Performance assessment of partially shaded building-integrated photovoltaic (BIPV) systems in a positive-energy solar energy laboratory building: Architecture perspectives

Abstract

In a positive-energy building (PEB), the energy generation is higherthan the required for the building’s operation, including charging electric vehicles. That is the case of the Fotovoltaica-UFSC Laboratory, a solar energy research building, located in Florianópolis – Brazil (27°S; 48°W), and its electric bus (eBus), supplied by on-site building-integrated (BIPV) and ground-mounted (GM) photovoltaic (PV) systems. In order to assess the performance of BIPV systems from architectural perspectives, three not ideally positioned BIPV systems that use different technologies (c-Si, CdTe and CIGS), tilt angles, and azimuthal deviations were compared with two ideally oriented and tilted GM systems (CdTe), operating at the same warm and sunny site with simultaneous irradiance and energy data collected at high time resolution. All PV systems are installed in an urban environment, with complex aspects of architectural integration, orientation, partial shadings and performance. These aspects were analyzed in detail in this study. In addition, comparisons between real data measurements of all PV systems and PVSyst® software simulations were carried out. Results have shown that BIPV systems presented, in average, higher yields and performance ratios (PRs) than GM systems, and the real measurements validated the expected energy, even for PV systems with complex environment and tilt angle variations connected to the same inverter. In conclusion, PV modules can be more freely used as building skin and/or materials in architectural integration, as BIPV systems can perform well even when not ideally positioned and partially shaded, since the electrical system design supports architectural decisions.