Solar Tracking Techniques For Renewable Energy

Solar Power as a Renewable Energy Source

The fossil fuels dearth has rooted the most daunting challenges of exploring and discovering the renewable and clean energy. Huge efforts are invested in various conservation methods, like energy recycling, energy harvesting, towards reduction in the usage of energy, in various commercial applications. Some of the methods explored, for energy renewable sources usage, like hydro power, wind, thermal power, solar power, tidal power, etc. Among them, solar power is considered as one of the most possible and easier natural sources, because of the low maintenance cost and ubiquitous characteristics of them(Sumathia, 2017).

As part of exploiting the sun and sunlight incident on the surface of the earth, there are various techniques and methods developed and implemented so that the energy obtained from the sunlight and solar power can be maximized to the best extent. Among these techniques, solar tracking stands as one of the most beneficial and viable one, to increase the solar power output, by following the incidence angle close to zero with the sun. The solar tracking motion can be a single axis tracker or dual axis tracker. The research continues to study the pros and cons of these both techniques and the differences in the energy gain.

Solar tracking with the two optional techniques are explored in terms of complexity, cost, and efficiency and majorly with the power output that can be obtained by each of this techniques. Then the design aspects are decided based on the viability and benefits of the respective techniques.

The discovery of mechanism of photoelectric current has enabled the technology to extract the electricity usable from the sun. It then enabled the solar cell development subsequently, which is a semi conductive material capable of converting direct current from the visible light. Generation of the DC voltage is then made possible with arrays of solar cells, connecting electrically.

The technology of generation of alternative power source has been achieving increased popularity, increasingly from the shortcomings of fossil fuel realization. However, solar power is generated moderately, because of more expensive solar cells, relatively and lower efficiency of conversion of them. Eventually, solar alternative power generation has been researched heavily, to decrease cents per kW/h and increased its usage compared to the other alternative power sources, such as Hydro, Wind, Geothermal, etc.

The lower efficiency is because of the reduced storage losses, inverter losses and light gathering losses. The emphasis here to increase the solar power is the incidence of the source of light that provides the power, from the sun. So, angle of incidence is directly proportional to the gathering of the light, from the surface of the solar cell, and greater the power, when it is closer to perpendicular incidence. When the surface of the solar panel is fixed, the incidence angle would be near 90⁰, in the evening and morning and then the cell’s ability to gather light would be zero that results to zero output (Sumathia, 2017). And the incidence angel would be zero, during the mid day and maximum output of power collected by the surface of the cell, since light incidence is perpendicular, on the panel.

Solar Tracking for Maximizing Solar Power Output

So, the key to increase the efficiency and power output is to maintain the incidence angle to 0⁰, to the possible extent. It can be achieved by solar panel tilt, to face the sun, consistently. This sensing and tracking or following the sun in real time, is called solar tracking.

Since solar power is available for about ten hours, everyday, it can be the best utilized. So, there have been various techniques developed and implemented, towards maximizing the solar power and energy obtained. Solar tracking is one of such techniques. Solar tracking is done in one of two techniques called 1 axis tracker and dual axis tracker.

The simple method for solar tracking is to use a Light Dependent Resistor that can detect the changes of light intensity, on the resistor’s surface. Two phototransistors can also be used, as an optimal method for tracking process.During the morning period, tracker would be in the state of A, turning the left phototransistor on and result in motor turn on. This process is continued till tracker is moved to state B, returning the shadow from the plate. Later state C is shortly reached, as the progress of the day and turns the right phototransistor on. Turning of motor continues till reaching of the minimum level of detectable light.

The design has a challenge that the sensitivity range is narrow, because of the phototransistors used and with bias conditions. So, better method can be proposed with the set-up of a simple triangle, taking two solar cells and connecting in opposite directions, as shown n the figure below.So, the set-up makes lighter to fall over one of its solar cells and increased potential, resulting in difference of voltage between the two cells. The design would result in signal to detect, at each cell, however, at mid-day the light fall is less, because of varied incidence angle.

