An improvement to calculation of lighting energy requirement in the European standard EN 15193:2007

Abstract

Daylighting has a recognized potential for electric energy savings when is used as a complement for artificial lighting. This study reviews the comprehensive calculation method for lighting energy requirement in non-residential buildings introduced by the European Standard EN 15193: 2007 and investigates its feasibility in China. The location of building influences the intensity and duration of daylight. In EN 15193 calculation method, the daylight supply factor, which represents the effect of daylighting on usage of artificial lighting, is the only factor related to location and calculated according to latitude, however the current method (EN15193: 2007) limits the latitude range from 38° to 60° north in Europe, for which the relationship between daylight supply factor and latitude is approximately linear. This study shows that a quadratic relationship needs to be used for a wider range of latitudes. The coefficients of the proposed quadratic relationship are determined for the classified daylight penetration and maintained illuminance level. Various control types are also considered. Prediction of energy requirement for lighting is obtained through building simulation tool EnergyPlus and the effects of some setting factors are discussed.