Energy Consumption Optimization and Visual Comfort Performance of Horizontal-Louvered Façades in Office Buildings in Hot-and-Dry Climates

Articles in Press

Document Type : Original Article

Authors
Parastoo Torkzadeh Mahani
Mansour Nikpour
Mohsen Ghasemi
Department of Architrcture, Bam.C., Islamic Azad University, Bam, Iran
10.22034/he.2026.590519.1244
Abstract
In hot-and-dry climates, the growing prevalence of glass-dominated office façades has intensified cooling loads and glare-related problems, creating a profound disjunction between energy efficiency and indoor environmental quality. In the absence of performance-based frameworks for shading-device design, this gap often results in formalistic and technically unsubstantiated design strategies. This study aims to identify Pareto-based archetypes in façades equipped with horizontal louvers for the multi-criteria optimization of energy performance and visual comfort, with a particular focus on the decisive role of the window-to-wall ratio (WWR) and the mediating capacity of louver-blade angle (Alpha). A base office space located in the climate of Kerman, Iran (BWk), was modeled using DesignBuilder, EnergyPlus, and Radiance. Through a full-factorial experimental design, 640 architectural scenarios were generated from combinations of four design variables: WWR, Alpha, Offset, and Spacing. Data analysis was conducted in the R environment using a Generalized Additive Model (GAM) meta-model to evaluate energy use intensity and a composite visual comfort index (VCIndex). This process ultimately led to the extraction of the Pareto front and the clustering of non-dominated design solutions. The findings indicate that WWR redefines the energy regime in a predominantly uniform and upward trajectory, whereas Alpha primarily operates as a thermal modulator and the principal control lever for VC. Analysis of the Pareto front revealed four compromise typologies, among which a WWR range of approximately 40–60% and an Alpha range of approximately 20–40° provided the most effective performance balance. The extraction of three decision-oriented archetypes through clustering and local sensitivity analysis further demonstrated that decision fragility in high-transparency regimes is mainly governed by WWR, while the potential for qualitative improvement in intermediate regimes is directly dependent on Alpha adjustments.
Keywords
Adaptive building envelope
horizontal louver
Pareto front
multi-criteria multi-objective optimization
hot-and-dry climate
Subjects
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Articles in Press, Accepted Manuscript
Available Online from 21 July 2026