Rahpooye Memari-o Shahrsazi

Rahpooye Memari-o Shahrsazi

Optimizing the Opening Ratio of the Kinetic Sunshade in Order to Improve the Efficiency of Daylight Using Computational Simulation (a case study of an office building in Tehran)

Document Type : Original Article

Authors
1 Department of Architecture, WT.C., Islamic Azad University, Tehran, Iran.
2 Department of Architecture, WT.C., Islamic Azad University, Tehran, Iran (Corresponding author).
3 Department of Architecture, ST.C., Islamic Azad University, Tehran, Iran.
Abstract
Today, the issue of adequate access to daylight has attracted significant attention across architectural, environmental, and health-related disciplines. This interest is driven not only by the necessity of complying with national and international building codes and energy efficiency standards but also by the increasing recognition of daylight as a central factor influencing visual comfort, occupant well-being, and sustainable design. Unlike artificial lighting, daylight is dynamic, constantly changing in intensity, spectrum, and direction, and thus requires careful design strategies to maximize its benefits while mitigating potential drawbacks. Daylight exposure plays a fundamental role in human health and productivity. Numerous studies have demonstrated that sufficient access to natural light regulates circadian rhythms, improves mood, reduces stress, and enhances sleep quality. In addition to these health-related benefits, daylight offers tangible advantages in work environments. Employees exposed to well-distributed daylight report higher levels of productivity, reduced fatigue, less eye strain, and improved cognitive performance compared to those working primarily under artificial lighting. Daylight, therefore, is not merely a design preference but an essential element of healthy, energy-efficient, and high-performance buildings. Access to daylight is particularly relevant in office environments where individuals spend long hours indoors. In such contexts, maintaining an optimal balance between adequate natural light penetration and brightness level regulation becomes crucial for ensuring visual comfort and reducing reliance on artificial lighting systems. Excessive daylight without proper control leads to glare, discomfort, and thermal issues, whereas insufficient daylight results in dimly lit interiors that require constant artificial illumination. To address these concerns, many countries have enacted strict regulations requiring minimum daylight levels in workplaces. These standards aim to guarantee that employees benefit from adequate daylight while minimizing negative effects such as overexposure, glare, and overheating. In rapidly urbanizing cities like Tehran, access to daylight takes on heightened significance. The city’s climatic conditions provide extended periods of direct solar radiation throughout the year, creating both opportunities and challenges for architectural design. With thoughtful planning, architects can harness this abundant natural resource to create comfortable indoor environments and reduce the energy burden of artificial lighting. However, contemporary architectural trends, particularly the widespread use of fully glazed facades in high-rise office buildings, have complicated the daylighting equation. While glass facades allow large quantities of daylight to penetrate indoors, they often result in uneven distribution, excessive glare near windows, and poorly lit areas deeper inside the building. Moreover, uncontrolled solar gain through large glass surfaces significantly raises cooling demands during hot seasons, thereby increasing overall energy consumption and undermining sustainability objectives. These issues underscore the need for advanced architectural solutions that can dynamically regulate daylight penetration. Among the strategies developed in recent years, kinetic shading systems have emerged as an effective method for improving daylight performance in office buildings. Unlike static shading devices, kinetic systems adjust their configuration in real-time in response to environmental variables, such as solar angle, intensity, and occupant needs. Such adaptability ensures that daylight is admitted in controlled amounts, reducing glare and overheating while maintaining optimal illumination levels across the interior space. This research investigates the optimization of kinetic shading devices for office buildings in Tehran, with a focus on maximizing daylight quality and minimizing discomfort. Specifically, the study aims to improve Useful Daylight Illuminance (UDI). This widely recognized metric evaluates the percentage of occupied time when daylight levels are within a comfortable and functional range. By optimizing UDI and simultaneously reducing glare, the research seeks to demonstrate how kinetic shading systems can create visually comfortable and sustainable office environments. To achieve these objectives, advanced simulation tools were employed. Daylight simulations were conducted using the Honeybee and Ladybug plugins within the Grasshopper environment, allowing for a detailed analysis of daylight distribution under various climatic and architectural conditions. Multiple window-to-wall ratio (WWR) scenarios were tested to identify