A comprehensive validation of an electrical–thermal model for bifacial photovoltaic modules

This study focuses on the representation of bifacial photovoltaic modules using electrical and thermal models. Various approaches in the literature propose modifications, such as incorporating rear-side irradiance, adjusting resistive parameters and diode currents, and adding series resistances. However, experimental evidence for evaluating these approaches under different operating conditions remains limited. Moreover, most studies concentrate on the maximum power point without analyzing the full IV curve, which can reveal shading-induced steps associated with rear-side frame shading in commercial photovoltaic modules. An integrated electrical and thermal model for bifacial modules is proposed, employing a single-diode model for the electrical component. To represent bifacial behavior, parameters for both front and rear sides are integrated using irradiance-based rescaling, including temperature corrections to derive IV curves and estimate power output. For the thermal component, two approaches are employed, culminating in a hybrid model that selects between the Gu and Faiman formulations according to irradiance conditions. Irradiance estimation is performed using Bifacial Radiance software. Validation of the proposed model involves two tests. The first employs laboratory measurements using an A+A+A+ solar simulator to generate IV curves under controlled conditions. The second uses an outdoor setup with a vertically oriented, east–west bifacial module that continuously monitors irradiance, temperature, voltage, and current. The proposed electrical model reproduced the indoor IV curves with deviations of approximately 3% at the maximum power point. Under outdoor conditions, additional discrepancies were observed and were associated with irradiance variability, temporal resolution, and shading from the module frame and surrounding structure.