A STUDY OF THE DAY LIGHTING PERFORMANCE DUE TO WINDOW SIZE VARIATION IN THE RESIDENTIAL APARTMENTS IN DHAKA

Abstract

Population growth and rapid urbanization create conflict between space-use efficiency and daylight access. Dhaka, the capital of Bangladesh, is experiencing a housing shortage, leading to the construction of high-rise residential units on small lots. As a result, it is confronting an emergency in the housing sector and the resultant is closely built high rise residential apartments on small lands with environmental problems specially lack of daylight. The lack of daylight in these buildings forces the occupants to rely on artificial lighting, thereby increasing their energy consumption. To increase the affordability of the inhabitants, it is necessary to reduce their energy consumption and dependency on artificial lighting through the successful integration of daylight. It is vital to optimize window design for optimal benefit since windows, given their size, orientation, and shading configuration, have a significant impact on day lighting as well as on the building's energy consumption. Through simulation studies, the goal of this research is to identify an effective window category from the window configurations in the setback area. It also investigates the efficiency of window configurations to improve the visual appeal of apartments. This research first conducted a literature analysis and field survey to gather information and select the various window configurations in the adjacent setback area that were suitable for the simulation study. Then, a dynamic annual Climate-Based Daylight Modeling (CBDM) method was used to assess the performance of various window configurations installed at the case apartment, taking into account all weather sky luminance models (i.e., DAYSIM). This study found that the optimal window design had a window-to-wall ratio of 22%–31% and a 450mm horizontal shading device on the south façade. The findings of this study should be useful to architects and designers in creating some criteria for window designs that will improve the lighting environment of residences in Dhaka and other cities in Bangladesh.