Evaluation of the panel temperature modeling parameters for bifacial photovoltaics with open-rack and vertical installations

Bifacial photovoltaics have rapidly gained significant market share; however, their thermal modeling is lagging behind. Reliable thermal modeling contributes to more robust predictions of the temperature-dependent output power, which emphasizes the need for accurate thermal models for emerging photovoltaic technologies. This study addresses the literature gap related to the validation of thermal models for bifacial photovoltaic (PV) systems. Key novelties include extending the investigation of bifacial PV temperature models to vertical installations and providing insights into their accuracy in challenging Nordic conditions. The applicability of common PV temperature models to bifacial panels was evaluated using experimental data collected from two bifacial systems with vertical and open-rack mounting. Temperature model parameters of Sandia, Faiman and PVsyst models for bifacial panels were extracted from both experimental and computationally simulated temperature data to investigate the use of computational methods in predicting model parameters and panel temperature. The good matching of experimental and simulated parameters with different installation geometries suggests that simulation is a powerful method to identify new parameters for solar devices with different material combinations and cell technologies. Further, one of the key questions was whether standard temperature model parameters - originally developed for monofacial panels - are suitable for bifacial panels. The results revealed that replacing the standard model parameters with bifacial-specific ones enhanced the accuracy of temperature estimation in all cases studied, e.g., for open-rack mounted bifacial panel 0.2−1.2 ^◦C depending on the temperature model. Overall, the findings of the study improve the prediction of power output of bifacial panels in different installations.