The Role of Orosi’s Islamic Geometric Patterns in the Building Façade Design for Improving Occupants’ Daylight Performance

The form of the building facade significantly affects the amount of useful daylight admitted in the interior space. Striking a balance between the visual comforts of occupants and taking advantage of daylight is always a challenge and, therefore, investigating complex, geometric forms of Orosi patterns can be an effective way of improving visual comfort alongside the aesthetic aspects. Due to intense radiation in the hot and arid climate of Iran, passive strategies were employed for controlling natural light. As a daylight-related component in Iranian vernacular architecture, Orosi offers different functions which are divided into three categories, namely daylight performance, thermal performance, and decorative role. In an attempt to improve indoor daylighting and visual comfort of occupants, this paper investigated, for the first time, the daylight performance of different Islamic geometric patterns (IGPs) used in Orosies with different thicknesses on the West and south facade. To this end, a total number of twelve traditional courtyard houses were studied through a field survey to extract different types of IGPs used in the Orosies. Finally, a grid-based simulation analyzed the indoor daylight conditions through climatic-luminance based metrics. The findings confirmed the daylight performance of the IGPs as a complex geometric form used for the facades. Compared to the base case on the South façade, all the studied patterns offered a significant potential to address the requirements of visual comforts. Additionally, the results revealed the considerable effect of thickness on the daylight performance of IGPs. Based on the results, the 10 and 15 cm thicknesses, showed better results, in comparison with the 5 cm thickness. The 8-Point-Star, as the best choice for the South façade, kept the metrics within an adequate range for occupants. The 8-Point-Star provided DA, UDI, EUDI, and sDA values of 80.18%, 76.65%, 12,22%, 44,6 respectively for thicknesses of 10 cm in the bright layer, which is more than twice the UDI value provided by the base model. Furthermore, the results confirmed the poor performance of IGPs on the West façade, particularly with thicknesses of 10 and 15 cm. The 8-Point-Star and 8-Fold-Rossette, as the best choices, improved the daylight performance of the West façade and prevented visual discomfort for occupants