Development of virtual natural lighting solutions with a simplified view using lighting simulation

Computational building performance simulation can be employed to develop various future solutions. The development of Virtual Natural Lighting Solutions (VNLS), which are systems that artificially provide natural lighting and view comparable to those of real windows and skylights, is steered by modelling them as arrays of small light sources resembling a simplified view of a blue sky and green ground. The lighting simulation tool Radiance is employed to predict the space availability, uniformity, ground light contribution on the ceiling, and probability of discomfort glare. The input variables are “distance between windows”, “tilt angles”, “beam angles”, and “total luminous fluxes of the sky elements”. Sensitivity analysis shows that the total luminous flux positively influences the space availability, the beam angle positively influences the uniformity; and negatively influences average ground light contribution on the ceiling and average probability of discomfort glare. Most of the VNLS models with 114° beam angle perform better on the tested performance indicators than real windows under CIE overcast sky.