International Journal of Electrical Electronics & Computer Science Engineering Volume 2, Issue 6 (December, 2015) | E-ISSN : 2348-2273 | P-ISSN : 2454-1222 Available Online at www.ijeecse.com

An Intelligent Positioning and Intensity Tracker System for Solar Panels with LCD Display

Somtoochukwu Ilo, Tochukwu Chiagunye, Aguodoh Patrick and Egbosi Kelechi Computer Engineering Department Michael Okpara University of Agriculture, Umudike

Abstract: Energy crisis is one of the most prevalent issues such as acid rain and global warming. Therefore, striking Nigeria’s human and capital development sector. conversion to clean energy sources such as Solar energy is rapidly gaining the focus as an important would enable the world to improve the quality of life means of expanding uses. To ensure the use throughout the planet Earth. The sun is the prime source of the sun’s energy at the maximum level a tracking system should be developed. Solar tracking system is the most of energy, directly or indirectly which is also the fuel for appropriate technology to enhance the efficiency of the solar most renewable systems. Among all renewable systems, cells by tracking the sun. In this paper a microcontroller based is the one which has a great chance to sun tracking system is designed and developed to ensure that replace the conventional energy the is always parallel to the sun for maximum energy output. Light intensity detecting sensors were used to Photovoltaic cells directly convert solar radiation into receive light rays and the signal processed through a electrical energy. However, the conversion efficiency is microcontroller to rotate the solar panel towards the side with not satisfactory. Unless high efficient solar cells are maximum intensity using the turning mechanism of a 5.2 invented, the only way to enhance the performance of a degrees unipolar stepper motor. The LCD display was added to solar panel is to increase the intensity of light falling on it. indicate the angular position in degrees, and a source code was written in assembly language for the prototype of the solar Solar trackers are the most appropriate and effective tracking system. method to increase the efficiency of solar panels through keeping the solar panels perpendicular to the sun. Keywords: Intelligent, Sensor, Sun Positioning, Tracking System, Microcontroller. The sun travels through 360 degrees east to west per day, but from the perspective of any fixed location the visible I. INTRODUCTION portion is 180 degrees during an average 1/2 day period A sun position tracker is a device that orients a payload (more in spring and summer; less, in fall and winter). toward the sun based on the radiation intensity on the Local horizon effects reduce this somewhat, making the payloads surface. Payloads can be solar panels, parabolic effective motion about 150 degrees. Rotating the panels to troughs, Fresnel reflectors, or . Photovoltaic the east and west can help recapture those losses. A is the direct conversion of light into electricity at the tracker rotating in the east–west direction is known as a atomic level. Some materials exhibit a property known as single-axis tracker. the that causes them to absorb photons The sun also moves through 46 degrees north and south of light and release electrons. When these free electrons during a year. The same set of panels set at the midpoint are captured, an electric current result, that can be used as between the two local extremes will thus see the sun move electricity. The photoelectric effect was first noted by a 23 degrees on either side, causing losses of 8.3%. A French physicist, Edmund Bequerel, in 1839, who found tracker that accounts for both the daily and seasonal out that certain materials including silicon would produce motions is known as a dual-axis tracker. Generally, the small amounts of electric current when exposed to light. losses due to seasonal angle changes is complicated by has two components, the "direct beam" that changes in the length of the day, increasing collection in carries about 90% of the solar energy, and the "diffuse the summer in northern or southern latitudes. This biases sunlight" that carries the remainder; the diffuse portion is collection toward the summer, so if the panels are tilted the blue sky on a clear day and increases proportionately closer to the average summer angles, the total yearly on cloudy days. As the majority of the energy is in the losses are reduced compared to a system tilted at the direct beam, maximizing collection requires the sun to be spring/fall angle (which is the same as the site's visible to the panels as long as possible. The energy latitude). contributed by the direct beam drops off with the cosine There is considerable argument within the industry of the angle between the incoming light and the panel. whether the small difference in yearly collection between Due to the limited supply of non-renewable fuels, single and dual-axis trackers makes the added complexity scientists nowadays are searching for alternative energy of a two-axis tracker worthwhile. resources. Besides, fossil fuels have many side effects 1

International Journal of Electrical Electronics & Computer Science Engineering Volume 2, Issue 6 (December, 2015) | E-ISSN : 2348-2273 | P-ISSN : 2454-1222 Available Online at www.ijeecse.com

