Urban form and carbon emissions: an evaluation tool for computational urban design

Cities play a crucial role in global carbon emissions, underscoring the significance of quantifying carbon impacts in urban design. This necessitates a shift towards the paradigm of computational urban design. Previous research in quantitative carbon evaluation for urban design has exhibited shortcomings in comprehensiveness and operability. Moreover, evaluation of travel carbon emissions at this scale is limited especially. This study strives to develop a comprehensive carbon evaluation tool to support computational urban design, while addressing gaps in travel carbon evaluation. The proposed carbon evaluation tool integrates three dimensions: building carbon emissions, travel carbon emissions, and green space carbon sinks. Building carbon emissions are evaluated through energy simulations using software tools EnergyPlus. The calculation of travel carbon emissions is based on the prediction of travel modes for specific travel distances. The prediction is achieved through Stated Preference (SP) methods and multiple logistic regression. Green space carbon sinks are quantified using empirical data. Based on these aspects, a carbon evaluation plugin is developed on the Grasshopper platform to support urban design practices. Subsequently, the research applies this tool to a community in Chengdu, China, showcasing its effectiveness in supporting carbon assessment and optimization. In conclusion, the developed comprehensive carbon evaluation tool offers robust support for carbon optimization in urban design practice, and simultaneously contributes to the evaluation of travel carbon emissions at the urban design scale.