Development of an Accelerated Test Design for Predicting the Service Life of the Solar Array at Mead, Nebraska.

Abstract

This report describes an accelerated test which is designed to predict the life of the 25-kW photovoltaic array installed near Mead, Nebraska. Emphasis is placed on the power-output degradation at the module level and on long-term degradation modes, as appropriate for life prediction of mature devices for which infant failures are few. A quantitative model for accelerating testing using multiple environmental stresses is used to develop the test design. The model accounts for the effects of thermal stress by a relation of the Arrhenius form. This relation is then corrected for the effects of nonthermal environmental stresses, such as relative humidity, atmospheric pollutants, and ultraviolet radiation. The correction factors for the nonthermal stresses include temperature-dependent exponents to account for the effects of interactions between thermal and nonthermal stresses on the rate of degradation of power output. A priori quantitative estimates of the model parameters are then used to compute expected degradation rates under various test conditions associated with a complete factorial experimental design. The conditions at the center point of the accelerated test design are selected to cause a loss of 50 percent of the initial power output for the modules over a period of approximately 8 months. The times to failure for other test conditions are then computed and the conditions are adjusted to yield expected failure times between approximately 1 month and 2 years. The resulting model is then used to obtain extrapolated estimates of the expected life of the modules currently operating at Mead, Nebraska. The test conditions, measurements, and data analyses for the accelerated tests are presented for determining the predicted life of the modules in service at Mead. Constant-temperature, cyclic-temperature, and UV types of tests are specified.

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Document Details

Document Type
Technical Report
Publication Date
Jun 07, 1979
Accession Number
ADA306567

Entities

People

  • G. B. Gaines
  • G. T. Noel
  • R. E. Thomas
  • T. S. Shilliday
  • V. E. Wood

Organizations

  • Jet Propulsion Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies
  • Human Systems
  • Sensors

DTIC Thesaurus Topics

  • Antireflection Coatings
  • Coatings
  • Data Analysis
  • Dielectric Gases
  • Electric Fields
  • Energy
  • Environment
  • Fabrication
  • Failure Mode And Effect Analysis
  • Humidity
  • Jet Propulsion
  • Light Sources
  • Materials
  • Power Measurement
  • Solar Panels
  • Test And Evaluation
  • Ultraviolet Radiation

Readers

  • Computational Modeling and Simulation
  • Materials Science and Engineering.
  • Mechanical Engineering/Mechanics of Materials.