Comparison and development of daylight simulation software - A case study

Working with daylight simulations on a regular basis, the authors discovered that it is increasingly challenging to achieve daylight criteria in new building projects. In addition to complex building designs, a new European Standard was published in 2018 named EN 17037:2018 Daylight in Buildings, which includes climate-based daylight simulations. These new criteria require a different type of simulation and presentation of results, compared to the simplified method of calculating average daylight factor, which is mostly used today. The authors have created, tested and validated scripts for performing climate-based daylighting simulations, using Rhinoceros and Grasshopper. The script designed for climate-based daylight simulations, showed too extensive differences between supposedly equivalent criteria for daylight factor and daylight autonomy, meaning it can't be applied in construction projects as the only documentation of daylight availability. Further testing and investigation of the climate-based daylight script has to be done, in order to perform correct evaluations of realistic daylighting conditions.