Thermal properties of photovoltaic modules: the double function of BIPV systems

Resumen

Building Integrated Photovoltaics (BIPV) play a crucial role to achieve the target of Net Zero Energy Building (NZEB). However, when a solar panel is fully integrated into the building envelope, its electrical and thermal behavior change compared to open-rack systems. BIPV projects tested and reproducing under real working conditions are essential to validate models and increase the penetration of BIPV systems. This article present the results of four simple squared structures with the same volume and with five faces (base excluded) made by PV modules from four different PV technologies: c-Si, two thin film (a-Si and CdTe) and an emergent organic photovoltaic (OPV). These structures, named PV-Cubes, are monitored with automated data acquisition of several thermal parameters. The results indicate that the highest measured temperature corresponds to the a-Si cube, however under diffuse conditions the a-Si panel has better performance from the thermal point of view. Furthermore, it is highlighted that the temperature differences of inner and outer faces of each panel (and for all face orientations) show a hysteresis when represented against incident irradiation, demonstrating a thermal inertia along a day, which has to be considered both for electrical power delivery and for thermal isolation in the building. The results of this research provide high quality experimental data and contributes to better understanding of BIPV systems from a dual-function perspective.