Luminaire position optimisation using radiance based simulation: a test case of a senior living room

The design of a lighting environment is a complex task because of the need to satisfy multiple criteria, which are often in conflict with each other, for example, an adequate level of illumination needs to be maintained in a space to satisfy the requirements for various tasks, while not sacrificing illuminance uniformity or introducing glare and discomfort. The position of luminaires can impact on all of these criteria as well as influence energy consumption of the lighting system, therefore, it is necessary to optimise luminaire position for better performance. Application of computer simulation tools can provide an improved evaluation alternative design decisions to support decision making. However, computer simulation integrated with formal optimisation techniques is not well established within traditional lighting design. An optimisation methodology through computer simulation has been demonstrated in this study to identify optimal luminaire positions within a senior living room. Lighting simulation program Radiance integrated with a Genetic Algorithm (GA) based search technique has been used in this study as an optimisation process. A senior living room comprising two compact fluorescent lamp luminaires was considered as the test scenario. Luminaire position design was subject to meet specific horizontal illuminance uniformity and luminance requirements from guides published by professional organisations. The study demonstrated a methodology to apply formal optimisation technique with Radiance based simulation and the ability to support in decision making. Ray-traced Radiance simulations can be very time consuming, however, with controlled simulation parameters and multi-processor hardware it appears reasonable to integrate formal optimisation techniques with Radiance. The GA based optimisation technique proved to be successful in generating design decision. This paper describes the methodology adopted in detail with advantages and drawbacks, and identifies the potential of the methodology within artificial lighting design.