Service Lifetime Prediction Of Solar Absorber Surfaces From Results Of Accelerated Ageing Tests

A review of an ongoing case study which aims to develop a methodology for the prediction of the service lifetime of solar absorber coatings is presented. The work forms part of Task X of the International Energy Agency Solar Heating and Cooling Programme which is investigating materials demand and performance in solar energy systems. The case study encompasses the identification of performance criteria for specific applications, e.g. domestic hot water systems, the ageing of absorber materials by accelerated testing of both individual samples and complete collectors, the identification and analysis of degradation mechanisms and failure modes and the development of mathematical models, which input data from accelerated ageing tests, to predict the service lifetime of an absorber coating in a particular end-use application. Commercially available black chrome and nickel-pigmented aluminium oxide selective absorbers are being used as test samples for development of the methodology.