Numerical Analysis of the Performance of an Innovative Daylighting System Named Modified Double Light Pipe

This paper focuses on the performance of an innovative daylighting system named Modified Double Light Pipe (MDLP). It consists of a device integrating a Double Light Pipe (DLP) with a light shelf. The DLP has been created by the authors to enter daylight into two levels underground buildings. It involves an excessive bulk and the risk of glare in the passage environment. The MDLP is an attempt to solve these problems by coupling the DLP and the light shelf technologies. The authors used a numerical approach modeling the MDLP by the software Rhinoceros and simulating its performance by Grasshopper plugins Ladybug and Honeybee. After calibrating the software by the comparison between numerical and experimental data on the DLP, they carried out a numerical analysis on the MDLP in steady-state and dynamic conditions. In steady-state regime, the MDLP performs better than the DLP, giving quite a uniform illuminance distribution on the horizontal work plane. This is confirmed by the results of the dynamic analysis, carried out evaluating the metric Spatial Daylight Autonomy (sDA). Moreover, the risk of glare is avoided by the MDLP, thanks to the presence of the light shelf that prevents the observer from seeing the device directly.