Durability Studies of Solar Reflector Materials Exposed to Environmental Stresses

Methods that allow accurate prediction of service lifetimes need to be developed and demonstrated to spur the commercialization of solar reflector materials and systems. Wtihout confident knowledge of service lifteimes, uncertainties in life cycle cost and warranty projections will significantly limit the economic viability of solar concentrators. To assure general and robust usefulness, methodsshould be based on correlations between accelerated, laboratory-controlled environmental stress factors and actual deployment conditions for a variety of applicable geographical locations. Accelerated experiments have identified the key stress factors of UV radiation, temperature, and relative humidity, and their effect on loss of performance, for a particular class of reflector materials. Amodel is proposed that allows prediction of the time dependent degradation of such materials as an analytic function of combined applied stresses. The model is shown to provide excellent agreement with measured performance data and provides a strong basis for future comparisons with data collected in field tests.