Acceleration Factor Modeling for Degradation Rate Prediction of Photovoltaic Encapsulant Discoloration

An acceleration factor modeling approach to predict the degradation rate for climate-specific encapsulant discoloration in glass/polymer construction modules is presented. The modeling has two different routes of determining the acceleration factor and activation energy for encapsulant browning, which is governed by the degradation data obtained from either the outdoor field or the indoor accelerated UV stress testing. The model developed based on the modified Arrhenius equation uses hourly meteorological data in conjunction with the degradation data. An acceleration factor of 23 is determined for encapsulant browning of c-Si modules exposed to Arizona climate (Hot and Dry) and the degradation rate predicted due only to encapsulant browning is about 0.37±0.04% per year.