A Comparison of Different Rear Irradiation Modeling Methods in a Bifacial PV System

Bifacial module technology is increasingly used in a multitude of fields (building integrated photovoltaic, agrivoltaic systems, and PV plants). In particular, this type of module can be a better alternative for efficient agri-greenhouses than monofacial ones as a result of the additional energy gain from the rear face. Also, the evaluation of the additional energy gain generated by bifacial modules is crucial for the design and installation of photovoltaic plants based on this technology. This gain depends mainly on the quantification of the irradiation incident on the rear side of the bifacial module. As a result, various optical models, such as those based on the approach of view factors (the average diffused masking angle) and ray tracing were developed to evaluate the irradiation received by the rear face of bifacial modules. In this study, a comparison between the obtained results from the different software tools (SAM, bifacialvf, 3DViewFactor, Bifacial_Radiance) was carried out for an elevated bifacial photovoltaic system composed of three rows. The results show that the radiation received in the three rows is nonuniform. The variation depends on the parameters of the system (tilt angle, ground clearance height, row spacing and Albedo). It was found that the second row was most affected by these parameters. In addition, the results obtained using different softwares showed a difference that can reach about 12% in the case of the Bifacial Radiance and 3DViewFactor.