Multi-objective optimization of energy, visual, and thermal performance for building envelopes in China?s hot summer and cold winter climate zone

The building envelope design parameters including windows, apertures, shading, and materials have a significant interactive impact on the performance of a building. However, few studies simultaneously optimize these parameters to determine the trade-off solutions between energy consumption, indoor daylighting, and thermal comfort. This study presents a multi-objective optimization (MOO) framework evaluating Useful Daylight Illuminance (UDI), Energy Use In-tensity (EUI), and Thermal Discomfort time Percentage (TDP) with a wide range of parameters to investigate the interactive relationships between multiple building design and performance pa-rameters. The openable-window-area-ratio (OWR), window-wall-ratio (WWR), solar-heat-gain -coefficient (SHGC), louver depth, and wall thickness are integrated into the optimization pro-cess. Taking a building in the Hot Summer and Cold Winter Zone as an example, the results show that a large south-openable-window-area-ratio (OWRs), south-window-to-wall-ratio (WWRs), SHGC, and wall-thickness with a small north-window-wall-ratio (WWRn) and louver depth are most suitable for improving energy performance without sacrificing thermal and visual comfort. The trade-off solution represents noticeable improvements by 18%, 48.4%, and 2.5%, respec-tively, compared with the initial solution in EUI, TDP for the transition seasons, and UDI. The outcomes help the architects to obtain an optimal solution for the design, refurbishment, and renovation of building envelopes in the HSCW zone towards the construction of sustainable cities.