Evaluation of Daylight Performance in Classrooms through Retrofitting in the Composite Climate of Eastern India

Abstract

Natural light has always been a crucial component of classroom design, providing essential lighting for activities like reading and writing. In addition to improving students' circadian, physiological, and psychological well-being, natural light boosts their reading and writing skills, human comfort, and visual perception. It is crucial to keep the classroom well-lit so that students' eyes can focus on their work. The main aim of this study is to evaluate daylight performance in classrooms (architectural studios) through retrofitting at the National Institute of Technology Patna (NITP) campus in Patna, situated within the composite climate zone. The primary objective is to suggest strategies that improve daylighting and visual comfort using spontaneous and climate-based metrics like Useful Daylight Illuminance (UDI), Spatial Daylight Autonomy (SDA), and in-classroom illuminance while keeping desk lighting at 300-500 lux. The study evaluates the effectiveness of clerestory windows, light shelves, solar light tubes, and their combinations in a south-facing studio (classroom). The CIE Standard Sky model is used to replicate India's multifaceted weather. This model includes scenarios with clear, moderate, and cloudy skies. The spatial daylight autonomy (SDA) is increased by 73.68% and 64.42%, respectively, when solar tubes with clerestory windows and solar tubes with lightshelf are used. These methods result in a UDI of 100 and 2000 lux throughout the studio for well over half of the occupied time. In conclusion, these retrofit solutions show potential for increasing natural light and occupants' sense of well-being in design offices in Patna and other parts of India with analogous composite climatic features and architectural styles.