Daylight factor simulations – How close do simulation beginners ‘really’ get?

The daylight factor is usually one of the first daylight performance measures that simulation newcomers calculate. Apart from the intrinsic limitations of the daylight factor as a meaningful daylighting performance metric, little work has been done in the past as to how accurate one can actually expect simulation novices to simulate the daylight factor compared to an expert modeler. This paper presents the comparison of daylight factor predictions from a ‘best practice’ model of an L-shaped perimeter classroom to a total of 69 novice/student models. In all cases the models were prepared in ECOTECT and simulated in RADIANCE. The paper discusses common mistakes that simulation beginners make when carrying out a daylight simulation, how close their simulation results were compared to the best practice model, and how software developers and educators could potentially guide users to avoid making these mistakes. In addition, a comparison of simulation results obtained with ECOTECT’s buildin split flux method as opposed to RADIANCE is carried out for the 69 models in order to quantify in how far using a less reliable simulation engine compromises the accuracy of a simulation.