulation, optimisation, and transformation of material and energy flows in urban systems. Expressed as SETS configurations, the otherwise incommensurable concepts fall on a single scale, not as alternatives but as a traversable sequence in which each retains what the previous one establishes while extending the system boundary, from stock and flow accounting within buildings to the coordination of flows across the city.
The sequence exhibits a dual trajectory. SETS configurations rebalance, from the socio-technical optimisation of building metabolism towards systems where ecological processes become co-constitutive of infrastructural operation. Resource flows meanwhile become less linear: throughput is first made visible, then reduced in volume by bioclimatic demand reduction, then partially re-routed through ecological cycles in green–grey integration, and finally coordinated across subsystems by urban metabolism, which remains diagnostic, not prescriptive. The ordering also exposes where the pathway stops: its advances concentrate on the ecological and technological dimensions while the social dimension remains largely unchanged, inhabitants figuring throughout as parameters, not as agents in the organisation of flows.
Because reaching circular regenerative urban environments (e.g. circular urbanism, regenerative design) requires systemic changes that entrenched regimes, fragmented governance, and sector-specific evaluation frameworks resist, the paper argues that operational models compatible with existing planning and professional practices can serve as bridging mechanisms towards them. The four form one such pathway towards circular regenerative urbanism; the residual work, social and institutional more than technical, marks where analytical innovation and adaptive governance must take over.
Keywords: urban systems; social-ecological-technological systems (SETS); material circularity; urban metabolism; building metabolism; bioclimatic design; green–grey integration; circular urbanism; regenerative design