Investigating Daylighting Effectiveness And Occupants? Visual Comfort Of Fa?? Ade In Office Buildings In Wolaita Sodo Town, Ethiopia.

Abstract

Most people spent over 85% of their lives inside buildings. In case, one of the determinants of human performance in indoor environment is quality of light. These realities of modern life and the increasing need to better understanding created the opportunities to study and improve the health of building occupants (i.e. lighting, comfort and daylighting strategies). The introduction of daylight into buildings has great potential to positively impact building occupants and to reduce energy use. Nonetheless, if daylighting designs are poorly perceived, the luminous environment may lead to issues such as visual discomfort/ glare, headaches, or eyestrain and dissatisfaction with job performances. In case, to design and operate a building to make full use of daylight with creating comfortable visual environments at offices remains a challenge. The purpose of this research was to examine effectiveness of daylighting and visual comfort with facade in three office buildings in Wolaita Sodo town, with a wet summers and dry winters semi-arid climate. The investigation was conducted using three methods; -subjective evaluation, field measurements/lux meter and simulation tools. In total, 55 occupants were responded form three buildings. This paper discusses findings from evaluation of occupants' subjective visual comfort perceptions (thermal was not scope of study), occupants? satisfactions with daylight & workspaces, productivity, shading control of luminous environments. 68% of the participants complained about the visual environment. 60% of the participants experienced direct sunlight on their workspaces/ faces and ranked for disturbing or intolerable glare. The discomfort periods of visual environments were occurred when it was over comfortable threshold zone in office spaces (500lx) and under (300lx). for instance, on clear sky, Glare/bright space (>80% of day) and Gloomy /darken space (<20%) for <4m from window. Generally, the concerned with the role of building skins (glazing, solar shadings) in relation to natural light and the importance of sustainable facade as this plays an important role in subtropical climates, like Wolaita Sodo where the facade has a direct impact on the visual comfort and indoor environmental quality. Current glazing and building facades mostly used in case buildings were resulted with various complaints. Therefore, as core concept of environmental architecture, it is crucial that designers understand daylighting strategies, shading, and corresponding human perceptions of comfort.