Comparison and Evaluation of Accelerated Aging Tests for Reflectors

Abstract

Accelerated aging testing is used in several industries to estimate the lifetime of products and components. Manufacturers of solar reflector materials usually test the durability of their products following standards from automotive and photovoltaic industry. The testing time and the “pass” or “fail” criteria differ from manufacturer to manufacturer which makes it hard for customers to compare the available mirrors on the market and to select the most durable product based on the data sheets. This paper gives an extensive review of the state of the art of currently applied accelerated aging tests for solar reflectors. The testing conditions of relevant tests are summarized. Based on the experience gained over the last years in the aging laboratory of CIEMAT and DLR, a typical testing program to qualify the durability of reflector materials is being proposed. The appearing degradation of glass and aluminum mirrors under accelerated aging is analyzed and compared to outdoor exposure results.