TITLE:
Optimizing Passive Design Elements to Improve Building Energy Efficiency in Kabul, Afghanistan
AUTHORS:
Mustafa Karimi, Tomoyuki Chikamoto, Myonghyang Lee
KEYWORDS:
Building Orientation, Window-to-Wall Ratio, Passive Solar Design, Energy Simulation, Sustainability, Kabul, Afghanistan
JOURNAL NAME:
Journal of Building Construction and Planning Research,
Vol.13 No.1,
March
12,
2025
ABSTRACT: This study explores the potential of passive solar strategies to enhance the energy performance of residential buildings in Kabul, Afghanistan, by analyzing four critical design parameters: building orientation, window-to-wall ratio (WWR), floor-to-ceiling height, and overhang size, considering multiple glazing types (single, double, and triple). Utilizing BEoptTM energy simulation software, the research evaluates the impact of these parameters on heating and cooling energy demands across varying configurations. The findings indicate that the south orientation achieves the lowest total energy demand, while the northwest-facing façade exhibits the highest energy demand, irrespective of glazing type, revealing energy savings of up to 101.7% between the best and worst orientations. Regarding the WWR, significant energy savings are observed only for south-facing windows, with optimal ratios of 25%, 35%, and 55% for single-, double-, and triple-glazed windows, respectively. These configurations yield energy savings of 25.7%, 35.2%, and 36% compared to windowless façades. In contrast, increasing window sizes in other orientations (north, east, and west) leads to higher overall energy consumption. Floor-to-ceiling height, which influences the volume of conditioned space and heat stratification, increases total energy consumption by an average of 8%, 6.5%, and 5.1% for single-, double-, and triple-glazed windows, respectively, with each 30.5 cm (1 foot) increase. Additionally, south-facing windows without overhangs maximize winter solar gains and offer superior energy performance, whereas overhangs reduce efficiency by obstructing beneficial sunlight leading to higher energy demand. These findings provide actionable insights for architects and builders in Kabul and offer guidance for designing energy-efficient residential buildings in similar climates.