Optimum glazing configurations for visual performance in algerian classrooms under mediterranean climate

Abstract

Daylight quality and quantity in Algerian schools show serious problems in ensuring visual comfort of students and teachers. Some problems are due to window design, which leads to excessive amount of sunlight penetration into the classrooms. The consequences are glare and heat gain. This study investigates the effective glazing pattern for classroom to achieve optimum daylight performance and visual comfort in Algerian classrooms. Field measurements of typical classrooms were carried out in a selected school in Algeria during solstice summer (under clear sky condition) and solstice winter (under overcast sky condition). The data of outdoor daylight illuminance were used to validate Integrated Environment Solution Virtual Environment (IESVE) daylight simulation. This study used three different glazing types, namely, clear, tint and reflective glass with different glazing proportions, subsequently, seven patterns of glazing window design were used for an extensive simulation exercise. The results of the investigation from the site measurements show that the work plane illuminance was found to be beyond the range of 300 lux to 500 lux, which exceeded recommended value, except for the south-east orientation with clerestory typology, which were recorded at 2.98% of daylight factor, in contrast the daylight uniformity in tested classrooms is appropriate. Furthermore, the simulation revealed that combination of 75% clear glass and 25% reflective glass with 30% wall-to-window ratio has achieved 41.41% during winter and 47.82% during summer of Useful daylight illuminance. The use of different glazing configurations shows a significant improvement on daylight distribution and the reduction of glare comparing to the reference model. However, such improvement in the quality and quantity of daylighting was inadequate which arises the need of further enhancement.