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Title: Degradation in PV Encapsulant Transmittance: Results of the First PVQAT TG5 Study

Abstract

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. The latest versions of the safety and qualification apply ~40 - ~160 days cumulative dose of the AM1.5G total UV radiation. Essential information that might be used to screen encapsulation through product lifetime also 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 higher fidelity, more rigorous UV weathering test. Five representative, known formulations of EVA were studied in addition to one TPU material. Replicate laminated silica/polymer/silica specimens were examined at 10 institutions using a variety of indoor chambers (including Xenon, UVA-340, and high pressure mercury light sources). Specimens were artificially weathered for 180 cumulative days at pre-designated accelerated test conditions. The solar-weighted transmittance, yellowness index, and the UV cut-off wavelength, determined from the measuredmore » hemispherical transmittance, are examined to provide understanding and guidance for the UV light source (lamp type) and temperature used in accelerated UV aging tests.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [1];  [6];  [1];  [7];  [8];  [9];  [10];  [11];  [11];  [9]
  1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
  2. Specialized Technology Resources, Inc. (STR)
  3. The 3M Company
  4. Q-Lab Corporation
  5. National Institute of Standards and Technology (NIST)
  6. Fraunhofer Center for Sustainable Energy Systems (CSE)
  7. Fraunhofer Institute for Solar Energy Systems (ISE)
  8. DuPont Photovoltaic Solutions
  9. Atlas Material Testing Technology L.L.C.
  10. RenewSys India Pvt Ltd.
  11. Suga Test Instruments Co., Ltd.
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1490028
Report Number(s):
NREL/PR-5K00-70366
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Conference
Resource Relation:
Conference: Presented at the Service Life Prediction of Polymeric Materials: Reaching New Heights, 18-24 March 2018, Boulder, Colorado
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; photovoltaics; PV; ultraviolet degradation; decreased performance; product life; UV lamp; reliability; durability; thermal activation

Citation Formats

Miller, David C, Bokria, Jayesh G, Burns, David M, Fowler, Sean, Gu, Xiaohong, Hacke, Peter L, Honeker, Christian C, Kempe, Michael D, Kohl, Michael, Phillips, Nancy H, Scott, Kurt P, Singh, Ashish, Suga, Shigeo, Watanabe, Shin, and Zielnik, Allen F. Degradation in PV Encapsulant Transmittance: Results of the First PVQAT TG5 Study. United States: N. p., 2019. Web.
Miller, David C, Bokria, Jayesh G, Burns, David M, Fowler, Sean, Gu, Xiaohong, Hacke, Peter L, Honeker, Christian C, Kempe, Michael D, Kohl, Michael, Phillips, Nancy H, Scott, Kurt P, Singh, Ashish, Suga, Shigeo, Watanabe, Shin, & Zielnik, Allen F. Degradation in PV Encapsulant Transmittance: Results of the First PVQAT TG5 Study. United States.
Miller, David C, Bokria, Jayesh G, Burns, David M, Fowler, Sean, Gu, Xiaohong, Hacke, Peter L, Honeker, Christian C, Kempe, Michael D, Kohl, Michael, Phillips, Nancy H, Scott, Kurt P, Singh, Ashish, Suga, Shigeo, Watanabe, Shin, and Zielnik, Allen F. Thu . "Degradation in PV Encapsulant Transmittance: Results of the First PVQAT TG5 Study". United States. https://www.osti.gov/servlets/purl/1490028.
@article{osti_1490028,
title = {Degradation in PV Encapsulant Transmittance: Results of the First PVQAT TG5 Study},
author = {Miller, David C and Bokria, Jayesh G and Burns, David M and Fowler, Sean and Gu, Xiaohong and Hacke, Peter L and Honeker, Christian C and Kempe, Michael D and Kohl, Michael and Phillips, Nancy H and Scott, Kurt P and Singh, Ashish and Suga, Shigeo and Watanabe, Shin and Zielnik, Allen F},
abstractNote = {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. The latest versions of the safety and qualification apply ~40 - ~160 days cumulative dose of the AM1.5G total UV radiation. Essential information that might be used to screen encapsulation through product lifetime also 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 higher fidelity, more rigorous UV weathering test. Five representative, known formulations of EVA were studied in addition to one TPU material. Replicate laminated silica/polymer/silica specimens were examined at 10 institutions using a variety of indoor chambers (including Xenon, UVA-340, and high pressure mercury light sources). Specimens were artificially weathered for 180 cumulative days at pre-designated accelerated test conditions. 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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {1}
}

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