Then the experiment was tested by employing the fixed panel surface by removing the tracking system and another, by employing the tracking system (Rizk & Chaiko, 2008). The resulting readings have shown the changes in the output powers obtained in these two conditions.The results are obtained after a period of 12 hour, as follows.

Surface	Output Power	Average Power	Average Percentage
Fixed	9W	3.51W	39%
Tracking	9W	6.3W	71%

Table: Fixed and Tracking Systems

During the later and earlier periods of day, fixed panel power increase is up to 400%, with an average of 30% increase of power, when the solar panel is maintained in perpendicular position to the sun, to the possible extent. (Rizk & Chaiko, 2008)

Single-Axis vs Dual-Axis Systems

The method and mechanism of the solar tracker has its objective to follow the direction of sun, so that maximum power can be extracted. The possible drive types can be as the following.

The passive tracker follows the principle that solar heat is taken as an input for an imbalance and it leads to the tracker movement, working on thermal expansion and employing either shape memory alloys or low boiling point fluid of compressed gas.

Passive trackers have a fewer applications, because the applications of CSP (Concentrating Solar Power) demand higher precision, efficiency and higher degree of complexity. But they have applications in the regular flat PV systems (Sumathia, 2017).

A passive tracker with single axis is designed with lost cost based on SMA (Shape Memory Alloy) actuators, since this actuator can be deformed easily, with even lower temperatures. So, when it is heated above the temperature of transformation, mechanical work is produced and original shape is returned.

The experimental study proved that passive tracker can provided about 2% of efficiency.

The active tracker can have better control over the tracker, by the mechanisms of gear and motors, for better direction and magnitude. These are widely used, for its accuracy and efficiency, however, needs additional power and energy consumption.

The system of single-axis offers one degree, acting as the rotation axis. So, they have lesser complexity and consume only small energy, compared to the system of multi-axes.An experimental study was performed and 3 position 1 axis PV with sun tracking system, mounting on the building wall, for operating in total three different angles, as shown in the figure above. The PV mounting frame is set to turn with a DC motor and structural design. The tracker turning is enabled with a timer IC, offering the time signal, for motor triggering, to turn the angle of turning. A microcontroller is used for implementing control algorithm (Huang et al., 2011)

This typical system of PV standalone, has a servo motor, PV panel, LDR sensors, PV panel, microcontroller and external load. Motor is set for single-axis rotation freedom.Different experimental studies were performed with single axis angle and the results are reported and recorded comparing with the radiation collected from a regular horizontal surface (Sumathia, 2017). They report from conclusion that a tilt of horizontal surface, raising optimal angles, at about 30.2% more radiation, in one year. However, when a two axis azimuthally is compared, about 72% of more radiation is recorded.The azimuth schematic diagram can be as follows, for a tracking of three steps (Bin et al., 2011)

Passive vs Active Tracking Mechanisms

According to Chang (Chang, 2009), the tracking panel performance with varied latitudes, time periods and types of radiation, concluded that the single axis, east-west oriented system has lesser yearly gains, compared to north-south.When compared to the non-tracking collector of CPC (Compound Parabolic Concentrator), one-axis system increases the optical efficiencies. But there were significant effects, with even smaller errors in tracking.

Further analysis is done with two positional tracking system daily (Tomson, 2008) and positions, both symmetrical and asymmetrical, derived in the axis of north and south. More gain is obtained with two positional exposures. 45 degrees of tilted collector and South-East direction, with westward +60 degrees deflection and -30 degrees of eastward deflection gave maximum gain.

When solar tracker was employed to test at varied day times, the following readings are found, as shown in the following table.

Time	With Tracking	With no Tracking
9 AM	21.8 V	20.5 V
1 PM	22.6 V	21.5 V
5: 30 PM	19.5 V	18 V
9 AM	18.8 V	18.4 V
1 PM	19 V	18.6 V
5: 30 PM	18.2 V	18 V

Table: Solar Tracking Results in Sunny and Cloudy Weathers

There are more differences in voltages, during sunny conditions, from the Table above.

It gives freedom with two degrees and acts as rotation axes and are set in perpendicular directions to each other, giving better accuracy, from more complex control system. It makes uses of normal tracking and daily adjustment strategies. Normal strategy has smaller tracking errors and improves performances.

