Comprehensive building envelope optimization: Improving energy, daylight, and thermal comfort performance of the dwelling unit

Abstract

The majority of the conducted researches in the past few years examined daylight and energy usage as the primary goals considering the specific parameters of the building envelope. Despite the great importance of interior thermal comfort and its substantial impact on other objectives, it rarely accounted as the third objective alongside energy and daylight performance. The current study presents a multi-objective optimization analysis evaluating Energy Usage Intensity (EUI), Useful Daylight Illuminance (UDI), and Predicted Percentage of Dissatisfaction (PPD) with a wide range of envelope parameters to clarify the relationships between the objectives and the parameters with objectives. The envelope variables include the wall and roof construction and insulation (type and thickness), skylight, Window-to-Wall Ratio (WWR), and external shading device (number, depth, and angle). The case study is a real-world duplex house modeled without simplification considering surrounding areas in a humid subtropical/Mediterranean climate. During the optimization process, 2600 solutions are generated, then the optimal solutions are selected for comparison purposes. The results emphasize the importance of the balance between parameters to provide efficient performance, particularly for the PPD. Accordingly, solar radiation penetration into interior places in cold months results in a lower PPD value. Furthermore, a correlation can be seen between parameters regarding daylight and energy distribution. The building insulation, wall construction, WWR, shading features, and skylight orientation are immensely influential on all three objectives. Compared with the original model, the balanced model indicates an improvement in the EUI, UDI, and PPD by 36%, nearly 5%, and 14%, respectively. The results of this investigation have the potential to be used in the early stage of design, refurbishment, and renovation cases.