A Dual-Transport Model of Moisture Diffusion in PV Encapsulants for Finite-Element Simulations
| Autor: | Marko Topič, Chiara Barretta, Luis F. Castillon, Gernot Oreski, Marko Jankovec, Stefan Mitterhofer |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
vlaga finite element method Flow (psychology) 02 engineering and technology 010402 general chemistry 01 natural sciences moisture Relative humidity Electrical and Electronic Engineering Diffusion (business) udc:621.383.51 Moisture Humidity polymeric materials polimerni materiali Mechanics 021001 nanoscience & nanotechnology Condensed Matter Physics Fick's laws of diffusion Finite element method 0104 chemical sciences Electronic Optical and Magnetic Materials photovoltaics Transient (oscillation) 0210 nano-technology fotovoltaika metoda končnih elementov |
| Zdroj: | IEEE journal of photovoltaics, vol. 10, no. 1, pp. 94-102, 2020. IEEE Journal of Photovoltaics |
| ISSN: | 2156-3403 2156-3381 |
| DOI: | 10.1109/jphotov.2019.2955182 |
| Popis: | A better understanding of moisture ingress in photovoltaic modules is crucial for better predictions of their long-term behavior in the field. Current calculations and simulations of moisture uptake in photovoltaic modules are based on the Fickian diffusion model in a homogeneous material. In this article, in situ humidity measurements in four different encapsulants exposed to transient humidity conditions are compared with Fickian simulations. It is found that the model cannot accurately describe the measured moisture ingress and egress curves. Thus, a new model for finite-element simulations based on two transport mechanisms is applied. The mesh is split into two regions, where channels with a high diffusion coefficient lead through a bulk with a low diffusion coefficient. The diffusion in both regions as well as the flow between them is simulated as Fickian. The new model is able to predict the measured ingress and egress curves more accurately than the Fickian model in all four encapsulants. The same simulation parameters can accurately describe ingress for various relative humidity values between 20% and 80%, as well as egress from 40% to 20%. This allows further prediction of moisture ingress after the measurement of a single ingress curve and a corresponding parameter optimization. However, a nonlinearity of the diffusion during egress at higher moisture values in the encapsulants is found. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|