In certain areas, the techniques for solar tracking are found to be unsuitable, for low solar resource areas, because of stronger correlation in between solar resources, found in that area and increase of solar gain, yearly.

A multi-axes electromechanical system can be designed and implemented, through PLC (Programmable Logic Control), for tracking the sun, and calculate solar altitude and azimuth angles, according to Sungur (Sungur,

2009). This system minimized the errors.

Two axis tracking collectors are incorporated by Njoky, for energy generation improvement through solar PV system.Rotation about the central axes can be observed from the above figure, for the same system (Njoku 2016). Oner et al., designed microcontroller controlling spherical motor, for solar tracking precisely and found that the motor can move the panel in both vertical and horizontal axes, instead of two different motors for each axis (Oner et al, 2009).

When both one and two axes trackers are experimented with sun zenith, azimuth, solpe and surface azimuth angles, for surfaces of optimum geometry of fixed and tracking, two axis tracking surface provide maximum radiation beam possible, when sun and surface azimuth are equal and when Zenith and surface slopes are equal, according to Braun et al. (Braun 1983)

Experimental Studies on Solar Tracking

Solar panels MPP (Maximum Power Point) and efficiency improvement can be achieved by an algorithm called MPPT or Maximum Power Point Tracker, according to Huang et al. (Huang et al. 2012). The technique is to implement the operations called SDT (Slope Detection Tracking) and open circuit tracking, for raising the accuracy and tracking speed. Here, SDT increase the duty cycle of switching and so solar panel current is also increased, ensuring the MPP operation.

When static MPPT technique is considered, the technique of golden section provided 99.43% of rate of efficiency, which is more, in lesser response time. And dynamic tracking is more preferable for its 99.602% of efficiency, in 0.025s convergence time, when the complexity level is low (Kheldoun et al., 2016).

A new hybrid control strategy is presented by Rubio et al., for more accurate sun tracking and energy saving factors. Algorithm is developed to work in two modes,

Normal mode of tracking, when sunlight is sufficient
Otherwise, search mode

It showed that this model gave more energy generation (Rubio et al, 2007). An interesting algorithm is proposed for sun position calculation, for sun tracking without using the sensors. The algorithm calculated elevation and azimuth sun angles in horizontal coordinates. It improved 49% of energy efficiency and suitable for the applications, where there is no requirement of more accuracy (Rizvi et al, 2014).

A new system with tracking and cleaning is proposed and improved 30% of energy generation than without cleaning. It used 8051 microprocessor, gearbox coupling to stepper motor along with a mechanism of sliding brush (Tejwani & Solanki 2010).

The reception of the irradiation is tested to be the same for both the systems of one and two axis, but the later cost is much more than the former one. They reported 54% of more irradiance is more compared to fixed systems and both have received surplus energy of 34% and 38% (Nann, 1990).The gain of the PV tracking system can be improved to 40%, by V-trough concentrator implementation, by using amorphous Silicon solar cell (Shaltout et al, 1995).

Tracking helps reducing the incidence angle in between panel and incoming light and increases the energy produced, in the PV systems Optimum tracking strategy was studied, for solar PV system, in higher latitudes and concluded that integrated solar radiation incident over the horizontal plane theoretical value estimation shows that PV panel on a horizontal plane produces increased energy compared the one tracking or following the sun. So, the study concluded that option of tracking is viable, only during partly cloudy or clear sun (Guillermo et al, 2015).

Conclusion

When active solar tracker of one axis is designed, modelled and tested, 20% increase is shown in efficiency than the design of fixed panel, through there are slight deviations, in the periods of afternoon and evening, because of wind loading, mechanical friction, etc. (Chin et al, 2011).

According to Yao et al. (Yao et al, 2014), normal tracking strategy obtained more power output than the system of fixed PV. About 31.8% of more efficiency is obtained with the tracking process.

The tracking system energy efficiency is studied with energy absorption model, by Zhang et al., revealed that the energy absorption is too less and tracking is unsuitable for the too high latitude of 85 to 90 degrees, though 36% of energy efficiency average value, for a year can be obtained, theoretically.

