Evaluating daylight performance of light shelves combined with external blinds in south-facing classrooms in Athens, Greece

The contribution of daylight to energy efficient building design and to the creation of a pleasant environment that provides visual comfort to its users has been a subject of study for years. This paper addresses the way in which daylight can be efficiently used in a typical classroom in Athens, Greece, by improving its distribution in the space and providing shade. Based on the conclusions drawn from the literature review, the system that is chosen for study consists of a light shelf (for shading and light redirection) and semi-transparent movable external blinds (for more shading, adjusted to the occupants' needs), which are mounted on the glazing of a south-facing classroom. The experimental study consists of six stages, all performed in Radiance software. The individual results and conclusions lead to the definition of the optimum characteristics of the system, including the light shelf's width, mounting height, inclination and reflection index, which upgrade the daylight performance in the space under study. (C) 2016 Elsevier B.V. All rights reserved.