TY - GEN
T1 - Degradation in PV Encapsulation Transmittance: An Interlaboratory Study Toward a Climate-Specific Test
T2 - NREL (National Renewable Energy Laboratory)
AU - Miller, David
AU - Hacke, Peter
AU - Kempe, Michael
AU - Annigoni, Eleonora
AU - Ballion, Amal
AU - Bokria, Jayesh
AU - Bruckman, Laura
AU - Burns, David
AU - Elliott, Lamont
AU - French, Roger
AU - Fowler, Sean
AU - Gu, Xiaohong
AU - Honeker, Christian
AU - Khonkar, Hussam
AU - Köhl, Michael
AU - Perret-Aebi, Laure-Emmanuelle
AU - Phillips, Nancy
AU - Scott, Kurt
AU - Sculati-Meillaud, Fanny
AU - Shioda, Tsuyoshi
AU - Suga, Shigeo
AU - Watanabe, Shin
AU - Chen, Xinxin
AU - Feng, Jiangtao
PY - 2015
Y1 - 2015
N2 - Reduced optical transmittance of encapsulation resulting from ultraviolet (UV) degradation has frequently been identified as a cause of decreased PV module performance through the life of installations 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 Xe, 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. Index Terms -- reliability, durability, thermal activation.
AB - Reduced optical transmittance of encapsulation resulting from ultraviolet (UV) degradation has frequently been identified as a cause of decreased PV module performance through the life of installations 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 Xe, 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. Index Terms -- reliability, durability, thermal activation.
KW - durability
KW - reliability
KW - thermal activation
M3 - Presentation
T3 - Presented at the 42nd IEEE Photovoltaic Specialists Conference, 14-19 June 2015, New Orleans, Louisiana
ER -