Building-Integrated Photovoltaic Performance Modelling: Evaluation of the System Advisor Model (SAM) Based on Experimental Data from a Grid-Connected Rainscreen System

As global efforts on the electrification of the built environment intensify, buildings are expected to become energy-flexible and provide different services to the grid, including onsite electricity generation. Distributed energy sources such as building-integrated photovoltaics (BIPV) have a key role to play in this transition. Thus, it is essential for building professionals to use accurate and reliable tools to predict the energy performance of these installations. BIPV refers to photovoltaic systems that can replace conventional building components. The electrical performance of BIPV can differ from that of conventional PV due to their tilt angles, poorer rear ventilation, and partial shading by the surroundings. The objective of this study is to review existing performance models and evaluate their applicability to BIPV. In this study, the performance of a 5.3 kWp south-east facing BIPV rainscreen system of an institutional building was evaluated for one year on the basis of monitored data. High-resolution meteorological, electrical, and surface temperature data were collected and analysed. A model was created based on the BIPV system specifications using the NREL System Advisor Model (SAM). The analysis revealed that SAM can generate accurate and reliable data when it comes to predicting the electricity-generating and temperature behaviour of a BIPV façade, with an overall coefficient of determination (R2) ranging from 48 to 95%, depending on the simulation timestep used.