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Solar energy is a promising and sustainable natural resource that can be harnessed through solar harvesting devices such as photovoltaic (PV) cells and concentrating solar collectors. The efficiency of these systems can reach up to 23% and 70%, respectively. However, their performance is significantly affected by geographical and environmental factors, such as orientation, inclination angle, longitude, latitude, solar intensity, shade, wind, temperature, and dust accumulation. Among these factors, dust deposition is a major contributor to reduced efficiency, power production, and profitability of solar energy harvesting devices. Accumulated dust can decrease the efficiency of solar systems by more than 70% within a month, depending on their geographical location. The intensity and characteristics of dust, such as shape, size, meteorology, and type, vary worldwide and are determined by the system. Numerous studies have investigated the intensity of dust and various dust cleaning techniques with prospects and challenges to restore the performance of solar energy harvesting systems. This paper focuses on the intensity of dust around the Middle East and North Africa (MENA) region. It provides a detailed review of recent investigations into dust-cleaning techniques for solar energy harvesting systems for researchers, designers, and engineers in this field. Furthermore, it includes a techno-economic comparison of the techniques, which can aid in selecting the most suitable dust-cleaning technique for a particular geographic region based on technical and financial aspects. [ABSTRACT FROM AUTHOR]

• The efficiency of a solar system is highly dependent on the incident solar radiation that reaches the active surfaces. • Optical characteristics of the protective layer of solar panels are crucial for efficient solar energy harvesting. • Dust accumulation (soiling) is one of the most important external factors affecting PV performance and efficiency. • The removal of dust by mechanical cleaning process becomes complicated under strong dust adhesion. • Every cleaning approach has beneficiary features and drawbacks unique to cleaning soiled solar PV panels. This review offers a comprehensive, in-depth analysis of the dust soiling research, including critical observations on dust soiling effects and dust removal techniques for solar energy harvesting applications. The efficiency of a solar energy harvesting system is highly dependent on the incident solar radiation that reaches the active surfaces. Optical characteristics of the protective layer of solar panels, including high transmittance and low absorption, are crucial for efficient solar energy harvesting. Environmental dust reduces the optical transmittance of such surfaces, consequently lowering the device's performance. Therefore, the removal of dust particles becomes critical for efficient energy production. Dust-removal technologies mainly involve natural processes, electrostatic, mechanical, and self-cleaning surface Nano-films. Some of the adopted cleaning techniques require expensive external power, such as pumping/compression, due to the high repelling forces needed to remove such particles. This review evaluates and compares the existing dust removal strategies while focusing on the environmental, technical, and economic perspectives. The findings presented in this study remain crucial toward enlightening the PV scientific world regarding the soiling impact on solar energy harvesting and dust mitigation strategies to maintain high-performance solar PV operations. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In the present study, adhesion of dried mud solution formed on the aluminium surface is investigated and the characteristics of the mud solution are examined using the analytical tools. The adhesion force and the adhesion work required to remove the dried mud solution from the aluminium surface are measured. The findings revealed that the dried mud solution forms crystals with varying sizes on the aluminium surface depending on the mud drying temperature. The dissolution of alkaline and earth alkaline compounds in water is responsible for the formation of crystals on the aluminium surface. The adhesion force and the adhesion work increase significantly as the mud solution drying temperature increases. [ABSTRACT FROM AUTHOR]