Practical Comparison between View Factor Method and Ray-Tracing Method for Bifacial PV System Yield Prediciton

View-factor and ray-tracing are the most commonly used methods to estimate the irradiance incident on the rear side of modules in bifacial PV systems. The view-factor method is used in well-known commercial software, such as PVsyst and SAM. On the other hand, the ray-tracing method is not commercialized yet and is rather complicated and time consuming to use. However, it is more accurate and suitable for complicated geometries. Despite the mentioned advantages and disadvantages in both models, a practical comparison of bifacial PV yield predictions using both methods on a system level is not available in the literature to the best knowledge of the authors. This paper determines the accuracy of the view factor method with respect to ray-tracing. The rear-side irradiance is significantly lower in view factor method and mean bias error (MBE) is up to 19.7 % lower than in ray-tracing method.