The research is aimed at developing a tracker system that in both open loop as well as closed loop modes. The can track the movement of the sun to improve the controller was totally automatic and did not require any overall electricity generation based on tracking system. operator interference unless needed. This system consists of both electronic and mechanical Zeroual et al. had designed an automatic sun-tracker designs with several electrical sources. It has a single axis system for optimum solar Energy collection in 1997. They orientation, which follows the movement of the sun in a used electro-optical sensors for sun finding and a day from morning to evening. This tracking system is Microprocessor controller unit for data processing and for designed to automatically follow the sun and from the control of the mechanical drive system. This system input received, it can actuate some mechanism to position allowed solar energy collectors to follow the sun position the solar panel where it can receive maximum sunlight to for optimum efficiency. It had a modular structure which produce more energy output then. facilitates its application to different systems without II. LITERATURE REVIEW great modifications. The system had been applied to control a water heating parabolic solar system for Daniel A. Pritchard had given the design, development, domestic uses. Many parameters had been controlled for and evaluation of a microcomputer-based solar tracking system security such as temperature, pressure and wind and control system (TACS) in 1983. It was capable of velocity. The system had been tested for a long period in maintaining the peak power position of a photovoltaic variable illumination. The result showed that it operated (PV) array by adjusting the load on the array for satisfactorily with high accuracy. maximum efficiency and changed the position of the array relative to the sun. At large PV array system installations, Konar and A.K. Mandal had given a microprocessor inverters were used to convert the dc electrical output to based automatic position control scheme in 1991. They ac for power grid compatibility. Adjustment of the had designed for controlling the azimuth angle of an inverter or load for maximum array output was one optimally tilted photovoltaic flat type solar panel or a function performed by the tracking and control system. cylindrical parabolic reflector to get the illuminating Another important function of the system was the tracking surface appropriately positioned for the collection of maximum . The proposed system resulted of the sun, often a necessity for concentrating arrays. in saving of energy .It was designed as a pseudo tracker In 2008, Bill Lane has built a solar Tracker for his final in which step tracking scheme had been used to keep the year project. Bill lane is a graduate student, from motor idle to save energy . department of electrical and computer engineering, Cleveland State University. In his Solar Tracker project, Daniel A. Pritchard’s idea of a microcomputer was Bill Lane used a single axis design for the tracker, replaced in this research with microcontroller but no meaning the tracker only control one angle. Using the inverter or solar module was used in this project due to Cadmium Sulphide (Csd) as the light sensors, he used two cost limitations. Bill lanes idea of a single axis design was light sensors as comparator of the light radiation. When used in this work, but we used only one Cadmium one of the sensor has higher intensity of light, the position Sulphide (Csd) photocell instead of two to reduce the of the sun is on the side of that light sensor. Then, by component count and then wrote the assembly language using unipolar stepper motor, the solar panel will be rotate program to mimic the roles played by the second or move until both sensor has the same amount of light on Cadmium Sulphide (Csd) photocell. We used 8051 it. Bill Lane solar tracker is using PIC16F877 as the Microcontroller and 1-axis Solar Tracking as the main microcontroller of the tracker, the microcontroller has a element. Some hardware designs were also taken into 10 bits multichannel analog- digital converter, 5 consideration in order to design the Solar Tracking input/output ports and 256 x 8 bytes of data EEPROM System. memory. III. MATERIALS AND METHODS Ashok Kumar Saxena and V. Dutta had designed a This tracking system consist of hardware part which is the versatile microprocessor based controller for solar tangible components that drive the panel to the optimum tracking in 1990 .Controller had the capability of position by performing a set of orders and the software acquiring photovoltaic and meteorological data from a part which issues the orders performed by the hardware photovoltaic system and controlled the battery /load. part. The hardware part consist of the following These features were useful in autonomous PV systems component; Atmel89c52, LCD display, ADC0804, that were installed for system control as well as Unipolar Stepper Motor, ULN2003 Motor Driver, LDR, monitoring in remote areas .Solar tracking was achieved Resistors, and Capacitors.