An increase of 42.6% energy is obtained from the multi-axes sun tracking system, when controlled by an along module and PLC, at 37.6 degrees of latitude, compared to fixed PV panels (Cemil, 2009). Solar tracking offers uniform distribution of energy and its gain, for the entire day and so is more efficient (Pratik, et al, 2015).

Distributed MPPT module helps PV system efficiency optimization, especially, in partial shading on the system conditions, compared to centralized MPPT. It can compensate the loss of generating capacity, because of the problems of mismatch to 50%, according to Mei-xia et al. (Mei-xia et al, 2012).

According to Mei-xia et al., when the centralized and distributed MPPT output characteristics for PV panels are analyzed, and found that DMPPT can have 96.54% of efficiency delivery with full possible efficiency capacity of 98.41% that is more than the European and CEC efficiency, even at 10% of power point, indicating potential to great generation efficiency improvement (Mei-xia et al, 2012).

Solar tracking efficiency is tested and experimented for efficiency in cold and hot climates. In Egypt, a hot climate, there is only 8.16% of energy gain in hot climate, compared to the no tracking and such low output is because of the panel overheating with consumption of total energy generated to 5.89%, out of total generated energy in sunny day. In Berlin, with solar irradiance and low ambient temperature, there was 40% of energy gain more than non-tracking panel, giving 30% of final energy gain, after subtracting 10% of consumption by tracker. So, solar tracker system is unsuitable for the extremely hot climates (Eldin et al, 2016).

The average performance ration of PV system, rp is close to 0.75, for 2-axis solar tracking, in Nigeria and it is increased with latitude. About 20% to 40% of more production of energy found, according to Njoku (Njoku, 2016).

According to Quesada et al., sun tracking system is unsuitable in cloudy days, during the summer, during the conditions, IH (global solar radiation incident over the horizontal plane), is lower than Ic (critical radiation), producing 25% lesser generation of energy, than horizontal panels (Guillermo et al, 2015).

The overall efficiency and power output of the solar tracking PV panel can be made optimum with the tilts angle and their correlation, since the solar radiation reaching the panels of photovoltaic would be varied according to the changes of the corresponding tilt angles. The other factors are the geographic position, conditions of local climate and usage time period. The tilt angel choice by the engineer can be simplified by the correlations (Enslin 1992).

The daily optimal angle can be obtained by the extra terrestrial radiation incident equation derivation, on a plane collector that faces towards south, so, S_opt is considered as the tilt angle, δ as the declination and L, as the latitude.

Equation I

———————– (1)

The correlation for monthly optimum angle can be proposed as the following.

From the month of January to March, so M varying from 1 to 3

S_opt = 60.00012 + 1.49986M + 3.49996M² + (L-30) (0.7901 + 0.01749m + 0.0165M²) ——————————————————————— (2)

For the months, from 4 to 6,

S_opt = 216.0786 + 72.03219M + 6.00312M² + (L-40) (1.07515 + 0.11244M + 0.03749M²) —————————————————————- (3)

For the month, M value from 7 to 9,

S_opt = 29.11831 – 20.52981M + 2.50186M² + (L-50) (-11.17256+ 2.70569M+ 0.15035M²) ——————————————————–(4)

For the months, M from 10 to 12,

S_opt = -441.2385+ 84.54332 M – 3.50196M² + (L-340) (4.2137 – 0.54834M + 0.0223M²) ———————————————————————– (5)

The equation (2) is further corrected by Souleyman (4) and then obtained as,

S_opt= 60.00012 + 1.49986 M – 3.49996 M2 + (L-30) (0.7901 + 0.01749 M +0.0165 M²) ——————————————————————– (6)

Another correlation was proposed by Trisis (5), with the measured data, as the following.

S_opt = 35.15 – 1.39 δ – 0.007 δ² – 4.26 x 10 -5 δ³ ————————– (7)

The orientation and tilt angle are important for the module of the photovoltaic, as factors, influencing the overall performance of them. (Hussein et al, 2004). According to the experiments and studies conducted by Tsalides et al., (Tsalides & Thanailakis, 1985), the tilt angel effect on the generator of the photovoltaic, by optimum tilt angle calculation, for the 1960 to 1983 period, in the geographical location of Athens. The studies have concluded that the photovoltaic panel inclination optimum angle is found to be average annual clearness factor linear function, K^T.

