Location-based Study of Effect of Tilt Angle in Soiling of PV Modules

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Location-based Study of Effect of Tilt Angle in Soiling of PV Modules

Jevin Varghese

UG Student

Department of Electrical and Electronics Engineering Amal Jyothi College of Engineering,

Kottayam, Kerala, India

Sruthimol. D

UG Student

Department of Electrical and Electronics Engineering Amal Jyothi College of Engineering,

Kottayam, Kerala, India

Robin Wilson

UG Student

Department of Electrical and Electronics Engineering Amal Jyothi College of Engineering,

Kottayam, Kerala, India

Ms. Rani Chacko

Assistant Professor

Department of Electrical and Electronics Engineering Amal Jyothi College of Engineering,

Kottayam, Kerala, India

Ms. Litty Joseph

Assistant Professor

Department of Electrical and Electronics Engineering Amal Jyothi College of Engineering,

Kottayam, Kerala, India

AbstractThe photovoltaic (PV) system converts the solar power obtained from the sun to electricity through the semiconductor materials like silicon and cadmium telluride. The photovoltaic cells have conversion efficiencies in the range of 16% to 18%. The main advantage of solar energy is that it provides green energy with no carbon emission and it is a renewable energy. Factors affecting efficiency of PV modules are temperature, shade, soiling, orientation etc. The deposition of dust particles over the panel surfaces is referred as Soiling of Photovoltaic (PV) panels. Factors affecting soiling are tilt angle, orientation, dust properties, ambient temperature, site characteristics, wind velocity, glazing characteristics, height of installation, PV technology, cell configuration and environmental effects. The atmosphere contains particles of varying sizes. The sizes will also vary in accordance with location and field. The diameter size of the inhalable coarse particles range from 2.5 to 10 micro-meters. The fine particles which are usually found in haze and smoke are in size which can range up to 2.5 micro-meters. The project study is about the effect of dust and tilt angle in the efficiency of PV modules.

KeywordsEnvironmental factors, installation factors, natural and artificial soiling

  1. INTRODUCTION

    Present world energy requirements are met mostly from the conventional sources of energy like coal, gas, and oil, which are being exploited in an unregulated manner resulting in exhausting world reserves of fossil fuels in the near future. With the increasing cost of electricity and concern for the environmental impact of fossil fuels, the implementation of renewable energy sources like solar power is rising. The main method for harnessing solar power is with arrays made up of Photovoltaic (PV) cells. Photovoltaics offer consumers the ability to generate electricity in a clean, quiet and reliable

    way. Photovoltaic systems are comprised of photovoltaic cells, devices that convert light energy directly into electricity. Because the source of light is usually the sun, they are often called solar cells. The word photovoltaic comes from photo, meaning light, and voltaic, which refers to producing electricity. Therefore, the photovoltaic process is producing electricity directly from sunlight.

    The main advantage of solar energy is that it provides green energy with no carbon emission. But solar energy is intermittent and varies depending on the environmental and climatic conditions. Despite all these benefits, the main drawback of a PV system is its limited efficiency, which ranges between 12% and 20%. Temperature and solar irradiance are two main parameters, which play a significant role that influences the generation of the output energy of the solar PV system. Besides these, there are many other factors affecting the PV performances like the photovoltaic technology used, tilt angle, array mismatch, distribution losses, inverter efficiency, soiling of PV panels, etc. The deposition of dust and other minute particles over the PV modules is termed as Soiling.

  2. OBJECTIVE

    To study the effect of tilt angle in soiling in order to increase the efficiency of PV modules for different locations and field.

  3. LITERATURE REVIEW

-Travis Sarver, Ali Al-Qaraghuli, Lawrence L. Kazmerski (2019)[1] said that the objective of this paper is on reviewing the impact of dust on the use of solar energy, history, investigations, results, literature, and mitigation approaches and also an overview of soiling problems and previous and current research and activities.

