eprintid: 3655
rev_number: 9
eprint_status: archive
userid: 73
dir: disk0/00/00/36/55
datestamp: 2017-03-01 11:37:15
lastmod: 2017-03-01 11:38:28
status_changed: 2017-03-01 11:37:15
type: article
metadata_visibility: show
creators_name: Gagliardi, Mariacristina
creators_name: Lenarda, Pietro
creators_name: Paggi, Marco
creators_id: mariacristina.gagliardi@imtlucca.it
creators_id: pietro.lenarda@imtlucca.it
creators_id: marco.paggi@imtlucca.it
title: A reaction-diffusion formulation to simulate EVA polymer degradation in environmental and accelerated ageing conditions
ispublished: pub
subjects: TA
divisions: CSA
full_text_status: restricted
keywords: Degradation; Durability; Reaction-diffusion system; Poly(ethylene-co-vinyl acetate); Photovoltaics; Finite element method
abstract: Among polymers used as encapsulant in photovoltaic (PV) modules, poly(ethylene-co-vinyl acetate), or EVA, is the most widely used, for its low cost and acceptable performances. When exposed to weather conditions, EVA undergoes degradation that affects overall PV performances. Durability prediction of EVA, and thus of the module, is a hot topic in PV process industry. To date, the literature lacks of long-term predictive computational models to study EVA aging. To fill this gap, a computational framework, based on the finite element method, is proposed to simulate chemical reactions and diffusion processes occurring in EVA. The developed computational framework is valid in either case of environmental or accelerated aging. The proposed framework enables the identification of a correspondence between induced degradation in accelerated tests and actual exposure in weathering conditions. The developed tool is useful for the prediction of the spatio-temporal evolution of the chemical species in EVA, affecting its optical properties. The obtained predictions, related to degradation kinetics and discoloration, show a very good correlation with experimental data taken from the literature, confirming the validity of the proposed formulation and computational approach. The framework has the potential to provide quantitative comparisons of degradation resulting from any environmental condition to that gained from accelerated aging tests, also providing a guideline to design new testing protocols tailored for specific climatic zones.
date: 2017
date_type: published
publication: Solar Energy Materials and Solar Cells
volume: 164
publisher: Elsevier
pagerange: 93-106
id_number: 10.1016/j.solmat.2017.02.014
refereed: TRUE
issn: 0927-0248
official_url: http://www.sciencedirect.com/science/article/pii/S0927024817300673
funders: ERC Grant Agreement no. 306622
projects: European Union's Seventh Framework Programme (FP/2007-2013)
citation:   Gagliardi, Mariacristina and Lenarda, Pietro and Paggi, Marco  A reaction-diffusion formulation to simulate EVA polymer degradation in environmental and accelerated ageing conditions.  Solar Energy Materials and Solar Cells, 164.  pp. 93-106.  ISSN 0927-0248      (2017)  
document_url: http://eprints.imtlucca.it/3655/1/1-s2.0-S0927024817300673-main.pdf