Sopt = 70.5 K^T + 24.125 ——————————————————-(8)

Then the correlation is found to have the regression coefficient of 0.96.

Correlations are validated by connecting the photovoltaic panel to a fixed resistor, according to El-Kassaby (El-Kassaby, 1988). The system tested has not been contained most extraction of power, however, good results are obtained by the correlations developed (Mraoui et al, 2014).

Solar energy measurement is done for the purpose of recording the diffuse and global radiation on a horizontal plane. The radiation over the surface tilt would be calculated, along with the precision related, from the parameters measured and the position of the sun in the sky (Mraoui et al, 2014).

So, the position of the sun can be calculated by the number of the day, N, local geographical coordinates and the solar time and they have to be well known. From this set of data, hour angle, and solar declination, that are taken as coordinates of horizontal and solar altitude, with respective to the instantaneous azimuth, a (Mraoui et al, 2014).

The above figure shows the radiation of solar on the arbitrary surface that has S, the inclination, according to the horizontal. It is calculated as sum of sky diffuse radiation (G _d,s) and beam radiation (G _{b, s}) and the reflected radiation on ground (G _{gr, s}) (J. A. Duffie and W. A. Beckman, Solar Engineering of thermal

processes, 3rd ed. John Willey and Sons, 2006).

So, G ^T,S = G ^b,s + G ^{d, s} + G ^gr,s ————————————————— (9)

Let us assume that the diffuse distribution of the solar radiation is isotropic, in the atmosphere,the value can be obtained over the tilted surface, by measured diffuse radiation multiplication, through the view factor over the sky on the horizontal surface (Duffie & Beckman, 2006).

———————————————————– (10)

A simple method is presented by isotropic model, for the diffuse solar radiation evaluation, over the inclined plane. But the solar radiation received is underestimated by the model, especially, for the conditions of the clear sky. Here, it makes use of the Perez Anisotropic model (Perez et al, 1990).

The diffuse radiation would be split into three different components, by this model. These components are the horizon that can brighten the radiation, the circumsolar radiation that surrounds the disk of the sun and the diffuse radiation, distributed, isotropically, from the sky of the rest.

————- (11)

Here,

F1 = coefficient of circumsolar brightness

F2 = coefficient of horizon brightening

a1 = max (0, Cos(θi))

and

a2 = max (Cos(85), Cos(90-h))

Then the solar radiation from ground reflection can be calculated by the total horizontal surface radiation by the ground reflectance and the view factor, relative, to the ground.

Here, ρ is the factor of ground reflectance, depending majorly over the properties of soil reflectance. The study uses the value of 0.3 for Ghardaia and 0.2 for Algiers.

The study made use of the data measurement, after collecting and recording from two different geographical locations, called Ghardaia site and Algerian site. Here, the Ghardaia site is located in the Algeria’s desert, towards north, with the altitude of 468m, longitude of 3.8⁰E and latitude of 32.4⁰N and the site, Algerian is located towards northern part of the Algeria, with 345m, longitude of 3.8⁰E and latitude of 36.8⁰N.

The climate of Ghardaia is categorized as the arid dry and hot, or BWh and the Algiers climate is more of temperature climate having dry and hot summer, Csa, according to the classification of the Koppen-Geiger.

The parameters collected here are the radiometric, principally, such as global radiation incident over the tilted surface at the latitude site, diffuse solar radiation and horizontal global radiation and direct radiation. All these parameters are collected. The study also collected some of the parameters of weather, like atmospheric pressure, relative humidity and air temperature that is dry.

The pyrheliometers mounted over tracker of 2AP dual axis and positioned, which is used to provide the sun reliable positioning measures the directed radiation. The diffuse irradiance can also be measured by the ability of 2AP having Shading Ball Assembly, with pyranometers that are mounted properly. Here, the radiometric devices used are in compliance with the secondary standard of ISO and the rate of error would not exceed 2%. And the meteorological devices error also would not exceed 3%.

