Rawāshīn of traditional dwellings in madinah, saudi arabia: integrating aesthetic desire with functional aspects

Background: Rowshan (pl. Rawāshīn) is the projected latticework window, commonly found in façades of traditional dwellings in Madinah. Due to functions that Rowshan provides, such as overlooking the surroundings with complete privacy and controlling natural ventilation and lighting in the dwelling, it achieved a widespread popularity in the traditional architecture of Madinah, which gave the city its unique architectural identity. Aim: We attempt to explore that the Madinah's Rawāshīn carving units are not only esthetic, but also functional for daylight filtering. Our goal is to perform a computer simulation experiment using Velux Daylight Visualizer software and analyze the daylight performance filtered through the front (top) carving units of the Rawāshīn of Madinah. Method: Thirty carving panels of Madinah's Rawāshīn were studied to calculate the solid: void ratios using Image J software. A total of 12 carving units was selected with different solid to void ratios ranged from 0.8:1 to 11.5:1. Our experiment identified the background data such as material specifications, climate input and lighting conditions before the simulation process sets about. The experiment applied a basic geometry model of the standard living room found in Madinah's traditional houses, measuring 4 m (Length) x 3 m (Width) x 3 m (Height) with Rowshan window's (Forehead part of Rowshan) dimensions of 3 m (Width) x 1 m (Height) and window projection of 50 cm out of the wall. The Rowshan window is located 2 m from the floor. The daylight level of 100-300 lux was selected as a target lux level for these experiments. The lux levels were measured three times a day, three seasons a year and over four directions. Results: The average illuminance levels decreased dramatically with the use of Rowshan screens with all ratios compared with base cases with no screen in all orientations and seasons and at three different times of the day. The Rowshan screens with the ratios of (S:V 3.8:1) and (S:V 4.3:1) can provide the recommended levels of daylight (100-300 lux) in the studied room in all orientations and seasons and at three different times of the day. Conclusion: The findings of the present study alter the perception that the interior of the traditional house of Madinah has always been dark and subdued and suggest that the Rawāshīn of Madinah can be presented as potential daylight filters.