Infrared spectral emissivity dynamics of surfaces under water condensation

Water condensation on a surface strongly affects its effective emissivity, especially in the atmospheric window, a wavelength range essential for outdoor applications related to energetically passive cooling and heating. The evolution of emissivity of a silicon surface during dropwise and filmwise w...

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Main Authors: Lavielle, Nicolas, Othman, Ahmed M., Hervé, Armande, Hamaoui, Georges, Fei, Jipeng, Tan, Jun Yan, Marty, Frédéric, Li, Hong, Mongruel, Anne, Beysens, Daniel, Nefzaoui, Elyes, Bourouina, Tarik
Other Authors: School of Mechanical and Aerospace Engineering
Format: Journal Article
Language:English
Published: 2024
Subjects:
Online Access:https://hdl.handle.net/10356/180113
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author Lavielle, Nicolas
Othman, Ahmed M.
Hervé, Armande
Hamaoui, Georges
Fei, Jipeng
Tan, Jun Yan
Marty, Frédéric
Li, Hong
Mongruel, Anne
Beysens, Daniel
Nefzaoui, Elyes
Bourouina, Tarik
author2 School of Mechanical and Aerospace Engineering
author_facet School of Mechanical and Aerospace Engineering
Lavielle, Nicolas
Othman, Ahmed M.
Hervé, Armande
Hamaoui, Georges
Fei, Jipeng
Tan, Jun Yan
Marty, Frédéric
Li, Hong
Mongruel, Anne
Beysens, Daniel
Nefzaoui, Elyes
Bourouina, Tarik
author_sort Lavielle, Nicolas
collection NTU
description Water condensation on a surface strongly affects its effective emissivity, especially in the atmospheric window, a wavelength range essential for outdoor applications related to energetically passive cooling and heating. The evolution of emissivity of a silicon surface during dropwise and filmwise water deposition is studied. The evolution of the spectral radiative properties shows that the increase in effective emissivity due to the growth of a droplet pattern is steeper than for a growing water film of equivalent thickness. The change of surface emissivity takes place in the first moments of condensation where droplets as small as 10 µm drastically impact the reflectance of the pristine surface. The upper limit of effective emissivity is reached for a droplet radius or film thickness of 50 µm. During dropwise condensation, effective emissivity is weighted by the drop surface coverage and then remains within an asymptotic maximum value of 0.8, while in case of filmwise condensation, it is shown to reach 0.9 corresponding to water emissivity. Micrometer-scale spatially-resolved infrared spectral images enable to correlate the spatial variation of spectral properties to the droplet size and localization. Such findings are of interest to the implementation of moisture-controlled emissivity tuning and radiative sky-coolers for dew harvesting.
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spelling ntu-10356/1801132024-09-21T16:48:17Z Infrared spectral emissivity dynamics of surfaces under water condensation Lavielle, Nicolas Othman, Ahmed M. Hervé, Armande Hamaoui, Georges Fei, Jipeng Tan, Jun Yan Marty, Frédéric Li, Hong Mongruel, Anne Beysens, Daniel Nefzaoui, Elyes Bourouina, Tarik School of Mechanical and Aerospace Engineering CINTRA IRL 3288 CNRS-NTU-THALES Engineering Atmospheric water harvesting Atmospheric window Water condensation on a surface strongly affects its effective emissivity, especially in the atmospheric window, a wavelength range essential for outdoor applications related to energetically passive cooling and heating. The evolution of emissivity of a silicon surface during dropwise and filmwise water deposition is studied. The evolution of the spectral radiative properties shows that the increase in effective emissivity due to the growth of a droplet pattern is steeper than for a growing water film of equivalent thickness. The change of surface emissivity takes place in the first moments of condensation where droplets as small as 10 µm drastically impact the reflectance of the pristine surface. The upper limit of effective emissivity is reached for a droplet radius or film thickness of 50 µm. During dropwise condensation, effective emissivity is weighted by the drop surface coverage and then remains within an asymptotic maximum value of 0.8, while in case of filmwise condensation, it is shown to reach 0.9 corresponding to water emissivity. Micrometer-scale spatially-resolved infrared spectral images enable to correlate the spatial variation of spectral properties to the droplet size and localization. Such findings are of interest to the implementation of moisture-controlled emissivity tuning and radiative sky-coolers for dew harvesting. Published version This project was funded by the METAWATER Project (No. ANR-20-CE08-0023 META-WATER) and the BROMEDIR project (No. 101092697). 2024-09-17T07:06:01Z 2024-09-17T07:06:01Z 2024 Journal Article Lavielle, N., Othman, A. M., Hervé, A., Hamaoui, G., Fei, J., Tan, J. Y., Marty, F., Li, H., Mongruel, A., Beysens, D., Nefzaoui, E. & Bourouina, T. (2024). Infrared spectral emissivity dynamics of surfaces under water condensation. Advanced Functional Materials, 34(29), 2403316-. https://dx.doi.org/10.1002/adfm.202403316 1616-301X https://hdl.handle.net/10356/180113 10.1002/adfm.202403316 2-s2.0-85193695716 29 34 2403316 en Advanced Functional Materials © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. application/pdf
spellingShingle Engineering
Atmospheric water harvesting
Atmospheric window
Lavielle, Nicolas
Othman, Ahmed M.
Hervé, Armande
Hamaoui, Georges
Fei, Jipeng
Tan, Jun Yan
Marty, Frédéric
Li, Hong
Mongruel, Anne
Beysens, Daniel
Nefzaoui, Elyes
Bourouina, Tarik
Infrared spectral emissivity dynamics of surfaces under water condensation
title Infrared spectral emissivity dynamics of surfaces under water condensation
title_full Infrared spectral emissivity dynamics of surfaces under water condensation
title_fullStr Infrared spectral emissivity dynamics of surfaces under water condensation
title_full_unstemmed Infrared spectral emissivity dynamics of surfaces under water condensation
title_short Infrared spectral emissivity dynamics of surfaces under water condensation
title_sort infrared spectral emissivity dynamics of surfaces under water condensation
topic Engineering
Atmospheric water harvesting
Atmospheric window
url https://hdl.handle.net/10356/180113
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