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Solar energy harvesting and self‐cleaning of surfaces by an impacting water droplet
Author(s) -
Hassan Ghassan,
Yilbas Bekir S.,
AlSharafi Abdullah,
Sahin Ahmet Z.,
AlQahtani Hussain
Publication year - 2020
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.4935
Subject(s) - wetting , materials science , surface energy , superhydrophobic coating , contact angle , composite material , coating , particle (ecology) , nanotechnology , mechanics , physics , oceanography , geology
Summary The self‐cleaning of surfaces via impacting water droplets is examined pertinent to solar energy applications. The mechanism of spreading and retraction of the impacting droplet onto the dust and cleaned hydrophobic surfaces is considered in the analysis. The spreading factor of the impacting droplet is formulated incorporating the energy balance on the hydrophobic surface. High‐speed photography is used to monitor the impacting droplet behavior. The functionalized silica particles coating is introduced towards generating hydrophobic wetting state on the glass surfaces. Environmental dust particles are characterized prior to self‐cleaning impacting tests. It is found that spreading rate predicted for the impacting droplet agrees well with that obtained from the experiments. The droplet Weber number incorporated in the experiments does not result in droplet breaking on the surface upon impacting. The dusts are dissimilar in shapes and consist of several elements. Impacting droplet gives rise to cloaking of the dust on the surface during spreading and retraction. Almost all the dusts are removed from the surface through the impacting droplets; however, few dust residues are left on the impacting surface, which cover only 0.03% of the total surface area. Hence, we have demonstrated that self‐cleaning of a surface can be achieved by an impacting droplet for renewable energy applications.