Thomas, Tibin M;
Sinha Mahapatra, Pallab;
Ganguly, Ranjan;
Tiwari, Manish K;
(2023)
Preferred Mode of Atmospheric Water Vapor Condensation on Nanoengineered Surfaces: Dropwise or Filmwise?
Langmuir
10.1021/acs.langmuir.3c00022.
(In press).
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Abstract
Condensing atmospheric water vapor on surfaces is a sustainable approach to addressing the potable water crisis. However, despite extensive research, a key question remains: what is the optimal combination of the mode and mechanism of condensation as well as the surface wettability for the best possible water harvesting efficacy? Here, we show how various modes of condensation fare differently in a humid air environment. During condensation from humid air, it is important to note that the thermal resistance across the condensate is nondominant, and the energy transfer is controlled by vapor diffusion across the boundary layer and condensate drainage from the condenser surface. This implies that, unlike condensation from pure steam, filmwise condensation from humid air would exhibit the highest water collection efficiency on superhydrophilic surfaces. To demonstrate this, we measured the condensation rates on different sets of superhydrophilic and superhydrophobic surfaces that were cooled below the dew points using a Peltier cooler. Experiments were performed over a wide range of degrees of subcooling (10–26 °C) and humidity-ratio differences (5–45 g/kg of dry air). Depending upon the thermodynamic parameters, the condensation rate is found to be 57–333% higher on the superhydrophilic surfaces compared to the superhydrophobic ones. The findings of the study dispel ambiguity about the preferred mode of vapor condensation from humid air on wettability-engineered surfaces and lead to the design of efficient atmospheric water harvesting systems.
| Type: | Article |
|---|---|
| Title: | Preferred Mode of Atmospheric Water Vapor Condensation on Nanoengineered Surfaces: Dropwise or Filmwise? |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1021/acs.langmuir.3c00022 |
| Publisher version: | https://doi.org/10.1021/acs.langmuir.3c00022 |
| Language: | English |
| Additional information: | © 2023 The Authors. Published by American Chemical Society. Original content in this paper is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Aluminum, Atmospheric chemistry, Condensation, Copper, Humidity |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10167821 |
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