-El-Shobokshy MS, Hussein FM (1993)[2] said about the dégradation of photo voltaic cell performance due to dust deposition on its surface,degradation of photovoltaic cell performance, PV Characteristics. They also tells about the physical properties of dust particles accumulated on the surface along with deposited layer density and correlate these parameters with the degradation in the performance of the PV module.

-Vinay Gupta, Madhu Sharma, Rupendra Kumar Pachauri, K.N. Dinesh Babu (2019)[3] said that this paper is about the review on effect of dust on solar photovoltaic system and mitigation techniques and gives an overview of different environmental and installation factors that affect soiling. They also tell how to mitigate soiling using different cleaning methods.

  1. PROBLEM STATEMENT

    Soiling is the main problem that affects the efficiency and power output of solar PV modules. The efficiency of the PV module is less and makes it less economical mainly due to dust deposition. In order to make solar energy more economical in the future, a detailed study on the effect of dust deposition on the PV system based on tilt angle is need to be done.

  2. LITERATURE SURVEY

    1. General Background

      Photovoltaic technology operates by catching the photons of light which is used to produce free electrons. These electrons generate an electric current. The main way to develop this technology is through solar power panels or PV cells. A

      PV cell is a semi-conductor cell which is able to convert solar rays into electrical power [4]. A Photovoltaic solar system is composed of three different elements.

      They are:

      1. Cell: The unit where the photon- electron energy transfer is going to happen.

      2. Module or panel: The combination of several cells. The calculation of the main energy characteristics of these systems is usually referred to as the panel.

      3. Array: The combination of various panels.

    2. Types of Photovoltaic panels:

      The types of solar panels that can be found on the market related to the materials and manufactured process used is [4]:

      1. Mono Crystalline Panels: These panels are sections of a silicon bar in one piece crystallized perfectly. The efficiency of these panels does not reach more than a 24.7% in laboratory and a 16% for commercial ones.

      2. Poly Crystalline Panels: Similar to the previous type but in this case, the process of silicon crystallization is different. Polycrystalline panels are formed by pieces of a silicon bar that have been structured as disordered crystals. They are visually very recognizable because it presents a granulated surface. Lower efficiency than monocrystalline is provided by this panel and consequently, the price is also lower.

      3. Amorphous Panels: These panels have a considerable thickness. Using silicon with another structure or other semiconductor materials thinner and versatile panels can be obtained. In some cases, these panels allow adaptation to irregular surfaces. They are called Amorphous PV Solar

        <>Panels or thin film PV modules and they can be classified according to the material employed. Amorphous Silicon. Also manufactured with silicon, but differently from the previous examples. In this case, the material does not have a crystal structure. Panels of this type are commonly used for small electronic devices and small portable panels. Its peak performance in the laboratory is roughly 13% and the commercial modules of 8%. Cadmium telluride, with a performance in the laboratory of 16% and 8% in commercial modules. Gallium. Arsenide is one of the most efficient materials with 20% of efficiency on commercial panels.

      4. Tandem Panels: They are a combination of two different types of semiconductor materials. Each type of material absorbs only a part of the electromagnetic spectrum of solar radiation and because of this, a combination of two or three types of materials can be used to collect more than one of the electromagnetic spectrums. This type of panel can be as efficient as 35%.

    3. Operational System of a PV Panel

      The operation of the solar panels is based on the photovoltaic effect which occurs when solar radiation incidences in semi- conductor materials determinate internal structure and characteristics producing electricity. During the period of exposure to solar radiation, the photons give their energy to electrons in semiconductor materials, and then these electrons can break the potential barrier of the p-n junction and exit through the semiconductor creating an electrical current. The solar cells are combined in many different ways to achieve both desired voltage and power [4].