The solar tracking PV panel system has its electronic circuit, on the basis of two photo resistors resistivity comparison.The fact identified is that the maximum radiation from the sun can be received by the PV module, or solar collector, when the rays of the sun strike them in right angles. So, optimal angle of tilt is dependent on the application of the solar power system and latitude of the site.

A unit of programmable logic controlling can be used for the system of sun tracking in single axis. The control operation can be obtained by developing controlling program, suitably. And it becomes the heart of the solar tracking system.

The position of the sun can be tracked with symmetric photo-resistors, positioning in the PV solar module holder and shadowing is provided for one resistor out of two, by separating them with a solid barrier. When the more sunlight gets incident on the resistors surface, their values are decreased. It allows decreasing the resistivity and so dropping of voltage across the resistor. Then drop of voltage is increased on the variable resistor (Al-Mohamad, 2004).

The tracking system can be well controlled through program customized for the PLC, with the benefits of,

Controlling the movement of the tracking system
Monitoring the outputs and inputs of the PLC
Storage of samples

Special programs built for effective tracking system, such as,

Automotive port detection
System monitoring
Display of the system of sun tracking
Movements of the module, towards forward and backward, in the situations unexpected

The solar tracking system, either with the single axis or dual axis, it is implemented with the help of the microcontroller. So, every solar PV system that is referred to design in the recent and in the future would be based on the microcontroller that is used to automate the processes that they are intended to do. The motion of the solar tracker and its associated measuring functions, generation of the photovoltaic and the central and control algorithms are built in the microcontroller and so it implements the basic function and program of the solar system.

The function of the microcontroller in the solar tracking system is started by receiving the inputs from the Light Dependent Resistors, which pass the intensity of light, incident from the sun. The input from the LDR would be then processed and the microcontroller enables the functions of the processing units, such as enabling the motor driver to operate and turn the solar panel to respective direction. The stepper motor would be driven by the motor driver, in the greater illumination direction, by turning the panel, of one step at one time. The motor continues to move, till the sensor values difference would reach below the value of threshold. So, every microcontroller in the solar tracking system is designed and built to receive the input from the sun and enable the processing units to achieve the output, required, in terms of output power.

So, every photovoltaic standalone solar tracking system has basically a panel made with photovoltaic, battery, servo motor, LDR sensors, charger and external load, along with the microcontroller to enable the function of the solar system.

The fixed sun tracking PV panels and single and dual axis solar tracking PV panels are also compared, in terms of their gains, in each month of the year.

Month	Sun-Tracking Fixed systems	Two-axes and Single axis Systems
January	9.03	12.16
February	13.19	17.33
March	17.72	21.30
April	30.60	25.06
May	42.91	29.22
June	48.77	31.14
July	49.02	32.09
August	35.30	27.07
September	25.06	26.89
October	14.46	18.75
November	10.52	14.32
December	8.93	12.70

Table: Monthly Gains for Fixed Tracking and 1 and 2 Axis Tracking Systems

From the literature reviewed from the available resources, the key point can be conceived as the mechanism of electrical energy produced from the global solar irradiance collected that depends again on the ways of tracking the sun accurately, by the system. Among various mechanisms and designs developed and implemented in the study, a significant mechanism can be understood as the two axis solar tracking that has achieved the capability to track the sun continuously, resulting in receiving the solar beam on the surface with the key incidence angle value, zero. It shows definite improvement compared to the traditional fixed system and single axis sun tracking systems. The system of single rotating axis, in various studies tracked the sun azimuthally, only consequently, the system’s incidence angle to follow the position of the sun, based primarily on the panel slope and rotating axis choice.

Crystalline silicon PV panels deteriorate performance, when heated. Moharram et al. Research concluded that the PV panels temperature coefficient, indicating decrease of 0.5% efficiency, by 1⁰ of rise of temperature (Moharram et al, 2013).Solar tracking is beneficial and high performing, in the countries that are cold and cloudy, instead of the sun-belt countries, according to the experimental studies, by Eldin et al. (Eldin et al, 2016).

