Overview of Factors Affecting Dust Deposition on Photovoltaic Cells and Cleaning Methods

Dust deposition on the surface of photovoltaic (PV) cells poses a significant challenge to their efficiency, especially in arid regions characterized by desert and semi-desert conditions. Despite the pronounced impact of dust accumulation, these regions offer optimal solar radiation and minimal cloud cover, making them ideal candidates for widespread PV cell deployment. Various surface cleaning methods exist, each employing distinct approaches. Choosing an appropriate cleaning method requires a comprehensive understanding of the mechanisms involved in both dust deposition on module surfaces and dust adhesion to PV cell surfaces. The mechanisms governing dust deposition and adhesion are complex and multifaceted, influenced by factors such as the nature and properties of the dust particles, environmental climatic conditions, characteristics of protective coatings, and the specific location of the PV installation. These factors exhibit regional variations, necessitating the implementation of diverse cleaning approaches tailored to the unique conditions of each location. The first part of this article explores the factors influencing dust deposition on PV cell surfaces, delving into the intricate interplay of environmental variables and particle characteristics. Subsequently, the second part addresses various cleaning methods, offering an analysis of their respective advantages and disadvantages. By comprehensively examining the factors influencing dust accumulation and evaluating the effectiveness of different cleaning strategies, this article aims to contribute valuable insights to the ongoing efforts to optimize the performance and longevity of photovoltaic systems in diverse geographical contexts.

Design and Numerical Simulation of Dust Removal System for Sutomotive Iongitudinal Beam Plasma Cutting

To improve the poor efficiency of the dust removal system in the plasma cutting station of automotive longitudinal beams,and reduce the cutting surface quality degradation due to dust,a bottom-side suction dust removal system is designed,and the dust removal effect is optimized through the setting of the following dampers and diversion plates.The result of numerical simulation indicates that the particle collection rate can reach 99.44%,and the field test also proves the effectiveness of the dust removal system,which is of guiding significance for the transformation of other similar dust removal systems.

Low-Cost Automated PV Panel Dust Cleaning System for Rural Communities

Dust accumulation on photovoltaic (PV) panels degrades PV panels’ performance;leading to decreased power output and consequently high cost per generated kilowatt. Research addressing the severity of dust accumulation on PV panels has been ongoing since the 1940s, but proposed solutions have tended to increase the cost of PV systems either from oversizing or from cleaning the system. The objective of this work, therefore, is to design and implement a low-cost affordable automated PV panel dust cleaning system for use in rural communities of Sub-Saharan Africa (SSA);where financial resources are limited and significantly strained in meeting livelihood activities. Complete design and implementation details of a prototype system are provided for easy replication and capitalization on PV systems for sustainable energy needs. The system detects dust based on the innovative use of light-dependent resistors. Testing and observation of the system in operational mode reveal satisfactory performance;measured parameters quantify a power output increase of 33.76% as a result of cleaning dust off the PV panel used in the study.

Spatial and temporal gradients in the rate of dust deposition and aerosol optical thickness in southwestern Iran

The southwestern Iran is one of the regions that are most prone to dust events.The objective of this study is the analysis of the spatial and temporal distributions of dust deposition rate as a key factor for finding the relative impact of the dust.First,the monthly mean aerosol optical thickness(AOT)from Moderate Resolution Imaging Spectroradiometer(MODIS)was analyzed and compared with the dust amount variations from ground deposition rate(GDR),and the results were further used to investigate the spatial and temporal distributions of dust events in southwestern Iran for the period between 2014 and 2015.Moving air mass trajectories,using the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,were proven to be a discriminator of their local and regional origin.The results from GDR analysis produced a correlation coefficient between dust event history and deposition rates at dust magnitudes of>0.93 that is meaningful at the 95%confidence level.Furthermore,the deposition rates varied from 3 g/m2 per month in summer to 10 g/m2 per month in spring and gave insight into the transport direction of the dust.Within the same time series,AOT correspondences with MODIS on Terra in four aerosol thickness layers(clean,thin,thick,and strong thick)were shown in relation to each other.The deepest mixed layers were observed in spring and summer with a thickness of approximately 3500 m above ground level in the study area.Investigations of ground-based observations were correlated with the same variations for each aerosol thickness layer from MODIS images and they can be applied to discriminate layers of aeolian dust from layers of other aerosols.Together,dust distribution plots from AOT participated to enhance mass calculations and estimation deposition rates from the thick and strong thick aerosol thickness layers using the results from GDR.Despite all the advances of AOT,under certain circumstances,ground-based observations are better able to represent aerosol conditions over the study area,which were tested in southwestern Iran,even though the low number of observations is a commonly acknowledged drawback of GDR.