    4. Factors Affecting the Dust Deposition

      The rate of dust deposition and properties of dust is varying from site to site throughout the world. Dust deposition is the function of numerous factors, but mainly by two factors. They are:

      1. Environmental Factors

      2. Installation Factors

      1. Environmental Factors Affecting Dust Deposition

        The environmental factors are:

        1. Wind velocity and wind direction

          The wind plays an important role in dust deposition and removing dust from the surface of the solar PV module. The wind behaves like a transporting agent of dust. Slow wind can result in dust deposition while high-speed wind may clean the solar module surface. Dust deposition rate relies upon the attentiveness of airborne dust carried by air and its speed. The dust deposition rate will be more with the high concentration of airborne dust and vice-versa. The development in dust settlement is proportional to the increase in average monthly wind velocity and the minimum speed of the wind for lifting dust in Libya was 6.5 m/s. Dust deposition depends on the wind direction and orientation of the surface. Due to wind attrition of dust elements from the surface, it gets charged [5]. These dust elements come adjacent to the surface which is already charged with previously charged dust elements. The Coulomb force comes to action which may be attractive or repulsive depending on the polarity of dust particles and surface charge distribution. The attractive force will increase further dust deposition density, while the particle with the same polarity to be re- suspended in the air [6].

        2. Temperature and moisture

          The variation in temperature influences the dust accumulation process in two ways: variation in ambient temperature and variation in temperature of the front surface of the PV module. At high ambient temperature, the moisture of the surrounding area of the installation site is reducing, the local climate becomes dry. Dust can be lifted by the wind easily. In the desert and the semi-arid area where the temperature is high, the rate of dust deposition remains high. The area near the sea, where the temperature is low, may have high vapor which will condense to water drops on the surface of the PV module, resulting in the surface of the PV module becoming more adhesive and sticky that attracts more dust particles from airborne[7]. The PV module with the highest surface temperature has the lowest dust settlement densities. The cause for this is that the dust settlement process was affected by a factor, known as thermophoresis force, produced from the temperature differences between surrounding air and surface of the PV module. This force acts from a higher temperature region to a lower temperature region [7].

        3. Humidity

          Humidity extremely influences the adhesion force between dust elements and the surface of the PV module. Humidity improves the dust element adhesion because of generated capillary forces among dust elements and glass surfaces. The bonding force increases with an increase in humidity level because of the existence of condensed water in the gap between the dust element and surface which creates a water capillary link between the bead and the surface [8].

        4. Rainfall

          Light rain with less duration may increase the dust deposition. In light intensity rain, water drops can gather with airborne particles, resulting in the surface of the module get dusty. Heavy rains can un-soil the top surface of the PV module. To un-soil the surface of the PV module, a minimum of 20 mm rainfall is necessary [8]. A low amount of rainfall promotes better dust adhesion on the module which results in converting dust into mud.

          Fig. 1. Formation of formation dust deposition layers [6]

          Figure1 shows the formation of dust deposition layers, Layer A represents a rain-resistant layer, generated due to the long dry period, Layer B represents a dust layer, which produces due to the light rainfall and dry climate, can be removed by using washing and scrubbing methods. Layer C is the loose layer can be cleaned by rain [6].

        5. Dust Properties

          The dust particles play a major role in the dust deposition process. Coarser dust particles can be removed easily compared to fine dust particles with high wind speed. Because of gravity, the dust deposition rate of small particles was 5% and the dust deposition rate of large particles was 75%. Due to electrostatic charges of lesser dust elements, large dust elements affix to the lesser dust particles. Lesser dust elements exposed to solar insolation for an extensive period and fastening of ionic composites to the dust elements due to the static charging of particles [9]. Each dust particle takes specific direction by dipole moments in an electrical field, formed by the contact potential differences.

        6. Bird Droppings

          Bird droppings phenomena increase the dust accumulation on the surface of the PV module. In deserts, bird droppings accelerate the dust deposition process. This organic material blocks the sunlight from reaching the cell that causes a hotspot to form on the surface of the PV module. As a result, the area covered by organic matter becomes damaged. Bird droppings also provide adhesiveness for dust particles [9].

      2. Installation Factors Affecting Dust Deposition

        The installation factors are:

        1. Tilt Angle

          The tilt angle is another major factor that affects the dust deposition process. For the horizontal surface (tilt angle 0), the dust deposition rate is higher because of the gravitational force. For the vertical surface (tilt angle 90), the dust deposition rate is low. The vast majority of the particles depositing on the horizontal surface would be larger compared to the particles depositing on the vertical surface. The surface dust density with small particles is high on the high inclined PV module, whereas coarser dust elements accumulated with a higher rate on low inclined PV module [6]. The orientation of the PV module is essential to find out the dust deposition rate.

