Thermal Uniformity Mapping of PV Modules and Plants

The conventional assumption of all the cells in a module and all the modules in a plant is operating at a single temperature. This work indicates that it is not the case. The behavior of temperature distribution of PV cells within a module and of PV modules within a plant is presented. ANOVA, a statistical tool, was used to study the influence of various ambient and design factors on temperature variation. In this study, the effect of thermal non-uniformity on I-V parameters of three different PV technologies (crystalline silicon, CdTe, CIGS) is investigated. The temperature mapping data for two power plants (fixed horizontal-tilt and one-axis) located in a desert climate of Arizona showed that the modules placed in the center of one-axis power plant had higher temperatures, whereas in the fixed-tilt power plant, the modules located in the north-west direction had higher operating temperatures. Higher average operating temperature of modules was observed for the one-axis tracker based plant as compared to the fixed-tilt based plant, thereby a higher degradation rate and a lower lifetime are expected for the 1-axis tracker based modules as compared to the fixed-tilt based modules.