NAZAR Research Center MANZAR, the Scientific Journal of landscape 2008-7446 18 75 2026 06 22 Optimal and Efficient Daylight-Oriented Design of the Library Building Façade Structure Using Simulation (Case Study: Zanjan City) Optimal and Efficient Daylight-Oriented Design of the Library Building Façade Structure Using Simulation (Case Study: Zanjan City) 66 75 242499 10.22034/manzar.2026.537861.2369 FA Fereshteh Sadri Department of architecture, Qeshm Branch, Islamic Azad University, Qeshm, Iran Seyed-Majid Mofidi-Shemirani Department of architecture, Energy Architecture Research Center, School of Architecture and Urban Studies, University of Science and Technology, Tehran, Iran Shahnaz Pournaseri Department of Architecture, Faculty of Architecture Engineering and Urban design, Shahid Rajaee Teacher Training University, Tehran, Iran Journal Article 2025 07 30 Architectural design faces the ongoing challenge of improving building performance through the optimization of daylight utilization in façades, particularly in cold climates such as that of Zanjan, which nonetheless exhibits a high potential for effective use of natural daylight during periods of high solar radiation. With the overarching objective of designing a library façade structure through daylight simulation and metaheuristic optimization processes to identify optimal models with the highest level of daylight illuminance efficiency, this study addresses the following question: How can simulation and metaheuristic optimization processes be employed in the design of a library façade structure to enhance daylight performance? The Grasshopper parametric modeling environment and the Ladybug Tools plugin were employed for modeling and simulation. Grasshopper’s parametric framework enables rapid implementation of design variations and real-time observation of their impacts. In the descriptive–analytical phase, SPSS software was used alongside the Kolmogorov–Smirnov test, Pearson correlation analysis, and Partial Least Squares (PLS) modeling. The findings indicate that an optimal daylighting model with the highest daylight performance and the most appropriate illuminance distribution was achieved using an internal light shelf depth of 1.3 m, an external light shelf depth of 0.6 m, and a glazing light transmittance of 0.55. Architectural design faces the ongoing challenge of improving building performance through the optimization of daylight utilization in façades, particularly in cold climates such as that of Zanjan, which nonetheless exhibits a high potential for effective use of natural daylight during periods of high solar radiation. With the overarching objective of designing a library façade structure through daylight simulation and metaheuristic optimization processes to identify optimal models with the highest level of daylight illuminance efficiency, this study addresses the following question: How can simulation and metaheuristic optimization processes be employed in the design of a library façade structure to enhance daylight performance? The Grasshopper parametric modeling environment and the Ladybug Tools plugin were employed for modeling and simulation. Grasshopper’s parametric framework enables rapid implementation of design variations and real-time observation of their impacts. In the descriptive–analytical phase, SPSS software was used alongside the Kolmogorov–Smirnov test, Pearson correlation analysis, and Partial Least Squares (PLS) modeling. The findings indicate that an optimal daylighting model with the highest daylight performance and the most appropriate illuminance distribution was achieved using an internal light shelf depth of 1.3 m, an external light shelf depth of 0.6 m, and a glazing light transmittance of 0.55. http://www.manzar-sj.com/article_242499_52132db54bcd836e71bca1eb102aaf92.pdf