Design Optimization of Bifacial Photovoltaic Noise Barriers Using a High Granularity Energy Yield Modelling Approach

Abstract

Integration of bifacial photovoltaic module with a noise barrier (PVNB) has emerged as one of the promising innovation in the building integrated PV (BIPV) system application. By having the advantage to absorb both the light incident from the front and the rear side of the cell, bifacial PV module is suitable for a vertical installation especially when the module is configured to facing west and east direction. However, by nature, PVNB has some limitations that prevent the system to operate in its optimal condition. First, the azimuth of the module cannot be chosen freely, as it has to follow the orientation of the road. Furthermore, the carrying support structures induce an unavoidable self-shading to the rear surface of the bifacial module itself and substantially reduce the power generation of the bifacial PV module.

This project aims to provide a guideline in optimizing bifacial PVNB design to overcome the aforementioned limitations of PVNB application. This study employs a versatile energy yield model that was fully developed in a Python environment. The modeling framework couples a cell-level shading calculation based on vector algebra approach with a high-resolution electrical model that consider bypass diodes configurations in the module. To model the electrical characteristics of bifacial solar cells, two diodes equivalent circuit was modified to have two current sources that represent the contribution of the front and the rear side illuminations. Furthermore, the reliability of the model was proven by the good validation result between the model and long-term experimental data.

The results of this work show that the south-facing bifacial PVNB, in the case of the Netherlands, has the best yield performance when being inclined 15 from vertical. In contrast, the north oriented bifacial PVNB yield more energy when being installed strictly vertical. Whereas, a consistent performance was shown by the east and west facing module when the tilt angle was varied. Furthermore, the result of the annual energy loss caused by shading is in the range of 1% to 12% for different orientations. Six different bypass diodes layout scenarios were considered in the study. It was demonstrated that the energy yield loss induced by the shading can be mitigated significantly by applying a proper bypass diodes configuration in the module. Another efficient alternative to mitigate the shading that was investigated is by placing the cells away from the structures. Though the analysis focus on one specific PVNB design, the insights derived from this study are generally applicable for any future bifacial PVNB projects.