Solar tracker working range can be increased with LDR special arrangement for a solar tracker of three dimensional, PLC helps solar tracker position control and 3D solar panel have better capacity to produce increased energy, compared to the traditional one, according to Pratik et al (Pratik et al, 2015).

PV panel performance can be increased with hybrid sun-wind tracking system that combines system of dual-axes along with the system of wind-tracking for PV panel cooling. It increased 49.83% of performance compared to conventional system. And wind-tracking system can complement the tracking of dual-axis, during windy conditions and works as an auxiliary system (Masoud et al, 2015).

According to Koyuncu et al., sun tracking system with two-axis microprocessor, optimum energy is received, as long as the panel plane is maintained to be normal to the sun (Koyuncu, 1991).Efficiency of dual axes solar panel is increased significantly, with timer and mechanism of dual axes LDR sensor.

According to Laughlim et al (Laughlin et al, 2013), the installation costs can be reduced with two axis solar tracker of low profile, by securing the system towards the ground and improving the density of packing through smaller shadow footprint creation, compared to the regular trackers.The cost of the one axis three panels is not more than a system of fixed PV rooftop (Huang et al, 2011).

Cost effectiveness and performance of the tracking system, at various modes are analyzed by Michaelides et al. The three modes are seasonal tracking, adjusting the slope, one axis tracking, with azimuth variation and fixed surface at 40 degrees to horizontal. The study used simulation program, TRYNSYS and concluded that the best performance mode is the single tracking system, with the annual friction for

Single tracking – 87.6%

Seasonal tracking – 81.6%

Fixed tracking – 79.7%

However, fixed tracking is most cost-effective (Michaelides et al, 1999).

The research conducted for “An efficient engineering method to maximize PV output from Solar Panel” has been started from an effort of understanding the meaning of the solar tracking. Initially, an attempt is made to search and find the basic literature from the library and internet resources. Authenticated resources are collected as PDFs. Then all the resources are arranged in the logical sequence to read and understand.

A detailed understanding of the solar tracking is attempted, so that the basic technology involved in the solar tracking is explored. Then the key question to increase the performance and efficiency of the solar tracking is attempted to explore. Eventually, incidence angle is considered as a key and significant factor for increasing the power output and so can increase the efficiency of the overall, going back to the basics (Sumathia, 2017).

The literature has shown several experiments conducted by the experts previously. Each of the experiment has been studied and the details of each of the experiment are recorded. The recorded details and readings of the experiments have been reviewed to understand the key factors to increase the power output to maximize the output of the photovoltaic panels. The exploration gave the key methods of increasing the tracking effect of the solar panel. Single axis and dual axes solar tracking panel system has been explored in detail in the study. The literature has been explored and reviewed to understand the methods to maintain the incidence angle of the solar panel surface, by the solar panel, with the process of tracking. The detailed methodologies are studied.

The research is further extended, after a fair understanding of the solar tracking system and its optimizing methods. A fair idea has been developed after a clear understanding of the key factors that can improve and increase the power output of the PV cells.

There are several current commercial solar tracking systems available with the microcontrollers. Initially, microcontrollers have only limited function, however, with the advancement of the technology, microcontrollers have got master control of the solar tracking system. So, each and every key component used in the solar tracking system is controlled by the built-in programs of the microcontrollers. The master control microcontroller ensures the operation of each of the component and unit and ensures that the incident angle is maintained close to zero, with the sun.

The design aspects are reviewed and analyzed for the design of the solar tracking system with PV cells. The design is going to be with the dual axis solar tracking system, since higher output power is the aim of the research. Another important aspect and consideration of the efficient solar PV panel is the consideration of the cost.

The cost of the solar panel is expensive, when the dual axis system is considered to develop. It is because of the increased complexity and expensive hardware required for the design of the system. So, MPPT algorithm is considered to employ the methodology that can reduce the need of the hardware and improve the efficiency and power output of the PV panel, with solar tracking system.

The final design would then be simulated in MATLAB and the results will be obtained, for comparison with theoretical results.