Combined Removal of Surface Moisture and Dust from Feed Coal for Coal Dry Cleaning with an Air-solid Fluidized Bed

A demonstration plant and a commercial plant employing coal dry cleaning technology with an air-solid fluidized bed were built in China. The operation practice of these two plants shows that the surface moisture and the fines or dust of feed coal must be well controlled as low as possible. For this purpose, a new process of combined removal of surface moisture and dust from feed coal using a vibrated fluidized bed dryer was investigated in a batch test apparatus and a pilot test system. A mathematical model on drying kinetics of coal surface moisture was developed and three empirical formulas of the model coefficient involving the main operating variables were determined based on the test results from the batch test apparatus. The mathematical model shows that the surface moisture retained in coal during drying decreases exponentially with drying time. According to this model, a new divisional heat supply mode, in which the inlet gas of higher temperature was introduced into the fore part of the dryer and the inlet gas of lower temperature into the rear part of the dryer, was employed in the pilot test system. The pilot tests show that 1） the new divisional heat supply mode is effective for lowering down the average temperature and reducing the total heat loss of the outlet gas off the dryer, 2） the moist coal of about 60 g/kg surface moisture contentcan be dried to about 10 g/kg, and simultaneously the fines （〈1mm in diameter） adhering to the surface of coarse coal particles are completely washed off by the gas flow.

Image Analysis on Detachment Process of Dust Cake on Ceramic Candle Filter

Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.

Aerosol Filtration Application Using Fibrous Media—An Industrial Perspective

Filtration of aerosol particles using non-woven fibrous media is a common practice for air cleaning. It has found wide applications in industries and our daily lives. This paper overviews some of these applications and provides an industrial perspective. It starts from discussing aerosol filtration theory, followed by a brief review on the advancement of filtration media. After that, filtration applications in respiratory protection, dust collection, and engine in-take air cleaning are elaborated. These are the areas that the author sees as the typical needed ones in China's fast pace economical development endeavor, where air filtration enables the protection of human health, environment and equipment for sustainability.

Main Characteristics of Dust Storms and Their Radiative Impacts: With a Focus on Tajikistan

known aridity of the region is a major factor in promoting numerous dust storms. They have many diverse impacts on the environment and the climate of the region. The classification of dust storms and synoptic conditions related to their formation in Central Asia are discussed in the content of their diverse impact. We address dust optical properties that are representative of the region. Dust storms significantly reduce visibly and pose a human health threads. They also cause a significant impact on the radiative regime. As a result, dust storms may cause a decrease in temperature during daytime of up to 16℃ and an increase in temperature during night time from up to 7℃ compared to a clear day.

Experimental and modeling study on dust cake profile and its influence on pressure drop in fiber filter

Alumina （MMAD： 32.45μm） was used to study dust cake formation in fiber filter at steady-state operation. Cake vertical profile along filter medium versus filtration velocity （ranging from 3 to 7cm/s）, particle concentration （ranging from 40 to 120g/m^3） and particle areal mass to filter （ranging from 0.57 to 2.86 kg/m^2）, was researched by experiments and modeling. The filtration was carried through by a plane filter media （Material： Terylene felt, Thickness： 1.8mm） covered on a framework which was fixed in a filter. During filtration, the cake thickness was measured up and down by a mobile microscope and a camera controlled by a PC. The results showed that the cake vertical profile accord with a peak function. The peak amplitude A, center displacement xc, the shape parameters W of the peak function was greatly depended on filtration velocity and particle areal mass to filter, whereas slightly on particle concentration. The relationships between the three coefficients （peak amplitude A, center displacement xc, the shape parameters W） and filtration velocity, areal mass to filter, particle concentration were associated as equations, based on which pressure drop model was deduced. The peak function and pressure drop model were verified with experimental data.

