Simple scale models for daylighting design: Analysis of sources of error in illuminance predictiont

Abstract

This paper reports on the findings and implications of a study of the performance of small-scale physical lighting models. It seeks to clarify the primary causes of divergence between model and real building performance and to discuss the main factors involved in achieving accurate physical representations of buildings. A brief account of a case study is given in which an existing museum building was modelled. The methodology adopted is described and an analysis of the model's divergent performance from that of the building is made. This is followed by an examination of the core issues in scale modelling for accurate daylight prediction. The latter focuses on sources of error in the model's representation of dimensions and photometric properties. Drawing on examples from the case study it is suggested that the size of such errors may account for the apparently persistent overestimation of illuminance levels by lighting models. Proposals are suggested for dealing with error ranges in small-scale model performance.