ppt on dust

8/12/2019 ppt on dust

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Presented By: Manu Sharma


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The performance of a solar energy system(whether using thermal or PV collector) isinfluenced by the ability of the cover glass totransmit solar radiation to the collection surface.

It may be concluded that the effect of dust on theperformance of PV cells can no longer becorrelated to the exposure time in a given site assuggested by many researchers.

The results also indicate that the nature of the dust,such as dust material, its size distribution and thedust deposition density, has a strong influence onthe loss of output power from the PV panels.


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Salim et al. [1] constructed a PV test system at asolar village near Riyadh, Saudi Arabia, tostudy the effect of long term accumulation of

dust on the PV array energy output. With thefixed tilted array at 24.6, the monthly energyreduction for the unclean array was obtainedby comparing its performance with an identical

array, which was cleaned daily. The reductionin the energy output from the unclean arrayreached 32% at the end of eight months.


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Just like grime on a household window, thatdust reduces the amount of light that can enterthe business part of the solar panel, decreasing

the amount of electricity produced. Clean water tends to be scarce in these areas,

making it expensive to clean the solar panels.

It is reported that a dust layer of 4 gram persquare meter decreases solar power conversionby 40 percent.


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The self-cleaning technology for solar cell arraycan promote efficiency of electricity producedand protect the solar cell.

The methods of dust-removal, such as natural means

mechanical means

self-cleaning nano-film

electrostatic means


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The natural powers are employed to removethe dusts, such as wind power, gravitation andthe scour of the rainwater. The effect of this

method is not very well. It is viable that the solar cell array can be

turned to vertical or oblique position to removethe dusts easily when early morning, late

evening, night and a rainy day.

However, the rotation of the large solar cellarray is very difficult


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The mechanical methods remove the dusts by

Brushing.

Blowing.

Vibrating. Ultrasonic driving.

The brushing methods clean the solar cell withsomething like the broom or brush that weredriven by the machine was designed just likewindscreen-wiper.


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The blowing method cleaning the solar cell

with wind power is an effective cleaning oneexcept the low efficiency, high energy-consumption and the unsatisfactorymaintainability of the blower.

Removing the dusts with vibrating andultrasonic is also a valid mechanical cleaningmethod. The key of this strategy consist of thedriving method, the frequency and theamplitude of the solar cell.


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If the surfaces of the solar cell array were covered with

a pellucid self-cleaning nano-film, it will keep clean.The self-cleaning nano-film is made of superhydrophilicity material or super-hydrophobic material.

Super hydrophilicity film:

The popular super hydrophilicity film is TiO2, which hashydrophilicity and photocatalytic activity.

The self-cleaning method consists of two stages. The first one is photocatalytic process which TiO2 film reacts

under the ultraviolet light, and split the organics dirt. Then, because of the hydrophilicity, the rainwater will diffuse

to the whole surface instead of get together and rinse the dust.

This self-cleaning method can not be used in solar cellarray because they worked mostly in desert region

with seldom rain.


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Super-hydrophobic film

Super hydrophobic surfaces such as the leaves ofthe lotus plant show high hydrophobicity and

extremely low wettability. Various studies havebeen conducted to realize super hydrophobicsurfaces by forming microstructures ornanostructures. The nanostructures of this surface

can enhance the contact angle (CA) to higher than150 , so the Water droplets that hit the surfacewould quickly roll off, carrying dust and otherparticles with them.


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If there are a high potential on the surface of the solarpanels, the charged and uncharged dusts will be attractto the panels because of the electrostatic forces. Then,the dust particles will be charged by the solar panelsfinally, so they have the same electric charge and the

electrostatic forces between them are repulsion. At last,the dust particles will float away the solar panels.However, this strategy can not be used in PV system,because of the effecting of the rain on earth.


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When the electrodes connect to a multi-phase ACvoltage, a traveling-wave electric curtain be excited.

Under the right frequency and amplitude conditions,the charged particles will not be allowed to deposit, butwill be entrained to move along the surface followingthe electric field. In this way, the surface will stay clean

of particle deposition


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In summary, we provide four observations: Dust and soiling remain problems in search of better solutions.

This is especially valid for the desert-sand regions of the world,which ironically have some of the best solar conditions alongwith some of the bestdust conditions.

Dust degrades the energy delivery of both PV and concentrating

solar systems.

Much of the mitigation has focused on the restorative approach.This included investigations of automated approaches forcleaning large systems (e.g., vehicle-mounted systems withforced water jets).

Preventative approaches included both passive methods (whichuse coatings that prevent the attachment of the dust) and activemethods (which actually repel the charged dust particles).

ppt on dust

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