Effect of air mass factor on the performance of different type of PV modules

The paper presents the results of the outdoor performance tests made on several types of commercial PV modules. These were both single crystal and multicrystalline Si modules as well as thin-film CIS and two amorphous Si devices - single junction, marked as SJ, and triple junction, marked as TJ, respectively. Special emphasis has been put on the effects related to actual solar spectrum and meteorological parameters like air humidity and ambient temperature that may influence it. Besides short term changes that could be observed during a single day, also the results collected for more than one year of monitoring are presented. Additionally, the results of some theoretical calculations supplementing the experimental data are given. Performance of thin-film CIS module and both a-Si modules after well visible period of degradation seems to be more affected by weather and climatic conditions than the modules made of crystalline Si cells.