          The PV module that confronting the breeze straightforwardly will contract the maximum dirt deposition in comparison with, which is less showing to the breeze. The transmittance increases with an increase in tilt angle because the settlement of dust reduces with an increase in tilt angle from the horizontal axis.

        2. Height

          At a normal condition, the concentration of air-dust reduces exponentially with the height. Dust deposition is reduced if the PV module is installed at a height. The wind velocity increases with altitude, so the impact of the wind is more prominent for the PV module installed at a higher level compared to the

          ground. The deposition of dust elements influences non- linearly on the altitude from which the elements are accumulated [6].

        3. Front Surface of PV module

          The property of the front surface of the PV module, surface texture, and the additional coating also play a major role in affecting the dust deposition process. The deposition of dust is less on the glass surface compared to the Poly Vinyl Chloride (PVC) and the acrylic surface. The glass cover of the PV module is less influenced by dust deposition, in comparison to the cover prepared from Tedlar.

        4. Installation Site and Exposure Time

      Dust deposition mainly depends on the installation site. For the desert area, the rate of dust deposition is very high. In the urban and rural areas, the dust deposition rate in the urban and rural areas is different because city air temperatures are higher than the countryside surrounding temperature and wind speed

      in city zones is typically lower than in the rural region. The dust settlement rate of the PV module depends on the exposure time to outdoor environmental conditions [9]. More dust is deposited as the exposure time of the panel increases for a clean panel at the beginning. Dust deposition remains somewhat constant as exposure time increases [10].

    5. Dust Particle Physics and Chemistry

      The nature of soiling varies from location to location throughout the world. Urban areas in a northern climate might be expected to have soiling dominated by pollutants found in those environments. Likewise, agrarian locations might find species from fertilizers, windblown soil, or plant matter. In the dust studies by Cabanillas and Mungua, a group of experts identified the major sources of the dust collected from their glass surfaces in Mexico to be clay, sand, soot, mushrooms, spores, and vegetable fibers. Organic material found in the urban and agricultural areas provide the glue that contributes to holding the dust to the surface, as well as holding dust particles together. The report of the chemistry and makeup of dust from the desert regions of the world should be expected to be significantly different, dominated by quartz, feldspar and other sand components [11]. The approximate weight of different dust samples are mentioned below [12]:

      Fig. 2. Dust samples [9]

    6. Dust deposition and PV device characteristics Understanding the relationships between the physical properties of dust particles and the performance of a solar collector is potentially the critical key to develop effective mitigation and prevention techniques. The physical nature of the dust and the deposition characteristics are governed by the region of the world in which the dust studies are conducted. Fine particles have a greater effect on the

      performance of PV cells than that of coarser ones because of their ability to more effectively screen the incident sunlight. El-Shobokshy and Hussein [11] were among the first to perform investigations in a controlled laboratory environment, during which the experimental parameters could be maintained, measured, and reproduced. The purpose of their studies was to investigate the physical properties of dust particles accumulated on the surface along with deposited layer density, and subsequently, to correlate these parameters with the degradation in the performance of the PV module. They used five varieties of laboratory defined dust having distinct and identified physical properties and constituents that are frequently present in the atmosphere. Of these, three were limestone based, ground into three different grades. Cement was selected because of its presence in major building materials, and it is present in the air in most populated areas. It also is a problem in areas where cement is manufactured. Carbon was chosen because it is the product and a major pollutant in most combustion processes.

