Environmental Dust Particles Repelling from A Hydrophobic Surface under Electrostatic Influence

Reduction of Dust on Solar Panels through Unipolar Electrostatic Traveling Wave

In this study, a novel electrostatic cleaning scheme has been applied to a new designed and developed electrode having high cleaning efficiency. In this method, a high voltage, four-channel, 1 Hz square wave signal is applied to a specially designed electrode array. Models of the electric field distribution of the proposed electrode array were developed and analyzed using Ansys Maxwell simulation software and printed circuits boards (PCBs) were produced. The performance of dust removal using the electrodes was evaluated. A 1 MW solar power plant was taken as a case study, and performance and cost were compared with the classical panel cleaning method (wet cleaning system). Our study has shown that the electrostatic cleaning method can be carried out with lower cost and higher efficiency than existing methods.

The Study of Dust Removal Using Electrostatic Cleaning System for Solar Panels

This study explores the use of electrostatic cleaning to remove dust from the surface of photovoltaic solar panels. First of all, existing systems used for dust removal from solar panels were evaluated. Then, the effects of dust on the panel were investigated for Şanlıurfa province in Turkey. In addition, the elemental content of the powder was analyzed. A new device for electrostatic cleaning has been designed and implemented. The cleaning performance of this device has been tested considering the electrode designs. The electric field value was determined by analytical and numerical methods in the conventional model (parallel electrode) model. Electric field distribution was investigated using Ansys Maxwell simulation software. The printed circuit boards of the proposed model and the conventional model were produced. The traditional model with positive and negative waveform is widely used in electrostatic cleaner studies. Dust removal efficiencies and electrical losses for different frequency and voltage values were compared for both cards. It has been shown that the proposed model can perform cleaning with high efficiency despite similar loss variation.

Sliding Water Droplet on Oil Impregnated Surface and Dust Particle Mitigation

Self-cleaning of surfaces becomes challenging for energy harvesting devices because of the requirements of high optical transmittance of device surfaces. Surface texturing towards hydrophobizing can improve the self-cleaning ability of surfaces, yet lowers the optical transmittance. Introducing optical matching fluid, such as silicon oil, over the hydrophobized surface improves the optical transmittance. However, self-cleaning ability, such as dust mitigation, of the oil-impregnated hydrophobic surfaces needs to be investigated. Hence, solution crystallization of the polycarbonate surface towards creating hydrophobic texture is considered and silicon oil impregnation of the crystallized surface is explored for improved optical transmittance and self-cleaning ability. The condition for silicon oil spreading over the solution treated surface is assessed and silicon oil and water infusions on the dust particles are evaluated. The movement of the water droplet over the silicon oil-impregnated sample is examined utilizing the high-speed facility and the tracker program. The effect of oil film thickness and the tilting angle of the surface on the sliding droplet velocity is estimated for two droplet volumes. The mechanism for the dust particle mitigation from the oil film surface by the sliding water droplet is analyzed. The findings reveal that silicon oil impregnation of the crystallized sample surface improves the optical transmittance significantly. The sliding velocity of the water droplet over the thick film (~700 µm) remains higher than that of the small thickness oil film (~50 µm), which is attributed to the large interfacial resistance created between the moving droplet and the oil on the crystallized surface. The environmental dust particles can be mitigated from the oil film surface by the sliding water droplet. The droplet fluid infusion over the dust particle enables to reorient the particle inside the droplet fluid. As the dust particle settles at the trailing edge of the droplet, the sliding velocity decays on the oil-impregnated sample.

Avalanche effect for chemically modified dust mitigation from surfaces

Cost effective dust mitigation from surfaces is one of the challenges in various sectors. The reduction of dust adhesion on surfaces plays a vital role for dust mitigation from surfaces under the gravitational influence. Creating an avalanche effect on dusty surfaces improves the dust mitigation rate and provides an effective cleaning process. Hence, solution treatment of dust by low concentration hydrofluoric acid is considered towards reducing dust adhesion on glass surfaces. To increase the rate of dust mitigation, the avalanche influence is created by the higher density and larger size particles (5300 kg/m3 and ~ 50 µm) than the average size dust particles (2800 kg/m3 and 1.2 µm) via locating them in the top region of the dusty glass surfaces. Mitigation velocity of the dust particles is evaluated using a high-speed recording system and the tracker program. Findings revealed that solution treatment (curing) of the dust particles results in the formation of fluorine compounds, such as CaF2 and MgF2, on dust surfaces, which suppress dust adhesion on surfaces. OSHA Globally Harmonized System lists the fluorine compounds formed as environmentally non-harmful. Avalanche's influence results in dust mitigation at a smaller tilt angle of the glass surface (~ 52°) than that of the case with none-avalanche influence (63°). Area cleaned on the glass surface, via dust mitigation, is larger as the avalanche is introduced, which becomes more apparent for the solution treated dust particles. Dust mitigation under avalanche influence improves optical transmittance of the dusty glass samples by a factor of 98%.

Environmental dust repelling from hydrophilic/hydrophobic surfaces under sonic excitations

Dust repelling from transparent polyvinyl chloride film surface via sonic excitation is examined and dynamics of repelled (inflight) dust particles are analyzed. An experimental rig is designed and built to assess the vibrational characteristics of the polyvinyl chloride film at different frequencies of sonic excitation. A high speed recording system and tracking program are utilized monitoring and evaluating the dynamics of the inflight particles. The dynamics of inflight particles are also simulated numerically and the predictions are compared with those of the experimental data. In order to examine the influence of dust particle adhesion on the dynamics of the inflight particles, the polyvinyl chloride film surface is hydrophobized through dip coating by functionalized nano-silica particles. Improvement of the optical transmittance of the dust mitigated film is determined via outdoor tests. The findings demonstrate that sonic excitation repels the particles from the film surface and it is more pronounced at 64 Hz excitation frequency while demonstrating that sonic excitation can be used for dust removal from transparent surfaces. The mitigation via sonic excitation improves the optical transmittance of the dusty surface by 77%, which becomes more apparent for hydrophobic surfaces.

Droplet Rolling and Spinning in V-Shaped Hydrophobic Surfaces for Environmental Dust Mitigation

The motion of a water droplet in a hydrophobic wedge fixture was examined to assess droplet rolling and spinning for improved dust mitigation from surfaces. A wedge fixture composed of two inclined hydrophobic plates had different wetting states on surfaces. Droplet rolling and spinning velocities were analyzed and findings were compared with the experiments. A wedge fixture was designed and realized using a 3D printing facility and a high speed recording system was adopted to evaluate droplet motion in the wedge fixture. Polycarbonate sheets were used as plates in the fixture, and solution crystallization and functionalized silica particles coating were adopted separately on plate surfaces, which provided different wetting states on each plate surface while generating different droplet pinning forces on each hydrophobic plate surface. This arrangement also gave rise to the spinning of rolling droplets in the wedge fixture. Experiments were extended to include dust mitigation from inclined hydrophobic surfaces while incorporating spinning- and rolling droplet and rolling droplet-only cases. The findings revealed the wedge fixture arrangement resulted in spinning and rolling droplets and spinning velocity became almost 25% of the droplet rolling velocity, which agrees well with both predictions and experiments. Rolling and spinning droplet gave rise to parallel edges droplet paths on dusty hydrophobic surfaces while striations in droplet paths were observed for rolling droplet-only cases. Spinning and rolling droplets mitigated a relatively larger area of dust on inclined hydrophobic surfaces as compared to their counterparts corresponding to rolling droplet-only cases.