ANALYSIS OF THERMAL COEFFICIENTS OF BIFACIAL PHOTOVOLTAIC MODULES USING SOLAR SIMULATOR AND NATURAL LIGHTING

Abstract

The conversion of solar energy by photovoltaic modules is dependent on solar radiation, geographic position, climatic conditions, local temperature, among other factors, and these variables directly influence the performance of photovoltaic modules. Among the factors that influence this performance, thermal coefficients (CT) play an important role, as they represent the variation in photovoltaic module parameters as a function of temperature. For this work, a bifacial module was selected to compare the thermal coefficients determined by the indoor and outdoor methods. In the outdoor procedure, the module was characterized on a clear day with solar irradiance greater than 900 W/m2. In the indoor procedure, a thermostatic chamber was created and the SunSim 3c simulator, from the Swiss company Pasan, was used in order to determine the coefficients in the modules' operating range of 25 to 65 °C with irradiance of 1000W/m². In each method, the coefficients α, β and γ were determined. There is a measurable difference between the thermal coefficient values between indoor and outdoor measurements, and the curves obtained using natural lighting were corrected for STC irradiation. As presented in the work, with the tests carried out it was possible to obtain regression lines with coefficient of determination greater than 0.99 in practically all cases, making the results satisfactory. The work presented made it possible to improve and disseminate the methodology for comparing measurements of thermal coefficients in solar simulators and natural lighting, essential procedures in the characterization of photovoltaic devices. Future research can address the behavior of thermal coefficients in more detail and help improve the methodology for obtaining these coefficients more precisely, given their importance in characterizing photovoltaic modules.