      The laboratory experiments were performed using simulators (tungsten-halogen 1000-W lamps, providing about 195 W/m2 onto the module surface) to control as many of the factors as possible and to ensure reproducibility [11]. Baseline current- voltage (I-V) characteristics for a commercial, crystalline- silicon module were documented for different light intensities. The dust was blown onto the clean panel using dry air, and sufficient time was allowed for the particles to settle. The uniformity of the dust on the panel was checked under a microscope. The dust deposited layer density was determined by wiping the surface with a number of wet rubber pieces of predetermined mass to collect all of the dust particles. The pieces were then placed in a dryer for 24 h to evaporate the water. A precision micro balance is the instrument of choice in determining surface or volume dust densities. It measured the weight of the dust by determining the difference before and after dust collection. This mass of the dust is divided by the surface area of the module was collected to determine the deposition surface density. The process was repeated several times for various densities of each type of dust. Four important parameters were measured as a function of deposition density: short-circuit current, power output, reduction in solar intensity and fill factor. The short circuit current and power output have similar trends because the open circuit voltage is not affected by the dust accumulation. From the performance characteristics the degradation in the PV performance depends not only on the dust deposition, but also, on the kind of dust and its size distribution. Finer dust accumulation on the surface has a much greater negative effect on PV performance than that of coarser particles. The decrease in PV performance is a direct result of observed increased dust deposition. Figure 3 shows PV characteristics of Short-circuit current for various particle sizes as a function of dust deposition density. In summary, dust accumulation reduces spectral reactance at every wavelength and induces diffuse reactance which can be as detrimental for solar concentrators as a reduction in spectral intensity [11]. Figure 3 represents PV characteristics of short- circuit current for various particle sizes as a function of dust deposition density.

      temperature and the PV temperature are equal throughout the period. The results

      obtained allow easy data analysis and highlight the power degradation caused by the various dust samples deposited on the different surface materials. To validate the results, mathematical equations provided by Hachicha et al. (2019) and Kalogirou (2009) were adopted used in determining the degradation of PV performance caused by dust accumulation using normalized electrical PV characteristics such as voltage, current and power [12].

      FF is the fill factor obtained from the IV tracer.

      Fig. 3. PV characteristics of short-circuit current for various particle size as

      =

      =

      (2)

      a function of dust deposition density [11].

    7. PV performance measurement using solar simulator

      A schematic diagram representing the procedure of PV performance measurement is illustrated in Fig 4 below.

      Fig. 4. Wacom continuous solar simulator [12]

      The mini module's performance was tested using a Wacom continuous solar simulator at a controlled temperature of 25 degree Celsius and was subjected to several tests using thirteen dust samples deposited on the two types of coupons. The module was initially tested without surface covering to obtain baseline performance data of the module. Then modules were individually tested with a covering of clean acrylic pastic and low iron glass coupon. The device was further tested by covering the active area with each of the dust samples from the two deposition methods highlighted above. Current and voltage data were generated, and the power data were computed to plot the I-V/P-V (current- voltage/power- voltage) curves for analysis. The effect of air vacuum between the solar cells and the coupons used was ignored since the experiment was focusing on the reduction in short circuit currents and therefore, modules were not exposed to light for an extended period to avoid temperature excitement that can lead to voltage degradation, which in turn could affect the overall output of the device. Thermophoresis was prevented during the experiment since the ambient

      Pmax is maximum power which passes through the .maximum power point when the load resistance is optimum. Isc is short circuit current; Voc is open-circuit voltage. Imax is load current which maximizes the output power. Vmax is voltage that maximizes the power output.

    8. Results and analysis

      This section presents the results of all the experiments mentioned above PV performance results, spectral results and SEM images of each dust type are presented to describe the effect of the individual sample. The mini module's IV/PV (current and voltage/power and voltage). Curve show the optimum performance of the system and its IV and PV characteristics.

      Fig. 5. Mini module's IV/PV curve [12].

