Degradation in PV Encapsulation Transmittance: An Interlaboratory Study Towards a Climate-Specific Test: Preprint
Reduced optical transmittance of encapsulants resulting from ultraviolet (UV) degradation has frequently been identified as a cause of decreased PV module performance through the life of service in the field. The present module safety and qualification standards, however, apply short UV doses only capable of examining design robustness or 'infant mortality' failures. Essential information that might be used to screen encapsulation through product lifetime remains unknown. For example, the relative efficacy of xenon-arc and UVA-340 fluorescent sources or the typical range of activation energy for degradation is not quantified. We have conducted an interlaboratory experiment to provide the understanding that will be used towards developing a climate- and configuration-specific (UV) weathering test. Five representative, known formulations of EVA were studied in addition to one TPU material. Replicate laminated silica/polymer/silica specimens are being examined at 14 institutions using a variety of indoor chambers (including Xenon, UVA-340, and metal-halide light sources) or field aging. The solar-weighted transmittance, yellowness index, and the UV cut-off wavelength, determined from the measured hemispherical transmittance, are examined to provide understanding and guidance for the UV light source (lamp type) and temperature used in accelerated UV aging tests.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
- Contributing Organization:
- Ecole Polytechnique Federale de Lausanne (EPFL), Neuchatel, Switzerland; Fraunhofer Institute for Solar Energy Systems (ISE), Freiburg, Germany; Specialized Technology Resources, Inc. (STR), Enfield, Connecticut; Case Western Reserve University (CWRU), Cleveland, Ohiol The 3M Company, St. Paul, Minnesota; China National Electric Apparatus Research Institute Co., Ltd. (CEI), Guangzhou, China; Atlas
- OSTI ID:
- 1215096
- Report Number(s):
- NREL/CP-5J00-63508
- Resource Relation:
- Conference: 42nd IEEE Photovoltaic Specialists Conference, 14-19 June 2015, New Orleans, Louisiana
- Country of Publication:
- United States
- Language:
- English
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