Design, implementation and evaluation of a daylight estimation tool using 3D city model data

Abstract: Solar energy is an important component of sustainable urban development. However, it is still not reaching its full potential due to several reasons. One of them is a lack of free tools based on open geodata capable of estimating solar energy (daylight) metrics on building features, e.g.,windows, in the early stages of the urban planning process. To fill this gap, a design and implementation of the “Daylight Estimation Tool” is proposed in this thesis project. All inputs required by the tool can be created in free and open-source software. The tool uses two primary data sources – UMEP (Lindberg et al., 2015) energy simulation output files and a 3D city model. The tool performs several operations resulting in the estimation of solar irradiance values for window features, the geometry of which is retrieved from the 3D city model. The output of the tool is an extended city model as well as a report with information about irradiance values on building surfaces. The extension of a 3D city model is done by adding the attributes to the semantic objects and by adding material objects for visualization purposes. The tool is evaluated against the test dataset created by the UMEP simulation tool and online VGI3D platform (Fan et al., 2021). The tool itself is a free and open-source project licensed under an MIT license and available on GitHub.