Simulation and Evaluation of Dust Emission with Polair3D-SIREAM Model over West Africa Focused on Ouagadougou (Burkina Faso)

The study of air pollution is recent in West Africa. There is a lack of data on air pollution. However, some studies conducted in West Africa show that air quality is a concern. Population growth and massive vehicles imports are contributing to the deterioration of this air quality. In this work, we present the modelling of desert aerosols using a CTM Polair3D-SIREAM. The objective is to evaluate the ability of Polair3D-SIREAM to reproduce observations of PM10 and Aerosol Optical Thicknesses (AOT). A simulation with Polair3D-SIREAM was carried out in West Africa, focused on Ouagadougou (Burkina Faso) for 2007. The model of Marticorena and Bergametti (1995), MB95, was used to estimate desert aerosols emissions. The total emission of dust modelled is 52.2 Tg. For the evaluation of PM10, the simulated averages remained within the same orders of magnitude as the observed averages. Correlations are low in all the observation sites. The other indicators are similar to those found by Schmechtig et al. (2011). Performance criteria of Boylan and Russel (2006) are met for the observation sites of Ouagadougou and Ilorin (Nigeria). For the AOTs, the correlations are significantly improved, in particular, at the sites of Ouagadougou and Ilorin. Performance criteria of Boylan are met for all observation sites. However, the performance goals are only achieved for Ouagadougou and Ilorin.

The contribution of small leaks in a baghouse filter to dust emission in the PM2.s range-A system approach

The contribution of leakage in a baghouse filter （defined as a short circuit between the upstream and downstream sides of the filter） to the emission of fine particles is quantified in comparison to other dust emission sources, and the influence of key operating variables on overall system response is analyzed. The study was conducted on a well-maintained pilot-scale filter unit （9 bags of 500 g/m^2 calendered polyester needle felt; total surface area 4.2 m^2） operated in Ap-controlled mode over a range of pulsing intensities, with two types of test dust （one free-flowing and the other cohesive） at inlet concentrations of 10 and 30 g/m^3. Leaks included single holes between 0.5 and 4 mm diameter, intentionally placed in either the plenum plate or one of the filter bags, as well as seamlines from bag confectioning. Emissions were sep- arated by source into a transient contribution due to dust penetration through the filter bags after each cleaning pulse, and a continuous contribution from leaks. This separation was based on a novel method of data processing that relies on time-resolved concentration measurements with a specially calibrated optical particle counter. Tiny leaks on the order of 1 mm generated the same emission level as all the bags combined, and dominated continuous emissions. The equivalent leak cross section （leakage = media emission） was about 1 ppm of the total installed filter surface, independent of upstream dust concentra- tion. Leakage through open seamlines amounted to 75% of media emissions in case of free-flowing test dust. Leakage was restricted to aerodynamic diameters less than ~5 μm （roughly the PM2.s mass frac- tion）. For comparison, time-averaged mass penetration through conventional needle-felt media ranged from about 10^-5 to 10^-6, depending on cohesiveness of the particle material and pulse cleaning intensity, giving emission levels between about 0.02 and 0.2 mg/m^3 at the reference concentration of 10 R/m^2.

