Many-objective optimization design of a public building for energy, daylighting and cost performance improvement

The energy performance of buildings especially public buildings needs to be optimized together with environmental, social and cost performance, which can be achieved by the multiobjective optimization method. The traditional building performance simulation (BPS) based multiobjective optimization is time-consuming and inefficient. Practical projects of complex public building design usually involve many-objective optimization problems in which more than three objectives are considered. Using BPS based multiobjective optimization is not sufficient to solve this kind of design problem. This paper aims to propose an artificial neural network (ANN) based many-objective optimization design method, an architect-friendly integrated workflow has been implemented. The proposed method has been applied on a public library building in Changchun city of China to optimize its Energy Use Intensity (EUI), Spatial Daylight Autonomy (sDA), Useful Daylight Illuminance (UDI) and Building Envelope Cost (BEC). The optimization process has obtained 176 non-dominated solutions. By adopting the selected relative optimal solutions, 1.6x10⁵-2.1x10⁵ kWh energy can be saved per year; sDA value and UDI value can be increased by 8.1%-11.0% and 4.3%-4.7% respectively; BEC can be reduced by ¥1.2x10⁵-2.1x10⁵ ($1.7x10⁴-3.0x10⁴). The optimization time has been greatly shortened in this method and the whole process is highly efficient without manual data conversion between different platforms.