    9. Evaluation of Adhesion Forces

      At the initial adhesion stage in the soiling process between dust particles and surfaces, the adhesion of dust particles on solid surfaces is governed by several forces including capillary forces, van der Waal, electrostatic and gravitational. For small particles, the gravitational force is negligible will be evaluated and compared with other dominant forces. At the initial adhesion stage in the soiling process between dust particles and surfaces, the adhesion of dust particles on solid surfaces is governed by several forces including capillary forces, van der Waal, electrostatic and gravitational. For small particles, the gravitational force is negligible will be evaluated and compared with other dominant forces. [13]

    10. Capillary Adhesion

    Adhesion by capillary forces is dominant when moisture is present in the surrounding environment. Moisture causes the

    particles to adhere to the surface through capillary action. When capillary condensation is present, water starts to condense onto clean glass surface at relative humidity (RH) well below the dew point due to the presence of small crevices causing the creation of tightly curved concave meniscus. Therefore, the capillary force is a combination of two force components, First which is the force due to surface tension and Fmc, the force due to the difference in pressure between air and the water meniscus. The capillary force is proportional to the particle diameter and is significant especially for larger particles. This effect is evident in particle adhesion on glass surfaces for which the adhesion force tend to increase slowly with RH until a critical threshold is reached, typically around 6070 RH, and then increases rapidly [13].

    1. Van der Waals (VDW) force

      London-van der Waal (dispersion) force is the force by which any atom or molecule is attracted by any other atom or molecule. In general, under dry and electrically neutral ambient conditions, the van der Waal force can be considered to be the most dominant adhesion force between the particles and solid surfaces. Nevertheless, the work presented in this paper is related to the adhesion of dust particles onto glass substrates when left to deposit for a week under an average temperature and humidity of 29 degree and 72 degree, respectively. These conditions are humid and hot which makes the capillary force to be dominant as shown earlier Where A is Hamaker constant, R is the particulate's radius and z is the separation distance between the particulate and the at substrate. The Hamaker constant reacts the strength of van der Waal force and depends on the type of materials of the particulate and the substrate in the medium of contact. Hence, the elemental composition of dominant material in the dust particles is of paramount importance to determine the Hamaker constant of the material under study. Where most dust particles in desert areas are made up of silica, the particulate matter in Qatar have been extensively studied and found to contain more calcite due to the nature of the soil in this region. In this work, Hamaker constant is taken for the system of calcite spherical particle in contact with glass substrate in water in humid and dry air, respectively [13].

      Fig. 6. VDW force promoting dust particles accumulation [13]

    2. Gravitational force

      The results show that the capillary force accounts for the forces acting on the particle-surface attraction mechanism, while Vander Waal accounts for the humid environmental conditions. On the other hand, the gravitational force is negligible compared with the other three forces as expected for particles with diameter less than 500 micrometer. The electrostatic force is as well negligible which is in agreement

      with previous studies of similar conditions. Visser stated that the humidity greatly reduces the effect of electrical forces. This is because when moisture is present, it will eliminate coulomb attraction by providing a path for dissipation of the charges, even in low humidity environment. Another reason is that the image forces are inversely proportional to the dielectric constant of the surrounding medium; hence they are 80 times weaker in water than in air. In addition, taking into consideration that glass substrate is non-conductor; the surface will tend to dissipate any near charges caused by the deposition of charged dust particles. Therefore, the electrostatic adhesion force can be significant when charged dust particles deposit on PV surfaces under dry environmental conditions, contrary to the weather in The State of Qatar where high humid weather dominates mostly all over the year. It is worth noting that there are several factors that would impact the first stage of soiling over PV. Figgis et al. have recently investigated the effects of four parameters that impact condensation on soiled surfaces: relative humidity, surface dew point temperature difference between the surface and the surrounding air, hygroscopic dust content that tends to absorb moisture from the air, and surface wettability (hydrophilic vs hydrophobic). The work utilized several natural and synthetic dust mixtures of various compositions which were studied via water adsorption isotherms, x-ray diffraction, ion chromatography and optical microscopy, on hydrophilic and hydrophobic surfaces, in the lab and field. It was found that water uptake by surface dust was strongly dependent on its content of hygroscopic material, and such material allowed microscopic condensation droplets to exist on a soiled glass coupon even when it was significantly warmer than the dew point. [13]

    3. Electrostatic force

    Fig. 7. Electrostatic force promoting dust particles accumulation [11].