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International Journal of Electrical Electronics & Computer Science Engineering Volume 2, Issue 6 (December, 2015) | E-ISSN : 2348-2273 | P-ISSN : 2454-1222 Available Online at www.ijeecse.com

ANALOG-TO- DIGITAL LCD CONVERTER MICROCON DISPLAY TROLLER

LDR (SENSOR) STEPPER MOTOR

Figure 3.1. Block diagram of Sun Tracker

The Microcontroller is interfaced to analog-to-digital panel has been rotated through the full range of converter to detect changes in voltage level of a Light movement(180 degrees from east to west) Dependent Resistor (LDR) interspersed in a voltage If the sensor output is less than 3V through the full range divider circuit. As the sun intensity varies, the voltage of movement the panel will be rotated back to the initial output varies too. This is due to the fact that the LDR position(the east),wait for the sensor value to be equal to changes its resistance with respect to the light intensity. It or greater than 3V and then rotate to track the maximum then sends the processed information to the display unit. light intensity The LCD display is programmed by the microcontroller to give the result as required. If voltage value coming from the sensor is equal to or greater than 3V which indicates that the sun is rising the System Behavior Algorithm next step is to move the panel to get the maximum light The next step is to determine if the sun rises or not, the intensity. minimum intensity of light for the system to operate The panel will be moved to the west 5.2 degrees, the two corresponds to the voltage divider output of 3V and voltage values respective to the old and new position will above. be compared by the microcontroller, if the new value is The microcontroller will check the sensor output and if it greater than or equal to the old value panel will keep is less than 3V the microcontroller will rotate the panel rotating towards the west and the two voltage values is through the stepper motor 5.2 degrees to the west. This compared again. This movement will continue until the movement won’t stop until the sensor output is 3V or the new voltage value is less than the old one, when that panel has been rotated through the full range of happens the panel will be rotated 5.2 degrees to the east. movement(180 degrees from east to west) At this point the panel is in the right position to utilize the maximum light intensity. If the sensor output is less than 3V through the full range of movement the panel will be rotated back to the initial The microcontroller will wait for four minutes before position(the east),wait for the sensor value to be equal to rotating the panel to the west 5.2degrees through the or greater than 3V and then rotate to track the maximum stepper motor, the old and new voltage values is light intensity. compared and the appropriate position will be determined in the same manner as stated above. The four minutes Prior to powering the system, the solar panel is at its interval is based on the fact that the sun moves one degree default position (east). every four minutes. The next step is to determine if the sun rises or not, the When the panel has been rotated through the full range of minimum intensity of light for the system to operate movement and the voltage drops below 3V (darkness) it corresponds to the voltage divider output of 3V and will be rotated back to the initial position. above. The sensor output will be checked by the microcontroller The microcontroller will check the sensor output and if it and when it is equal to or greater than 3V the maximum is less than 3V the microcontroller will rotate the panel light intensity will be tracked. through the stepper motor 5.2 degrees to the west. This movement won’t stop until the sensor output is 3V or the 3

International Journal of Electrical Electronics & Computer Science Engineering Volume 2, Issue 6 (December, 2015) | E-ISSN : 2348-2273 | P-ISSN : 2454-1222 Available Online at www.ijeecse.com

to the sun such as rooftops. The aim is to expose the panel for maximum hours in a day without necessarily involving tracking technologies and therefore a considerable reduction in installation and maintenance cost is realized. As such, majority of the collectors are fixed type. For fixed solar collectors therefore, it is very necessary to know the position of the sun at various seasons and times of the year so as to give the optimum orientation of the collector during installation to give the maximum solar energy all year round. Since the focus of this project was to design a solar tracker device to be used in Abia state(lat:5.110474 long:7.661109 ) as obtained from gaisma.com, the sun chart diagram of this locality is shown below. By using this chart, we can almost definitively ascertain the position of the sun during different time and seasons of the year such that we are able to fix the payload, in this case a fixed solar panel or photovoltaic cell to give us the maximum energy output. As previously discussed, it should be noted that fixed solar trackers are cheaper and therefore more preferred around countries in the tropics region, Kenya being no exception. However, for countries beyond +10degrees North and -10degrees South of Equator, there is serious need for solar tracking since the number of sunshine hour’s maybe less and/or the position of the midday sun may vary significantly.

