School of Art, Design and Architecture

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Browsing School of Art, Design and Architecture by Author "Abdelwahab, Sahar"

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    Daylight Performance Simulation Prediction Accuracy: Processing Speed Trade-off
    (College Publishing, 2023-06-20) Abdelwahab, Sahar; Rutherford, Peter; Mayhoub, Mohammed
    In daylighting performance simulations of façade systems, a trade-off is often required between processing speed and prediction accuracy. This is particularly relevant at design onset, where plausible simulation outcomes are essential to drive decisions between several alternative façade configurations. To help address this trade-off, this paper presents a sensitivity analysis evaluating the influence of key input parameter settings, namely ambient bounces and grid size, on the convergence of performance outcomes and on simulation run times. The results provide statistical evidence that, although lower precision settings mostly accelerate calculations, they decrease the accuracy of prediction estimates, particularly for complex façades. Conversely, the relative increased accuracy resulting from higher precision simulations might reach a point where differences have a negligible practical impact. The paper concludes with a range of recommendations to support the early-stage selection of parameter settings and contributes to more robust simulation outcomes towards reducing the gap between simulated and measured data.
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    Non-visual effects of lighting characteristics on workers in industrial workplaces.
    (Springer, 2025-07) Abdelwahab, Sahar; Mayhoub, Mohammed; Abdelfattah, Dalia; Eldars, Zakaria; Labib, Rania
    While the impact of lighting environment on comfort has been thoroughly investigated, its impact on human physiology and behaviors is yet to be fully understood. Since the recent discovery of the new class of photoreceptors in the mammalian retina, it has become evident that light is crucial for controlling non-image formation (NIF) processes like circadian rhythms, alertness, well-being, and mood, all of which have an impact on a user's overall comfort. This can be crucial for the indoor working environment, considering also the category of industrial workers which is overlooked in scientific research despite its importance to ensure improved performance and productivity. Therefore, this paper aims to understand the effect of lighting characteristics, duration of exposure to lighting, and timing on the non-visual functions of workers in industrial workplaces. A field study was conducted in three industrial buildings to measure lighting characteristics in winter and summer during different time intervals. Simultaneously, the workers' self-evaluations of five non-visual functions, namely comfort, mood, alertness and satisfaction, were recorded and statistically analyzed. The results also revealed evident effects of both horizontal and vertical lighting, as well as color temperature, on the comfort, mood, and subjective alertness of workers.
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    Users’ window preferences and motivations of shading control: Influence of cultural characteristics
    (Elsevier, 2023-05-25) Abdelwahab, Sahar; Kent, Michael; Mayhoub, Mohammed
    Window shading control is motivated by many reasons. Very few studies consider the influence of non-physical factors that underpin occupant motives for shading control. A candidate reason that concerned this study was cultural differences. Diverging values, beliefs and norms can lead to different design considerations for building architecture to accommodate users’ expectations. This can also influence a wider array of window functions, e.g., daylight access, thermal comfort, natural ventilation, privacy and view out. We investigated the influence of cultural differences in this context. An online survey was administered to collect responses from Arab and non-Arab population groups from across the globe. We compared how occupants would prioritise different window functions in their typical workspaces to better meet their needs across these two groups. The analyses showed that Arab respondents prioritised privacy more than non-Arab respondents. The importance placed on privacy was consistently larger for the Arab group when they worked from their own residential home (r = −0.36), rather than at their office workspace (r = −0.16). Shading control for daylight access was a highly prioritised motive for both groups, which was also equally weighted as the most important reason for both opening and closing window shades with no statistical difference (r = -0.10) found between both groups. Thermal comfort was deemed more important by the Arab respondents, although this may have been caused by climate factors. The study highlights how culture has important implications on window preferences and shading control, which can be influential in the context of design considerations to accommodate user needs.
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    Visual Discomfort Analysis as a Tool to Support Façade Shading Design: A Case Study in the Architectural Design Studio.
    (American Society of Civil Engineers, 2022-02-23) Abdelwahab, Sahar; Sobh, Hesham
    While daylight admittance in educational buildings is of high importance, the associated visual discomfort issues can negatively impact student productivity and well-being. This paper reports the outcomes of a case study of the architectural studios at Al-Azhar University, Cairo, where visual discomfort due to daylight intrusion was reported by 49% of the students, leading to difficulties while performing multiple vertical and horizontal tasks. To address this issue, visual discomfort simulation analyses were conducted for 78 view positions with respect to façade shading systems (fixed shading and dynamic electrochromic glazing). To predict the level of visual discomfort for multiple view targets, three indicators, horizontal illuminance, vertical-eye illuminance, and daylight glare probability, were used. A simulation workflow of daylight and glare was developed to shade each dynamic window individually whenever the defined criteria are met. The results showed evident reductions in the hours of visual discomfort based on the three indicators from 83%, 84%, and 37% to 8%, 19%, and 3%, respectively (southwest), and from 57%, 71%, and 13% to 2%, 10%, and 1%, respectively (northeast). The proposed simulation workflow can be used in future practices to improve façade-shading performance to protect against visual discomfort under similar climatic contexts.