    Dust particles in the atmosphere may acquire electric charge through collisions or other means. Even if the PV module surface is not charged, the charged particle will attract opposite charges on it giving rise to an image charge on the surface which induces a coulomb force, i.e. involving permanent charges of opposite sign. On non-conductive materials such as glass, surface charges can as well appear via triboelectrification with unpredictable level of charges. Triboelectrofication effect is a type of contact electrification in which certain materials become electrically charged after they come into frictional contact with different materials. [13].

    H. Methodology of Our Experiment

    Two methods of soiling are used for our study. They are:

    1. Natural Soiling

      • Glass panels of same dimension are kept outside with tilt angles (0- 45) degree using stand for one week as shown in figure 8. The angle is determined by using smart phone compass.

        Fig. 8. Experimental Setup

      • Each glass panels are then placed under a microscope to measure the particle size.

      • Transmittance is then measured using lux meter under constant illumination.

        Fig. 9. Lux meter

      • Glass panels are then placed above the solar panel and make the connections as per experimental setup shown in figure 12.

      • Switch ON the supply.

      • Take voltage and current readings by varying the rheostat.

      • Using efficiency equation given below, calculate the efficiency of the PV module.

        = X 100% (2)

        Where, is the electrical current produced by the solar PV panel, is the voltage of the electricity produced, Ps is the power of the incident solar radiation (W/m), A is the exposed area of the solar cell.

      • Fully cover the glass panels from (0- 45) degree with adhesive tape while rest of glass panels are disturbed as shown in figure 10. Repeat experiment from step 2 to 7.

        Fig. 10. Experimental Setup

    2. Artificial Soiling

    The steps are:

    • Solar panel is kept on the shelf whose tilt angle is adjustable as shown in figure 11.

      Fig. 11. Artificial Soiling Box Setup

    • Dust particles of a material of different size including the size we obtained in natural soiling are then made.

    • Particles of each size are then spread uniformly over a glass panel.

    • Transmittance is then measured using lux meter.

    • Glass panels are then placed above the solar panel and make the connections as per the circuit diagram shown in figure 12.

      Fig. 12. Circuit Diagram

    • Switch ON the supply.

    • Take voltage and current readings by varying the rheostat.

    • Using efficiency equation (2) calculate the efficiency of the PV module.

    • Repeat the experiment for other particle sizes (we obtained from the natural soiling) of same material.

  3. CONCLUSION

The performance of the PV module is significantly influenced by both environmental factors such as the wind, humidity, temperature, and installation factors such as the tilt angle, site and the front surface of the PV module. Dust settlement not only influences the performance of the solar PV module but also reduces the life span of the PV module. From this project we can see that gravity and wind speed also plays an important role in the tilt angle of the PV module. As the tilt angle increases, bigger particles fall down due to gravity. Similarly as the wind speed increases, bigger particles are carried away from the surface of glass panel.

ACKNOWLEDGMENT

The success and final outcome of this project required a lot of guidance andassistancefrommanypeopleand we areextremely fortunate to getallofthese throughout the duration of ourproject work. Wewould like to express our sincere gratitude to all these people. We thank Dr. P C Thomas, Head of the Department EEE, Amal Jyothi College of Engineering for providing support and guidance for our project. I am extremely grateful to him for providing support and guidance not withstanding his busy schedule.

We owe profound gratitude to our project guide Ms. Rani Chacko and co-guide Ms. Litty Joseph, Asst. Professors, Department of EEE, who took a keen interest in our project work and guided us all along by mentoring and providing relevant technical direction.

We would not forget to remember the unstinting encouragement of the project coordinator, Mr. Shinosh Mathew, Asst. Professor, Department of EEE, whose timely support and correction stand out as the beacons of our project. We would also like to extend our sincere thanks to Mr. K. Balachandran, Lab Instructor, Department of Mechanical Engineering for helping us to obtain the equipment needed for the project.

We are thankful and feel fortunate enough to obtain constant encouragement, support and guidance from all the faculty members of the department who helped us in the successful completion of our project work. We would also like to extend our sincere regards to all the technical staff of the Department for their timely support.

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