Document Type : Research Paper
Author
Department of Architecture, Ma.B, Islamic Azad University, Malayer, Iran
Abstract
Solar radiation is one of the most significant factors affecting energy performance in cold climates, and the spatial configuration indices of urban fabric play a direct role in determining the level of solar access to building surfaces. This study aims to analyze the relationship between these indices and solar radiation absorption in the cold climate of Hamadan, Iran. To achieve this, 20 urban fabric typologies were simulated using DesignBuilder software with the EnergyPlus engine, and annual as well as seasonal solar radiation absorption values were calculated. Statistical analyses, including correlation coefficient, analysis of variance (ANOVA), multiple regression, principal component analysis (PCA), and K-means clustering, were conducted in Python.
The results indicated that geometric indices have a statistically significant effect on solar radiation absorption (p < 0.05), and the regression model explained a substantial proportion of the observed variations (R²Total = 0.90, R²Winter = 0.90, R²Annual = 0.90, and R²Summer = 0.79). Three indices—S/A, Ssun/A, and H/Wanua—showed the strongest influence. PCA revealed two principal components explaining 79.35% of the total variance: the first component represented solar exposure capacity/development of physical surface areas, while the second reflected shading intensity. Cluster analysis identified three morphological typologies (shaded, solar-exposed, and open morphology), which exhibited significant differences in winter solar absorption (F = 18.227, p < 0.001).
The main innovation of this study is the introduction of the Seasonal Solar Balance Index (SSBI), which evaluates the balance between maximizing winter solar gain and controlling summer solar exposure, thereby providing a quantitative tool for design decision-making. SSBI showed significant differences among the identified typologies, with the “solar-exposed” typology achieving the highest value and the best overall seasonal performance balance. This typology, through an appropriate combination of envelope surface development and controlled shaded surfaces, enhances winter solar access while relatively limiting excessive summer radiation.
These findings provide a quantitative framework for guiding urban design in cold climates. It is recommended that urban designers prioritize greater solar exposure and controlled shaded surface ratios within street networks and mass–space configurations, while policymakers integrate the proposed thresholds into local design guidelines to ensure seasonal balance in solar performance at the urban fabric scale.
Keywords
- Urban fabric morphology
- geometric indices
- solar radiation absorption
- cold climate of Hamadan
- SSBI index
Main Subjects
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