A Daylight Factor for Clear Sky Conditions

Abstract

This paper describes a method for estimating the daylight factor under clear sky conditions. The internal illuminance is divided into two components; light received directly form the window, as a diffuse source, and light reflected from the internal surfaces of the room. The method intended to estimate the internal illuminance as a relative value from the vertical illuminance on the external surface of the vertical window plane. A comparison against computer simulation is used to validate the proposed method.

The purpose of this method is to provide a simple technique that can be used at the early design stages, which can give a preliminary information about daylight performance inside a room.