Abstract
This paper addresses the imperative goal of achieving carbon neutrality in Tokyo’s historic Nihonbashi district by 2050. The proposal of a systems design model based on the reconstruction and renovation of the existing built environment through design changes enables meeting the goals of net-zero emissions targets. Our study proposes the integration of 3D modeling techniques and scenarios generation for complex urban neighborhood systems and explores design decisions aimed at further reducing carbon emissions. By leveraging advanced technologies, such as digital urban modeling tools (building energy modeling and design generation based on Rhino 3D, Grasshopper, Ladybug, Climate Studio, and ArcGIS) as well as systems architecting tools (including morphological matrix, alternative concepts analysis, and model-based systems engineering, MBSE), we seek to provide a comprehensive framework for decision-makers and urban planners to assess the environmental impact of design choices. Our approach involves developing a digital representation of the Nihonbashi district, incorporating various architectural and environmental parameters. Through simulation, we analyze the potential carbon reduction benefits of alternative design interventions, including the following variables: materiality (structure), building density, building type/use, facade, and renewable energy integration. The findings of our research highlight the potential for significant carbon emission reductions through innovative design decisions. By quantifying the environmental impact of various design scenarios, decision-makers can make informed choices that align with the district’s carbon neutrality objectives. Additionally, our study investigates the economic viability and feasibility, as well as the equitable impacts of implementing these design changes, considering factors such as cost, construction logistics, and stakeholder involvement. This paper contributes to the existing body of knowledge related to planning decision support systems by exploring the role of digital modeling as a transformative tool of urban planning for carbon neutrality. By emphasizing the importance of incorporating design changes to address carbon emissions, we aim to provide actionable insights for urban development in Nihonbashi and inspire similar initiatives worldwide.