Maryam Babaei, Seyed Gholamreza Etemad, Masoud Haghshenasfard, Boguslaw Kruczek, Eliana Jara Morante, Jules Thibault

Abstract: Collecting water from atmospheric air by condensation on a passive surface cooled by radiation to a clear night sky was studied as a function of the geometry and emissivity of the condensing surface, wind speed, air relative humidity, and air temperature using two-dimensional CFD simulations. Results show that an increase in the wind speed leads to an increase in the plate temperature, resulting in a decrease in the driving force for condensation. On the other hand, the mass transfer coefficient for the transport of water vapour from the bulk air stream to the plate increases with the wind speed. The latter effect is stronger than the former one, such that for wind speeds for which the plate remains below the dew point temperature, the condensation rate increases with the wind speed. The effects of the relative humidity and the ambient air temperature were also examined to determine how they impact the ability of passive collectors to condense water.

Keywords: Sky temperature, Vapour condensation, Water collection, Relative humidity, Plate temperature, Plate emissivity

Date Published: March 11, 2020
DOI: 10.11159/jffhmt.2020.002

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