Engineering topics

Kempe, Michael D

Publications and source records attributed to Kempe, Michael D.

3 records

DOE OSTI2020

Using Meteorological Data to Evaluate Worldwide PV Degradation Rates

Here we automate the process to enable the creation of world maps for specific PV durability metrics. The end goal is to create a tool for the creation of world maps predicting the sensitivity of modules to degradation to inform the development and utilization of module testing standards and to provide information to module designers. TMY (Typical Meteorological Year) Data was aggregated from sites around the world to render insight into factors contributing to the degradation of solar modules. The focus of aggregating data was to create a single dataset to work with utilizing Solar Irradiance values combined with Ambient Temperature, Relative Humidity, Wind Speed and Dew-Point Temperature.

14 SOLAR ENERGY↗

DOE OSTI2020

Development of Testing Methods to Predict Cracking in Photovoltaic Backsheets

In recent years there have been some significant failures of photovoltaic backsheets resulting from inadequacies of design that are not detected in current versions of the qualification standards. In some cases, this has resulted in catastrophic failure in less than 5 y of deployment. In this work, we develop a test sample construction and evaluate accelerated exposure conditions necessary to duplicate the cracking field failure of backsheets using a small and manageable coupon. This sample uses a piece of solder wire to put some controlled topology and stress into the backsheet. Through exposure to different environmental stressors it was found that the application of thermal cycling stresses, after ultraviolet radiation exposure, is of primary importance to duplicate field failures.

14 SOLAR ENERGY↗

DOE OSTI2020

Reproducing the 'Framing' by a Sequential Stress Test

The 'Framing' (local discoloration along cell edges) was induced by a simple sequential accelerated stress test (consisting of hygrothermal- and UV-stressors) applied to the PV modules with high OTR (oxygen transmission rate) backsheet, irrespective of the inclusion of UV-absorber in poly(ethylene-co-vinyl acetate) (EVA) encapsulant. UV-fluorescence imaging of the PV modules suggests that the spatially-inhomogeneous degradation of EVA material under UV-irradiating conditions is correlated to this 'Framing' indicating an underlying common mechanism. These findings would contribute to the development of test procedures to broadly mimic the actual failures observed in fielded PV.

14 SOLAR ENERGY↗