Tracking systems are designed and implemented with single and dual axes. The objective of single axis tracker is to follow the apparanet movement of sun from east to west and the dual axis tilts the solar module or collector, for tracking the changing altitude angel of the sun, in addition to the tracking from east to west.

Bifacial modules that are mounted over the sun tracker of polar axis have the ability to grab about 1.7 times of the global solar radiation energy, when the static modules and mono facial modules are compared, according to Oria et al. (Oria, & Sala, 1988).
There is about 36% of increased output of annual energy received, by employing the sun tracking system of dual axis, when the PV system of fixed latitude tilted are compared, according to Chander et al (Chander, M & Chopra, 1988).
About 42% and 36% of power generation gains are obtained in the mid latitude region, when the dual axis and single axis systems are used for sun tracking, respectively, when compared to the photovoltaic system with fixed arrangement, according to Neville (Neville, 1978).
Optimal tilt angles and optimal orientation for collectors of the flat plate solar, in Egypt can be found and obtained by the mathematical model development and the concluded that the total 29.2% of total additional energy can be achieved, by changing the title angles as well as the orientation, on daily basis, when compared to the fixed panels, according to Morcos (Morcos, 1994).
The photovoltaic modules that got mounted over the sun tracker of dual axes performance was studied by Kaira et al. (Kacira et al, 2004) and concluded that about 29.3% and 34.6% of additional radiation of solar and production of electrical power, reached respectively, compared to the fixed PV panel, in Turkey, on specific day in the month of July.
According to Chang (Chang, 2008), the one axis solar tracking panel gain is considered, to extraterrestrial radiation following and concluded that the 36.3% and 62.1% solar radiation gains are obtained, for specific four days, in the year, and for specific four seasons, it is found to be in between 37.8% and 60%. The solar radiation gains are obtained to 49% when considered throughout the year.
In a theoretical study presented by Chang (Chang, 2009), the output of the electrical PV module in varied tilt angles and azimuth angles in Taiwan and the PV module mounted gain over the sun tracking of single axis is analyzed against the fixed panel. The study and analysis indicate that the gains yearly, achieved from the observed, predicted and extraterrestrial radiations are 18.5%, 28.5% and 51.4%, when a PV panel with single axis is installed. About 17.5%, 25.9% and 45.3% of the same parameters are obtained, when optimum slope is considered in the installed single axis tracking solar panel. Here, the optimum angle is adjusted for the PV panel, for each of the months.
Another theoretical study conducted by Chang, in the third study, (Chang, 2009). The study is conducted over the oriented single axis in the East-West and concluded that the gains achieved are much lesser compared to orientation of the North to South, panels of single-axis systems. So, for the observed, predicted and extraterrestrial radiations, the obtained improvements in the gains obtained are, 7.4%, 13.5% and 21.2%.
A new mechanism was developed for the sun tracking system of one axis by Huang et al (Huang et al, 2007), having adjustment positions of three fixed angles, in the morning, in the noon and in the afternoon periods and the mechanism has achieved 24.5% of increased generation of power, compared to the fixed panels.
A multi-axes system for sun tracking has been designed and constructed, in three axes, East-West, North-South and Vertical), by Abu-Khader (Abu-Khader et al., 2008). The findings from the study are that there is an overall improvement of output power to 30% to 45%, from the axes tracking system of North to South, when compared to the system of fixed PV panel.

Conclusion

The mechanism of sun tracking increases the solar energy radiation, receiving from the photo voltaic modules or solar collectors, resulting in increased harnessing of output power daily and annually, when compared to the fixed solar panel system. At the same time the tracking system usage is offered with more complex and more expensive deal, for an average increase of more than 25% of more output power, compared to the fixed solar PV panel system

Solar tracking system can be optimized with single and dual axis systems that can increase the power output compared to the fixed solar tracking system. The purpose of the single and dual axis systems is to maintain zero incidence angles with the progression and movement of the sun.

Though tracking with PLC technologies towards tracking system control and solar panel monitoring are increasingly complex and expensive, compared to the fixed ones, when these are used for the applications of controlling with more modules, deployed simultaneously, can become cost effective, as this system can obtain increased power output for throughout year.

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