Figure 3.2 System Behaviour Flow Chart Tracking Collectors: Improved Efficiency Fixed and Tracking Collectors For a tracking collector, the theoretical extracted energy is calculated assuming that the maximum radiation intensity Harnessing of solar energy can be done using either fixed I = 1100 W/m(watt per meter) is falling on the area which or movable collectors. is oriented perpendicularly to the direction of radiation. Taking the length of day t = 12h = 43200s, then intensity on the tracking collector which is always optimally oriented facing the Sun is compared to that of a fixed collector which is oriented perpendicularly to the direction of radiation only at noon. The collector area is marked as So. CASE I: The Fixed Collector For a fixed collector, the projection area on the area oriented perpendicularly to the direction of radiation is S = Socosθ, where θ is changing in the interval (-pi/2, +pi/2) during the day. The angular velocity of the Sun moving across the sky is ω = 2pi/T = 7.27×10-5 rad/s and the differential of the falling energy is dW = ISdt. Neglecting the atmospheric influence, the energy per unit area is Figure 3.3: Chart Showing The Position of The Sun Round The calculated for the whole day: Year in Aba City W = = 21s/ω Fixed Collectors = 3.03 * 107W/m2 day Fixed collectors are mostly mounted on the places with 2 maximum sunlight and at relatively good angle in relation = 8.41 kWh/m day.

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International Journal of Electrical Electronics & Computer Science Engineering Volume 2, Issue 6 (December, 2015) | E-ISSN : 2348-2273 | P-ISSN : 2454-1222 Available Online at www.ijeecse.com

CASE II: The Tracking Collector Earth’s surface go through the thick layer of the atmosphere in both cases. Nonetheless, the tracking For a tracking collector, by neglecting the atmospheric collector has a greater exposure to the Sun’s energy in any influence, the energy per unit area for the whole day is given day. W = IS t = 4.75 x 107 Ws o IV. SYSTEM IMPLEMENTATION = 1.32 x 10kWh/m2 day. The implementation of the system which is the hardware Comparing the theoretical results from the two scenarios structure comprising analog-to-digital converter, Light above, more energy is calculated from CASE II, for the Dependent Resistor, Stepper motor, LCD display and a tracking collector. However, the Sun’s rays reaching the microcontroller is breifly presented.

Figure 4.1 System Circuit Diagram System Operation the position on the LCD. Otherwise, it moves the motor to check for change in the sun intensity. As any change This work is made up of different units (Sub-systems) or occurs, it responds to it by adjusting the solar panel to stages that are designed to operate in a specific way new angular position. As the sun sets, the Motor is together with others sub units to achieve the expected returned back to root position and remains there until the functions. sun rises again the next day. The whole process is From the LDR sensor, the sun intensity is determined by repeated once again. the reduction or increase in resistance of the Light The IC, ULN2003A is used to drive the stepper motor dependent resistor. This is interconnected to an Analog- because the controller cannot source enough current as to to-digital converter through a voltage divider circuit. As drive it. The LCD display unit gives the information on the sun intensity varies, the voltage output of the voltage the angular position of the Solar panel in the ranges of 00, divider varies which in turn changes the step size of the 22.50, 450, and 67.50. ADC output after conversion of the equivalent voltage at its input (i.e,output of the voltage divider). This digital Test Result output is fed into the microcontroller such that whenever After the design was sketched, the source code is loaded it detects the step size corresponding to the highest in to the microcontroller. intensity; it stops the stepper motor and as well displays

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International Journal of Electrical Electronics & Computer Science Engineering Volume 2, Issue 6 (December, 2015) | E-ISSN : 2348-2273 | P-ISSN : 2454-1222 Available Online at www.ijeecse.com

Figure 4.2 Load Source Code into Microcontroller Check the CPU load to ensure the system is not over loaded, then click the play button

Figure 4.3 LCD Showing Tracker Position at Vin = 0V

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International Journal of Electrical Electronics & Computer Science Engineering Volume 2, Issue 6 (December, 2015) | E-ISSN : 2348-2273 | P-ISSN : 2454-1222 Available Online at www.ijeecse.com

Figure 4.3 LCD Showing Tracker Position at Vin Less Than 3V

Figure 4.4 LCD Showing Tracker Position at Vin Greater Than 0V

During the simulation/animation of the designed V. CONCLUSION prototype the CPU load for the microcontroller was at 31% which indicates the capability of the system when This work has presented a means of controlling a sun designed to run for years without the components tracking array with an embedded Microcontroller system. generating excessive heat. The brightness of the LCD Specifically, it demonstrates a working software solution could not be ascertained at this stage. for maximizing output by positioning a solar array at the point of maximum light intensity. This project The hardware operation after the design implementation presents a method of searching for and tracking the sun was without hitches. and resetting itself for a new day. 7

International Journal of Electrical Electronics & Computer Science Engineering Volume 2, Issue 6 (December, 2015) | E-ISSN : 2348-2273 | P-ISSN : 2454-1222 Available Online at www.ijeecse.com

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