Energy rating of various PV module technologies in two extreme climates, tropical and cold-arid climate

The authors set up an outdoor measurement system in Bangkok, Thailand for taking I-V characteristics of thirty PV modules (from ten manufactures) with meteorological data including solar spectrum irradiance in January 2006, and also set up a similar system in Gobi desert in Mongolia in 2002 and 2005. The change in spectrum irradiance mainly caused by the seasonal change in humidity affected the seasonal performance of a-Si considerably, though the effect of temperature change on the seasonal performance was relatively slight. Indices for characterizing solar spectrum and module temperature for energy ratings were introduced, and a simple regression model for predicting daily energy output of PV modules was verified.