scholarly journals Droplet fluid infusion into a dust layer in relation to self-cleaning

RSC Advances ◽  
2020 ◽  
Vol 10 (53) ◽  
pp. 32034-32042
Author(s):  
Ghassan Hassan ◽  
Bekir Sami Yilbas ◽  
Hussain Al-Qahtani
Keyword(s):  
Dust Removal ◽  
Hydrophobic Surfaces ◽  
Dust Layer ◽  
Fluid Infusion ◽  
Self Cleaning ◽  
Droplet Liquid

Wettability of a droplet liquid on a dusty hydrophobic plate is considered and the fluid infusion into the dust layer is studied pertinent to dust removal from the hydrophobic surfaces via rolling/sliding droplets.

Self-Cleaning Solar Mirrors Using Electrodynamic Dust Shield: Prospects and Progress

2014 ◽  
Author(s):  
Malay K. Mazumder ◽  
Mark N. Horenstein ◽  
Jeremy W. Stark ◽  
John N. Hudelson ◽  
Arash Sayyah ◽  
...  
Keyword(s):  
Power Generation ◽  
Particle Size ◽  
High Efficiency ◽  
Solar Collectors ◽  
Parabolic Trough ◽  
Atmospheric Dust ◽  
Efficient Operation ◽  
Dust Layer ◽  
Wide Range ◽  
Self Cleaning

Parabolic trough and power tower technologies provide inherent advantage of thermal energy storage and high efficiency of the Concentrating Solar Power (CSP) systems for utility scale solar plants. High efficiency CSP power generation with minimal water use is one of the SunShot goals of the US Department of Energy. The specular reflectance efficiency of the solar mirrors plays a critical role in the efficiency of power generation. The optical surface of the mirrors and the receiver must be kept clean for efficient operation of the plant. Some environmental challenges in operating the large-scale CSP plants at high reflectance efficiency arise from high concentration of atmospheric dust, wind speed and variation of relative humidity (RH) over a wide range. Deposited dust and other contaminant particles, such as soot, salt, and organic particulate matters attenuate solar radiation by scattering and absorption. Adhesion of these particles on the mirror surface depends strongly by their composition and the moisture content in the atmosphere. Presence of soluble inorganic and organic salts cause corrosion of the mirror unless the contaminants are cleaned frequently. In this paper, we briefly review (1) source of atmospheric dust and mechanisms involved in degradation of mirrors caused by salt particles, (2) loss of specular reflection efficiency as a function of particle size distribution and composition, and (3) an emerging technology for removing dust layer by using thin transparent electrodynamic screen (EDS). Feasibility of integration of EDS on the front surface of the solar collectors has been established to provide active self-cleaning properties for parabolic trough and heliostat reflectors. Prototype EDS-integrated solar collectors including second-surface glass mirrors, metallized acrylic film mirrors, and dielectric mirrors, were produced and tested in an environmental test chambers simulating desert atmospheres. The test results show that frequent removal of dust layer can maintain the specular reflectivity of the mirrors above 90% under dust deposition at a rate ranging from 0 to 10 g/m2, with particle size varying from 1 to 50 μm in diameter. The energy required for removing the dust layer from the solar was less than 10 Wh/m2 per cleaning cycle. EDS based cleaning could therefore be automated and performed as frequently as needed to maintain reflection efficiency above 90% and thus reducing water usage for cleaning mirrors in the solar field. A comparative cost analysis was performed between EDS and deluge water based cleaning that shows the EDS method is commercially viable and would meet water conservation needs.

scholarly journals Stretchable Hydrophobic Surfaces and Self-Cleaning Applications

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Ghassan Hassan ◽  
Hussain Al-Qahtani ◽  
Naser Al-Aqeeli ◽  
Abdullah Al-Sharafi ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Droplet ◽  
Dust Removal ◽  
Dust Particles ◽  
Mass Ratio ◽  
Water Droplets ◽  
Surface Wetting ◽  
Hydrophobic Surfaces ◽  
Removal Mechanisms ◽  
Nano Size

Abstract Hydrophobizing of stretchable elastomer surfaces is considered and the reversible behavior of the resulting surface wetting state is examined after stretching and relaxing the hydrophobized samples. The environmental dust are analyzed in terms of elemental constitutes and size, and the dust pinning on the hydrophobized surface is measured. The dust removal mechanisms, by the water droplets on the hydrophobized surface, are investigated. We demonstrated that deposition of functionalized nano-size silica units on the elastomer surface gives rise to hydrophobicity with 135° ± 3° contact angle and low hysteresis of 3° ± 1°. Stretching hydrophobized elastomer surface by 50% (length) reduces the contact angle to 122° ± 3° and enhances the hysteresis to 6° ± 1°. However, relaxing the stretched sample causes exchanging surface wetting state reversibly. Water droplet rolling and sliding can clean the dusty hydrophobized surface almost 95% (mass ratio of the dust particles removed). Droplet puddling causes striations like structures along the droplet path and close examination of the few residues of the dust reveals that the droplet takes away considerably large amount of dust from surface.