Forecasting of Asian dust storm that occurred on May 10-13, 2011, using an ensemble-based data assimilation system

An ensemble-based assimilation system that used the MASINGAR ink-2 （Model of Aerosol Species IN the Global AtmospheRe Mark 2） dust forecasting model and satellite-derived aerosol optical thickness （AOT） data. processed in the JAXA （Japan Aerospace Exploration Agency） Satellite Monitoring for Environmental Studies （JASMES） system with MODIS （Moderate Resolution Imaging Spectroradiometer） observations. was used to quantify the impact of assimilation on forecasts of a severe Asian dust storm during May 10-13. 2011. The modeled bidirectional reflectance function and observed vegetation index employed in JASMES enable AOT retrievals in areas of high surface reflectance, making JASMES effective for dust forecasting and early warning by enabling assimilations in dust storm source regions. Forecasts both with and without assimilation were validated using PM^0 observations from China, Korea, and Japan in the TEMM WG1 dataset. Only the forecast with assimilation successfully captured the contrast between the core and tail of the dust storm by increasing the AOT around the core by 70-150% and decreasing it around the tail by 20-30% in the 18-h forecast. The forecast with assimilation improved the agreement with observed PMlo concentrations, but the effect was limited at downwind sites in Korea and Japan because of the lack of observational constraints for a mis-forecasted dust storm due to cloud.

连通设备粉尘爆炸泄压面积确定方法

国内外相关标准提供了单体设备的泄压面积计算方法,但连通设备的准则尚属空白.通过FLACS数值模拟,以玉米淀粉为爆炸介质,探究了连通设备内的泄爆压力和压力上升速率.结果表明:当管道长度一定时,传爆容器内最大泄爆压力随泄压面积增加而降低;在设置相同泄压面积时,传爆容器内的最大泄爆压力随管道长度的增长而增大,且达到最大泄爆压力的时间也随之延后;传爆容器所需最小安全泄压面积大于同等大小单体设备的泄压面积,说明现有单体设备的泄压面积计算方法对于连通设备不适用.通过数值拟合,对标准中单体设备的泄压面积计算公式进行修正,使其满足连通设备安全泄压要求.研究结果为连通系统的防爆设计提供参考和依据.

特大型硫磺储运系统粉尘防控技术应用总结

普光天然气净化厂设计硫磺产能2.4 Mt/a,是亚洲最大的硫磺生产基地。针对该厂特大型硫磺储运系统存在的皮带输送单元落地硫磺粉尘扩散、地下廊道硫磺粉尘超标、装车单元粉尘闪爆等安全隐患,围绕固体硫磺仓储、输送、装车环节开展粉尘风险防控难题攻关,研究皮带机集成清扫、地下廊道粉尘消减及粉尘闪爆综合治理技术,形成了特大型固体硫磺储运系统全流程粉尘防控关键技术,实现了安全清洁生产,提高了装置本质安全水平。

卧式三角型滤筒的脉冲喷吹清灰性能

【目的】为优化卧式三角型滤筒除尘器的清灰性能,探究不同喷吹气流对滤筒内部压力分布的影响,获得不同喷吹孔型式对三角型滤筒的清灰性能的影响规律。【方法】分别采用直管喷吹孔、文氏里管、散射喷嘴、新型曲面诱导引射器共4种喷吹孔型式的诱导引流装置对卧式三角型滤筒开展冷态脉冲实验,以侧壁压强峰值和相对标准偏差作为评价清灰性能的技术指标,分别探讨不同条件下的喷吹射流对滤筒内壁压力分布的影响。【结果】在喷吹压强分别设为0.3、0.4、0.5 MPa的条件下,采用直管、文丘里管、新型曲面诱导引射器时喷吹距离分别设为150、200、250、300、350、400 mm,采用散射喷嘴时喷吹距离分别设为25、50、75、100、125、150、175 mm,则采用直管、文丘里管、散射喷嘴、新型曲面诱导引射器时的平均侧壁压强峰值分别为1037、1758、952、1533 Pa,相对标准偏差分别为0.76、0.58、0.09、0.16;采用新型曲面诱导引射器喷吹孔时,比采用散射喷嘴时的清灰强度高61%,比采用文丘里管时的相对标准偏差小0.47。【结论】新型曲面诱导引射器同时兼顾对侧壁压强峰值和相对标准偏差的要求,在4种喷吹孔型式中清灰性能最佳。