the most effective configuration for maximizing daylight quality. Building on these findings, a prototype kinetic shading device was designed, integrating light-sensitive sensors that allow the system to adapt dynamically to fluctuating daylight conditions. To strengthen the research methodology, it is essential to highlight the role of computational simulation and parametric modeling in shaping the study’s outcomes. Computational daylight simulation enables the evaluation of thousands of design alternatives under realistic climatic conditions, making it possible to identify patterns that would be impossible to observe through traditional methods. Within this framework, parametric modeling in Grasshopper provided a flexible design environment in which geometric variables, such as panel rotation angles, window-to-wall ratios, and surface reflectance, could be systematically adjusted. The integration of optimization tools, such as Wallacei, further enhanced this process by allowing the use of evolutionary algorithms, particularly the genetic algorithm, to search for optimal solutions. Genetic algorithms mimic natural selection by iteratively improving design populations, resulting in the discovery of facade configurations that balance daylight access and glare reduction in this study. This computational and parametric approach demonstrates the transformative potential of digital design in advancing sustainable architecture. The proposed system consists of a mobile sidebar equipped with an electromechanical control mechanism. At its core, a servo motor programmed via an Arduino board responds to signals from a daylight sensor, adjusting the device’s configuration in real time. The shading elements rotate along two axes, providing flexible modulation of solar access. This dual-axis movement allows the system to block excessive direct sunlight during peak hours while permitting diffuse daylight to penetrate deeper into the interior spaces. Weather conditions for Tehran were modeled using EPW files to ensure that simulations accurately reflected local climate data. Additional parameters such as material reflectance, surface properties, and urban context were incorporated using the Wallacei optimization plugin in Grasshopper. A brute-force algorithm was applied to evaluate thousands of design variations and determine the optimal ratio of openings within an 80% transparent facade. Simulation results revealed significant improvements in daylight quality when the optimized kinetic shading system was applied. Specifically, spatial Useful Daylight Illuminance (sUDI) increased by 9.10%, while average Useful Daylight Illuminance (UDIavg) improved by 1.81%. These results highlight the potential of kinetic shading devices to provide more uniform daylight distribution throughout office interiors. By mitigating glare near windows and enhancing daylight penetration in deeper zones, the system successfully balanced illumination levels throughout the building. Beyond daylight optimization, the study highlights additional benefits of dynamic shading systems. By reducing glare and excessive solar gain, the system lowers cooling loads, thereby decreasing overall energy consumption. In doing so, the shading device not only enhances occupant comfort but also contributes to broader sustainability goals and energy efficiency targets set by national and international frameworks. The findings highlight the crucial role of computational design and parametric simulation in driving architectural innovation. The integration of software tools such as Honeybee, Ladybug, and Wallacei enables architects to explore vast design spaces and evaluate complex interactions between geometry, materials, and environmental factors. These technologies facilitate data-driven design decisions that improve both occupant well-being and building performance. This research contributes to the growing field of kinetic architecture, which emphasizes adaptability, responsiveness, and performance-driven design. By demonstrating the effectiveness of kinetic shading systems in optimizing daylight in office spaces, the study provides evidence-based solutions for one of the most pressing challenges in contemporary architectural practice. Moreover, it highlights the necessity of integrating sensor technology, real-time control mechanisms, and advanced simulation tools into facade design to achieve resilient and sustainable buildings. In conclusion, daylight optimization through kinetic shading devices represents a promising approach to creating healthier, more efficient, and sustainable office environments. As urban centers like Tehran continue to grow and embrace modern architectural trends, balancing aesthetic aspirations with environmental performance becomes increasingly urgent. By adopting adaptive facade technologies informed by parametric simulations, architects can design office buildings that not only meet regulatory standards but also enhance occupant well-being, reduce energy consumption, and contribute to long-term sustainability. The research underscores that the future of high-performance office buildings lies at the intersection of responsive design, advanced computation, and environmental responsibility.
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