Thermal performance of PV modules as building elements: Analysis under real operating conditions of different technologies

Building integrated photovoltaics (BIPV) represents a strategic part of the future building vision with a huge potential driven by the growing shift towards renewable energy resources. However, transforming building surfaces into active electricity generators must consider the thermal behaviour of photovoltaic (PV) panels since it affects both the power conversion efficiency of the PV modules and the thermal comfort of the building. Although several methods have been developed for the evaluation of the thermal performance of the PV modules, at present, no clear consensus exist on which model fits better for this application considering different PV technologies and real operating conditions. This work presents the study of the thermal behaviour of four different PV technologies (polycrystalline silicon, cadmium telluride, amorphous silicon; and organic PV) based on measurements collected by an experimental system located in Murcia (southeast of Spain) during a full year. Two prediction models to estimate the operating cell temperatures of PV modules (NOCT and Sandia) have been evaluated for their suitability in BIPV systems. The results show how both models strongly depend on the incident solar irradiance magnitude and orientation. Furthermore, the correlation between ambient and module temperature difference and the in-plane irradiance shows a thermal hysteresis effect that is mostly independent of the technology but strongly dependent on orientation, with special impact for east and west faces. The results should be taken into consideration for more accurate estimations of electricity production of BIPV systems. (C) 2020 Elsevier B.V. All rights reserved.