吹吸式除尘装置清除极片表面粉末

为提高锂离子电池安全性能与质量,设计基于高频气流的吹吸式除尘装置。以锂离子电池负极片、微米级铜粉为研究对象,与风刀和吸罩的除尘效果进行对比。当极片运行速度为0.3 m/s时,随着吹吸式除尘装置工作距离由2 mm增加到10 mm,粉尘去除率由97.04%下降至71.88%;当工作距离为2 mm时,随着极片运行速度由0.1 m/s增加至0.5 m/s,粉尘去除率由97.96%降低至95.29%。随着吹吸式除尘装置工作正压增大,除尘性能提高,工作正压为14 kPa时,在极片表面粉尘去除率达99.27%。与风刀和吸罩相比,吹吸式除尘装置能在较低的功耗下实现更高的粉尘去除率。

海岛应急保障设备防潮防尘防盐雾一体化微环境控制技术及性能验证

目的 研发防潮防尘防盐雾一体化微环境控制技术与过滤设备,为延长海岛应急保障设备寿命提供技术支撑。方法 通过对比过滤器入口与出口湿度的变化情况,评估其防潮性。在试验棚下测试开启和未开启过滤设备过程中灰尘浓度的变化情况,测试其防尘性。利用吸气法采集过滤器前后端盐雾浓度,对比其过滤效率。利用高精度铜腐蚀片还原法,表征过滤前后盐雾浓度对腐蚀性的影响情况。结果 采用防潮防尘防盐雾一体化控制技术后,相对湿度由94%降至72%,粉尘质量浓度降低至3μg/m~3以下,环境腐蚀等级由G2降至G1,盐雾浓度水平由Sc3降至Sc1。结论 防潮防尘防盐雾一体过滤技术具有良好的防潮、防尘以及防盐雾效果,可为海洋服役环境下的应急保障设备优化使用环境,保障其安全运行。

洗煤厂破碎筛分除尘系统升级改造可行性研究

为了优化厂区工作环境,实现全面清洁生产的目标,针对山西某洗煤厂破碎筛分工序的扬尘问题,通过分析现有设备运行现状,结合行业标准及设计规范要求,得到了符合现场实际生产情况的除尘系统升级改造方案,并对方案进行系统性验算,以确保方案的合理性,既提高了工人工作环境质量,又降低了矿粉以扬尘的形式流失,实现厂区的达标排放要求,具有良好的社会效益。

Solar Panels Cleaning Frequency for Maximum Financial Profit

Allowing the dust to accumulate on solar panels without adequate cleaning leads to huge monetary losses. Proper judgment of when to call for washing of solar panels is a compromise between gross costs of cleaning the panels and how much reduction in efficiency of solar panels can be tolerated. In this paper, we derive a formula for the optimal number of days between cleaning cycles of a solar array by minimizing the cost of cleaning the array and the lost revenue from the unclean panels. The formula will aid in deciding cleaning periods based on the environment in which the solar panels are installed and cost incurred from undertaking the washing process.

An Experimental and Numerical Study on the Cleaning of Pleated Bag Filters Using Low-Pressure Pulsed-Jets

Pulsed-jet cleaning is recognized as the most efficient method to regenerate bag dust collectors traditionally used in industrial processes to control the emission of particulates.In this study,non-woven needle felt filter bags with and without a film coating material have been analyzed considering different geometries(different number N of pairs of pleated filter bag sides)in the frame of dedicated low-pressure pulsed-jet cleaning experiments.The flow structure inside the bag and the response characteristics of its wall have also been analyzed numerically through a computational fluid-dynamics/structural-dynamics(CFD-CSD)unidirectional fluid-solid coupling method.As shown by the experiments,the peak pressure(P_(0))on the wall of the filter bag with N=8 and 12 is higher,which indicates dust can be removed more effectively in these cases.The peak pressure on the wall increases first and then decreases along the direction of the bag length,while the peak pressure of the pleated filter bag with nonwoven needled felt film coating is greater than that without film coating.A comprehensive analysis of the time variation of acceleration,deformation,strain,stress and other factors,has led to the conclusion that the pleated filter bag with N=12 would be the optimal choice.