Validation of the Sandia model with indoor and outdoor measurements for semi-transparent amorphous silicon PV modules

Abstract

This paper presents a set of indoor and outdoor measurement methods and procedures to determine the empirical coefficients of the Sandia Array Performance Model (SAPM) for a semi-transparent amorphous silicon (a-Si) PV module. After determining and inputting the total 39 parameters into the SAPM, the dynamic power output of the a-Si PV module was predicted. In order to validate the accuracy of using SAPM for simulating the energy output of the a-Si PV module, a long-term outdoor testing campaign was conducted. The results indicated that the SAPM with indoor and outdoor measured coefficients could accurately simulate the energy output of the a-Si PV module on sunny days, but it didn't work well on overcast days due to the inappropriate spectral correction as well as the equipment measuring error caused by the intense fluctuation of solar irradiance on overcast days. Specifically, all the errors between the simulated daily energy output and the measured one were less than 4% on sunny days. In order to achieve a better prediction performance for a-Si PV technologies, the SAPM was suggested to incorporate a more comprehensive spectral correction function to correct the impact of solar spectrum on overcast days in future.