Static and dynamic strategies for improving daylight use in side-lit classrooms: A case study

Daylight plays a very important role in educational buildings, as it allows to create a pleasant environment, to enhance students' performance and to provide better health conditions to the occupants. For these reasons, and also to save energy in artificial lighting, a great body of literature has dealt with the study of daylight in schools in the past years. Although some quantitative criteria are already in use for assessing daylight effectiveness for several visual tasks - e.g. minimum illuminance values and daylight factors - the distinction between well and badly daylit spaces very often rely on qualitative issues, such as the avoidance of discomfort glare conditions. Moreover, current design practices rely on standard sky patterns, and neglect the specific climate-related issues, and the time varying appraisal of the indoor space. The present paper contributes to this research field by exploring the use of different strategies to enhance daylight levels in a school located in Sicily and selected as a case study. The building is mainly made up of side-lit classrooms, exposed to different orientations. The strategies that are investigated rely both on traditional static devices (e.g. light shelves and reflective glazing) and on more advanced dynamic concepts (e.g. sensor-controlled blinds and electrochromic glazing). All the selected devices are already available on the market. The daylight performance is assessed in the Radiancebased environment provided by DAYSIM 4.0; the model is calibrated upon a measurement campaign. To this aim several Climate Based Daylight Metrics (CBDM) are used to provide a deeper insight of the potentialities of each solution. Further developments are discussed in the conclusions.