SYMPOSIA PAPER Published: 01 January 1996

Development of a Methodology for Service Lifetime Prediction of Renewable Energy Devices


Emerging advanced multilayer renewable energy devices, such as reflector materials and photovoltaic modules, are expected to exhibit significantly increased service lifetimes compared to existing devices. Such devices must be capable of 20 to 30 years of operation under harsh outdoor weathering conditions. Industrial manufacturers cannot afford to wait extended periods of time to determine whether such lifetimes are realistic. Consequently, a flexible, robust, and accurate method for predicting the service lifetime of such devices is essential. Two requirements for developing such a method are first, to correlate the accelerated lifetime test methods with anticipated life under real-world operating environments; and second, to establish statistical models for predicting service lifetimes based on environmental stress factors.

The relative significance of the weathering stress factors ultraviolet light (UV), temperature (T), and relative humidity (RH) was ascertained. Optical properties of new reflector materials were measured and their loss of performance with exposure time was modelled as a function of an appropriate combination of stress factors. Then, the functional relationship between performance measurements and time in accelerated lifetime tests was investigated. The basic framework of this approach is SPt analysis because it intends to explain the bridge functions from Stresses (S) to Performance (P) and from Performance to lifetime (t) of the materials. The results show that the cumulative dosage of ultraviolet radiation between 290–320 nm (UV-B) with synergistic effects of T and RH is a very critical factor in inducing performance loss. Finally, the SPt model developed for accelerated laboratory data was verified for data obtained from outdoor sites, and excellent agreement was found.

Author Information

Kim, H-M
National Renewable Energy Laboratory, Golden, CO
Jorgensen, GJ
National Renewable Energy Laboratory, Golden, CO
King, DE
National Renewable Energy Laboratory, Golden, CO
Czanderna, AW
National Renewable Energy Laboratory, Golden, CO
Price: $25.00
Contact Sales
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Developed by Committee: G03
Pages: 173–189
DOI: 10.1520/STP16159S
ISBN-EB: 978-0-8031-5342-4
ISBN-13: 978-0-8031-2407-3