Hydrophobicity of Surfaces Coated with Functionalized Titanium Dioxide Nanoparticles

2016 ◽  
Vol 705 ◽  
pp. 268-272 ◽  
Author(s):  
Paul Albert L. Sino ◽  
Marvin U. Herrera ◽  
Mary Donnabelle L. Balela
Keyword(s):  
Contact Angle ◽  
Silicon Carbide ◽  
Titanium Dioxide ◽  
Titanium Dioxide Nanoparticles ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Water Droplets ◽  
Hydrophobic Surfaces ◽  
Coated Surface ◽  
Self Cleaning

Hydrophobic surfaces are eyed for their self-cleaning ability because water droplets can roll on them (instead of clinging), thus the surface have capability to remove dirt. Hydrophobic surfaces were created by coating functionalized Titanium Dioxide-based paint. The paint was fabricated by reacting fluorosilane molecules in ethanol with titanium dioxide nanoparticles. Ethanol also serves as the volatile suspension medium that evaporates when the paint is coated on surfaces. The paint was coated on different surfaces by simple dipping. Contact angle of coated aluminum sheet, soda-lime glass, filter paper and silicon carbide polishing paper showed hydrophobicity. Water droplets are made to roll on coated soda-lime glass at angle of 0.057°. The ability of water droplets to roll highlights the coated surface self-cleaning potential.

Durable ultra-hydrophobic surfaces for self-cleaning applications

2008 ◽  
pp. n/a-n/a ◽  
Author(s):  
P. F. Rios ◽  
H. Dodiuk ◽  
S. Kenig ◽  
S. McCarthy ◽  
A. Dotan
Keyword(s):  
Hydrophobic Surfaces ◽  
Self Cleaning

Development of Self-Cleaning Solar Collectors for Minimizing Energy Yield Loss Caused by Dust Deposition

2013 ◽  
Author(s):  
Malay Mazumder ◽  
Mark Horenstein ◽  
Jeremy Stark ◽  
Daniel Erickson ◽  
Arash Sayyah ◽  
...  
Keyword(s):  
Large Scale ◽  
Yield Loss ◽  
Research Effort ◽  
Large Fraction ◽  
Dust Removal ◽  
Energy Yield ◽  
Solar Collectors ◽  
Dust Deposition ◽  
Prototype Development ◽  
Self Cleaning

Concentrated Solar Power (CSP) systems used for photothermal conversion of solar energy to electricity are capable of meeting a large fraction of the global energy requirements. CSP plants are inherently robust with respect to the availability of materials, technology, and energy storage. However, dust depositions on solar collectors cause energy yield loss annually, ranging from 10 to 50% depending upon their location in the semi-arid and desert lands. Mitigation of energy loss requires manual cleaning of solar mirrors with water. A brief review of the soiling related losses in energy yield of the CSP plants is presented, which shows that cleaning of the CSP mirrors and receivers using water and detergent is an expensive and time-consuming process at best and is often impractical for large-scale installations where water is scarce. We report here our research effort in developing an electrodynamic dust removal technology that can be used for keeping the solar collectors clean continuously without requiring water and manual labor. Transparent electrodynamic screens (EDS), consisting of rows of transparent parallel electrodes embedded within a transparent dielectric film can be integrated on the front surface of the mirrors and on the receivers for dust removal for their application as self-cleaning solar collectors. When the electrodes are activated, over 90% of the deposited dust is removed. A summary of the current state of prototype development and evaluation of EDS integrated solar mirrors and experimental data on the removal of desert dust samples are presented. A brief analysis of cost-to-benefit ratio of EDS implementation for automated dust removal from large-scale solar collectors is included.

Low Cost Synthesis of Hydrophobic Aluminum Alloy for Self-Cleaning Applications

2015 ◽  
Vol 659 ◽  
pp. 565-569
Author(s):  
Pat Sooksaen ◽  
Paradee Janmat ◽  
Wilaiwan Thovasakul ◽  
Onnuch Chulasinont
Keyword(s):  
Aluminum Alloy ◽  
Aluminium Alloy ◽  
Electrolyte Concentration ◽  
Low Cost ◽  
Electrochemical Anodization ◽  
Hydrophobic Surfaces ◽  
Silane Coating ◽  
Porous Surfaces ◽  
Porous Oxide ◽  
Self Cleaning

This research fabricated hydrophobic surfaces of aluminium alloy via electrochemical anodization and silane coating. The procedures consisted of electrochemical anodization in 1 and 1.5 M sulfuric acid using 12 volts dc. Anodization produced stable porous oxide layer on the surface. Aluminium alloy formed porous oxide structures with thickness in micrometer regime. The thickness of the porous layer was affected by the anodizing conditions such as electrolyte concentration and time. Dichloro methylsilane (5% in ethanol) was applied onto the porous surfaces by submerging the anodized surfaces into it for 10-60 min. After washing the treated surfaces with soap for many times, hydrophobic surfaces were obtained with some surfaces showed wetting angles greater than 100°. Water droplets of any sizes can roll off on these surfaces when tilted at angles above 10°. The treated aluminium surfaces can be applied for self-cleaning and anti-icing applications.

Mechanics of dust removal from rotating disk in relation to self-cleaning applications of PV protective cover

Solar Energy ◽  
2016 ◽  
Vol 130 ◽  
pp. 193-206 ◽  
Author(s):  
Aditia Rifai ◽  
Numan Abu Dheir ◽  
Bekir S. Yilbas ◽  
Mazen Khaled
Keyword(s):  
Rotating Disk ◽  
Dust Removal ◽  
Protective Cover ◽  
Self Cleaning
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