The Significance of Aperture Proportion for the Lighting Behaviour and Transparency of Moshabak

Abstract

Traditional solar screens in Iran (called Moshabak) are architectural devices used mainly in hot-arid regions, with two interrelated functions: controlling the penetration of sunlight and gaze from outside. Consequently, Moshabak plays a significant role in veiling the interior from both and improving the quality of space. This research investigates the significance of aperture proportions for the lighting behaviour and transparency characteristics of Moshabak. The experiments are conducted in a typical residential room, under the sunny and clear sky of Kashan - a typical desert city in Iran. The study is divided into three stages and uses three kinds of Moshabak based on aperture proportions: horizontal, vertical, and square. Stage one of the research focuses on daylighting behaviour, stage two measures annual glare and stage three analyses transparency. For each type of Moshabak three different perforation percentages are used in order to better clarify the performance of different aperture proportions. The research findings show that aperture proportion has a significant impact on the performance of Moshabak. Moreover, Moshabak with horizontal apertures perform better than the rest, while Moshabak with vertical aperture proportions had the lowest performance in the three stages of the study.