Modeling and simulation of radiation in modern urban spaces

• Applicant: Professorin Dr.-Ing. Sabine Hoffmann
• Subject Area: Construction Material Sciences, Chemistry, Building Physics ; City Planning, Spatial Planning, Transportation and Infrastructure Planning, Landscape Planning
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 524069026

Radiation has a significant impact on vital aspects of human existence on earth. Without radiation humankind could not exist. Furthermore it is responsible for our sense of vision and thermal perception. The transfer of radiative flux is affected by several factors such as the sun, the sky, buildings and vegetation. Compared to rural areas, urban spaces have a far higher number of man-made surfaces that affect radiative transfer. Additionally, radiative transfer has a far greater impact on energy consumption and local microclimates of urban areas than that of rural areas. Based on the literature review, the modeling methods and simulation techniques that constitute the current state of the art are not suited to represent the complexity of modern urban morphologies in its entirety. The numerical models for urban surfaces are based on simplistic assumptions, and numerical models used to incorporate the sun and sky lack the adequate resolution for precise calculation of radiation. Furthermore, conventional simulation techniques can only accommodate simplistic material models and low resolution sky models. The proposed research project will address these deficiencies and develop appropriate solutions: A unified and comprehensive material model for urban surfaces will be developed. It will account for a variety of materials with different optical and thermal properties, including special materials such as vegetation, for which until now no general description exists. A generalized sky model for urban radiation modeling will be created. Based on a sensitivity analysis, an adequate discretization of the sky model will be identified and complemented by an appropriate consideration of the precise sun position. Finally, simulation techniques that couple shortwave and longwave radiation will be developed. The simulation techniques will be validated experimentally and compared with existing approaches regarding accuracy and computational effort. The goal of this project is hence to formulate a comprehensive framework of modeling and simulation techniques to accurately estimate radiation exchange in modern urban spaces. The outcome of the project will provide a basis to precisely assess the impact of changing climatic conditions and propose possible future strategies for mitigation and adaptation in the urban environment.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partner: Greg Ward, Ph.D.