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Title: Soiling and cleaning: Initial observations from 5-year photovoltaic glass coating durability study

Abstract

The contamination of solar photovoltaic cover glass can significantly reduce the transmittance of light to the surface of the photovoltaic cell, reducing the module's power output. The solar industry has been developing antireflection (AR) and antisoiling (AS) surface coatings to enhance light transmittance and mitigate the impacts of soiling. Although uncoated glass has been field tested for decades, minimal data exist to demonstrate the durability of AR and AS coatings against abrasion and surface erosion, including from: natural weathering, airborne sand, and industry cleaning practices. Coupons 75 mm square of varying types have been field-deployed to gather long-term data on coating durability; the initial results are presented here after 1 year of outdoor exposure near Sacramento, California. Duplicate sets of coupons were cleaned monthly per four different cleaning practices. All coupons demonstrated inorganic soiling as well as microscale biological contamination, regardless of cleaning method. Additionally, full-sized, field-aged modules from other areas of the world presented with similar types of contamination as the field-aged coupons; micrographs and results from genomic sequencing of this contamination are included here. Optical microscopy, scanning electron microscopy, atomic force microscopy/energy-dispersive spectroscopy, surface roughness, transmittance, and surface energy analysis of representative specimens and cleaning practices are presented.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
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:
1458821
Report Number(s):
NREL/JA-5J00-71853
Journal ID: ISSN 0927-0248
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Solar Energy Materials and Solar Cells
Additional Journal Information:
Journal Volume: 185; Journal Issue: C; Journal ID: ISSN 0927-0248
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 47 OTHER INSTRUMENTATION; coatings; durability; fungi; optical performance; particulate matter; soiling

Citation Formats

Toth, Sarah, Muller, Matthew, Miller, David C., Moutinho, Helio, To, Bobby, Micheli, Leonardo, Linger, Jeffrey, Engtrakul, Chaiwat, Einhorn, Asher, and Simpson, Lin. Soiling and cleaning: Initial observations from 5-year photovoltaic glass coating durability study. United States: N. p., 2018. Web. doi:10.1016/j.solmat.2018.05.039.
Toth, Sarah, Muller, Matthew, Miller, David C., Moutinho, Helio, To, Bobby, Micheli, Leonardo, Linger, Jeffrey, Engtrakul, Chaiwat, Einhorn, Asher, & Simpson, Lin. Soiling and cleaning: Initial observations from 5-year photovoltaic glass coating durability study. United States. doi:10.1016/j.solmat.2018.05.039.
Toth, Sarah, Muller, Matthew, Miller, David C., Moutinho, Helio, To, Bobby, Micheli, Leonardo, Linger, Jeffrey, Engtrakul, Chaiwat, Einhorn, Asher, and Simpson, Lin. Thu . "Soiling and cleaning: Initial observations from 5-year photovoltaic glass coating durability study". United States. doi:10.1016/j.solmat.2018.05.039. https://www.osti.gov/servlets/purl/1458821.
@article{osti_1458821,
title = {Soiling and cleaning: Initial observations from 5-year photovoltaic glass coating durability study},
author = {Toth, Sarah and Muller, Matthew and Miller, David C. and Moutinho, Helio and To, Bobby and Micheli, Leonardo and Linger, Jeffrey and Engtrakul, Chaiwat and Einhorn, Asher and Simpson, Lin},
abstractNote = {The contamination of solar photovoltaic cover glass can significantly reduce the transmittance of light to the surface of the photovoltaic cell, reducing the module's power output. The solar industry has been developing antireflection (AR) and antisoiling (AS) surface coatings to enhance light transmittance and mitigate the impacts of soiling. Although uncoated glass has been field tested for decades, minimal data exist to demonstrate the durability of AR and AS coatings against abrasion and surface erosion, including from: natural weathering, airborne sand, and industry cleaning practices. Coupons 75 mm square of varying types have been field-deployed to gather long-term data on coating durability; the initial results are presented here after 1 year of outdoor exposure near Sacramento, California. Duplicate sets of coupons were cleaned monthly per four different cleaning practices. All coupons demonstrated inorganic soiling as well as microscale biological contamination, regardless of cleaning method. Additionally, full-sized, field-aged modules from other areas of the world presented with similar types of contamination as the field-aged coupons; micrographs and results from genomic sequencing of this contamination are included here. Optical microscopy, scanning electron microscopy, atomic force microscopy/energy-dispersive spectroscopy, surface roughness, transmittance, and surface energy analysis of representative specimens and cleaning practices are presented.},
doi = {10.1016/j.solmat.2018.05.039},
journal = {Solar Energy Materials and Solar Cells},
issn = {0927-0248},
number = C,
volume = 185,
place = {United States},
year = {2018},
month = {6}
}

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