Degradation Models of Photovoltaic Module Backsheets Exposed to Diverse Real World Condition

Degradation of polymeric backsheets is a result of accumulated synergetic effects of kinds of environmental stresses. In this study, degradation of the optical properties of 16 commercial photovoltaic module backsheets exposed in 5 different climatic zones was investigated. In addition to yellowness index and gloss measurement, Fourier transform infrared spectroscopy was conducted on the outer layer of a PV backsheet to study the chemical changes during exposure. Several simple linear regression models of yellowness index and gloss as function of degradation factors were developed with the R language. Statistical parameters of the models indicates a good fit to data and a high predictive accuracy.