Solar radiation durability of materials components and systems for Low Concentration Photovoltaic Systems

Wheeler

et al. 2013

IEEE Access

Self Cite

A better understanding of the degradation modes and rates for photovoltaic (PV) modules is necessary to optimize and extend the lifetime of these modules. Lifetime and degradation science (L&DS) is used to understand degradation modes, mechanisms and rates of materials, components and systems to predict lifetime of PV modules. A PV module lifetime and degradation science (PVM L&DS) model is an essential component to predict lifetime and mitigate degradation of PV modules using reproducible open data science. Previously published accelerated testing data from Underwriter Laboratories on PV modules with fluorinated polyester backsheets, which included eight modules that were exposed up to 4000 hrs of damp heat (85% relative humidity at 85 • C) and eight exposed up to 4000 hrs of ultraviolet light (80 W/m 2 of 280-400 nm wavelengths at 60 • C) (UV preconditioning) were used to determine statistically significant relationships between the applied stresses and measured responses. There were 15 different variables tracking aspects of system performance, degradation mechanisms, component metrics and time. Modules were analyzed for three system performance metrics (fill factor, peak power, and wet insulation). The results were statistically analyzed to identify variable transformations, statistically significant relationships (SSRs) and to develop the PVM L&DS model informed by a generalization of structural equation modeling techniques. The SSRs and significant model coefficients, combined with domain analytics, incorporating materials science, chemistry, and physics expertise, produced a pathway diagram ranking the variables' impact on the system performance, which were iteratively examined using sound statistical analysis and diagnostics. The SSRs determined from the damp heat exposure for the system response of Pmax corresponded to the degradation pathway of polyester terephthalate (PET) and ethylene vinyl acetate (EVA) hydrolysis. A linear change point for the damp heat exposure with the system response of Pmax was determined to be 1890 hrs. The UV preconditioning exposure did not induce sufficient degradation shown by the quality of the R 2 values for many of the best fitting models. This exemplifies the development of a methodology to determine rank ordered lifetime and degradation pathways present in modules and their effects on module performance over lifetime.

Section: Landds Analytics: Resultsmentioning

confidence: 99%

Statistical and Domain Analytics Applied to PV Module Lifetime and Degradation Science

Wheeler

et al. 2013

IEEE Access

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“…For a module surface that is nonnormal to the solar irradiance, (3) gives the dependence of insolation upon a rectangular surface S m for arbitrary solar elevation angle and tilt angle…”

Section: A One-dimensional Geometrical Irradiance Model Developmentmentioning

confidence: 99%

“…An example of a commercial MAPV system supplier is TenK Solar, which provides modules paired with mirrors designed for enhanced light capture and, thus, increased power. In this scenario, the mirrors provide a low-concentration value, and this is referred to as mirror-augmented PV, (MAPV) [3]- [5].…”

Section: Introductionmentioning

confidence: 99%

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Design Considerations and Measured Performance of Nontracked Mirror-Augmented Photovoltaics

Lin

Peshek

et al. 2015

IEEE J. Photovoltaics

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Costs associated with conventional photovoltaic (PV) installations (module manufacturing, mounts, wiring and installation labor, etc.) scale linearly with system area, and prudent design practices for increasing the light harvesting may significantly enhance the power output per unit area and cost per watt. The use of PV modules that have been augmented by the addition of a solar mirror provides an opportunity to improve light harvesting of a PV module and cost-per-watt considerations if the mirror is less expensive than the relative increase in power. In order to harvest greater insolation, an optimized design configuration between a flat-panel module and mirror is necessary for a fixed (nontracked) mirror-augmented photovoltaic (MAPV) system. A series of irradiance and energy harvest calculations were developed to screen various MAPV design configurations. We employed optical raytracing simulations to determine irradiance nonuniformities on the fixed MAPV system. The simulated results are compared with outdoor experimental field trial results. Over a three-month period of study, the fixed MAPV system produced 12% more power than an equivalent nonaugmented panel. An adjustable angle mounting system known as "time machine" was used to estimate yearly power production by adjusting the relative position of the MAPV system to represent varying times of the year. Current-voltage (I-V) curve tracing of test modules was performed during the field trials on augmented and nonaugmented modules for comparison. The experimental time machine result is in agreement with the irradiance simulation, which shows a gullwing curve of annual power output with peak production on the equinoxes and reduced production on the solstices.

“…A recent U.S. Department of Energy workshop on Science for Energy Technologies [1] identified photovoltaics (PV) lifetime and degradation science (L&DS) [2], [3], [4] as a critical scientific challenge for robust adoption of PV. The PVQA Task Force was developed as an international task force to work towards defining what is needed for lifetime qualification standards and tests [5].…”

Section: Introductionmentioning

confidence: 99%

Degradation pathway models for photovoltaics module lifetime performance

Wheeler

2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)

et al. 2013

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Abstract-Previously published accelerated testing data from Underwriter Labs, featuring measurements taken on 18 identical photovoltaic (PV) modules exposed to two stress conditions, were used to develop an analytical methodology. The results provide insight into active degradation mechanisms and pathways present in PV modules under accelerated testing conditions as indicated by statistically significant relationships between variables. Observed experimental results coincide with a domain knowledge based theoretical degradation pathway model informed by literature, and provide a basis for beginning to investigate the degradation modes and pathways truly present in modules and their effects on module performance over lifetime.