INTRODUCTION Market needs and developments Design of presently used and future PV-devices Characterisation of PV-modules OPERATION CONDITIONS Weathering, voltages, soiling, salt impact OUTDOOR MONITORING Sensors for climate-measurements Data-acquisition systems IV-curve measurements EVALUATION OF STRESS CONDITIONS Correlation macro-climate and micro-climate Modelling micro-climate: Module temperature, surface humidity, effective humidity Comparison of the climate at different testing sites and evaluation of stress levels ACCELERATION FACTORS AND TIME TRANSFORMATION FUNCTIONS Acceleration possibilities Acceleration models (time transformation functions) for the different stress factors DEFINITION OF ACCELERATED LIFE TEST (ALT) CONDITIONS FOR DIFFERENT LOCATIONS AND DIFFERENT STRESS FACTORS ALT for tropical, arid, urban, maritime and alpine conditions for UV-load, moisture, humidity, temperature difference, potential induced degradation etc. SINGLE STRESS-FACTOR ALT Requirements for the test equipment Test results Evaluation of the material-specific parameters for the time-transformation function DESIGN OF COMBI-TESTS Simultaneous stress application (UV and humidity, temperature cycling and humidity) Modelling by FEM Requirements to the test equipment Sequential test procedures EVALUATION OF COMBI-TESTS WITH DIFFERENT STRESS LEVELS Service life estimation from combi-tests OUTDOOR EXPOSURE IV-curve monitoring and evaluation Comparison with ALT ANALYSIS OF DEGRADATION PRODUCTS Non-destructive optical methods (spectroscopy, luminescence) Destructive methods (Rheology, SEM/EDX) PROPOSAL FOR ACCELERATED SERVICE LIFE TESTING PROCEDURE MODELLING THE INTEGRAL ENERGY YIELD DURING THE LIFE-TIME Degradation functions from combi-tests Low-light-behaviour Comparison of different modules and systems operating at different locations
Dr.-Ing. Michael K?hl, physicist, has been actively involved in the field of solar energy conversion since 1977. He presently works on service-life analysis of solar collectors and photovoltaic modules in the department Weathering and Reliability at Fraunhofer ISE. He was the coordinator of various successful EU projects on durability testing of solar energy systems, and leader of the German flagship project on durability of PV modules ?PV-Zuverl?ssigkeit?. Up till now he edited two textbooks on the durability of optical materials and on the potential of polymeric materials for solar thermal applications. Sandrin Saile, M.A. joined Fraunhofer ISE's department "Weathering and Reliability" in 2009 where she is responsible for the management and dissemination of the department's research activities. Another field of work is networking in international solar energy committees with a special interest in transdisciplinary sustainability studies and the interconnection between environmental politics, culture and technology.