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8/7/2019 solar axis arvinf

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PROJECT REPORT ON DUAL AXIX SOLAR

TRACKING SYSTEM

ABSTRACT

The recent decades have seen the increase in demand for reliableand clean form of electricity derived from renewable energysources. One such example is solar power. The challenge

remains to maximize the capture of the rays from the sun forconversion into electricity. This paper presents the steps ofimplementing a dual-axis solar tracking system. This is doneso that rays from the sun fall perpendicularly unto the solarpanels to maximize the capture of the rays by pointing the solarpanels towards the sun and following its path across the sky.Thus electricity and efficiency increased.

Keywords: tracker, sensor, battery, timer,Switches.

INTRODUCTIONElectrical energy from solar panels is derived by convertingenergy from the rays of the sun into electrical current in the solarcells. The main challenge is to maximize the capture of the raysof the sun upon the solar panels, which in turn maximizes theoutput of electricity. A practical way of achieving this is bypositioning the panels such that the rays of the sun fallperpendicularly on the solar panels by tracking the movement ofthe sun. This can be achieved by means of using a solar

panel mount which tracks the movement of the sun throughoutthe day. Energy conversion is most efficient when the rays fallperpendicularly onto the solar panels. Thus, the work is dividedinto three main parts namely the mounting system, the trackingsystem and the electrical power system.In solar tracking systems, solar panels are mounted on astructure which moves to track the movement of the sunthroughout the day. There are three methods of tracking: active,passive and chronological tracking. These methods can then beconfigured either as single-axis or dual-axis solar trackers. Inactive tracking, the position of the sun in the sky during the dayis continuously determined by sensors. The sensors will triggerthe motor or actuator to move the mounting system so that the


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solar panels will always face the sun throughout the day. Thismethod of sun-tracking is reasonably accurate except on verycloudy days when it is hard for the sensor to determine theposition of the sun in the sky thus making it hard to reorient thestructure.

Passive Tracking unlike active tracking which determines theposition of the sun in the sky, a passive tracker moves inresponse to an imbalance in pressure between two points at bothEach sensor consists of two Cadmium Sulphate (CdS) lightdependant resistors (LDRs).The LDRs were placed a shadow will fallon one of the LDRs when the sensor is not pointing directlytoward the sun resulting in difference of the level of resistancebetween the two LDRs. This difference will be detected by themicrochip in the control system and will move the trackeraccordingly so that both LDRs are pointing towards the sun.Fig. 1: Sensor response once a shadow is cast on one LDRTo decide how the tracker would move, it is important toconsider the movement of the sun in the sky throughout the year.The sun path shows the annual variation ofthe path of the sun in Miri, Sun path diagram for Miri, Sarawak,MalaysiaFrom the sun path diagram, the movement of the sun in the skythroughout the year in Miri can be divided into three differentscenarios. As the sun rises from the East to sets to the West, thesun path may move in the Southern or Northern region, or it may

move almost directly overhead.If the path of the sun is in the Northern region, the structuremust be able to track the sun from East to West in anticlockwisedirection. If the path of the sun is in the Southernregion, the structure must be able to track the sun from East toWest in clockwise direction. If the sun is moving overhead, onlythe axis which tracks the angular height of the sun will move. Inall three situations, there must be a way to turn back the trackerto its original position after it has followed the movement of thesun from morning to dusk. To achieve this, limit switches areadded to the system. When the limit switch is triggered at the

end of the day, the tracker will move back to its originalposition.While the prototype has been done and tested in the lab, thispaper focuses on the design, fabrication and installation of asolar panel mounting system with dual-axis solar trackingcontroller to be tested and installed outdoors. The system is thenconnected to a battery bank via a charge controller and DCvoltage from the solar panels is converted to AC voltage throughan inverter. Improvements were made to the design of thesensor, the controller program and limit switches were added to

the system.


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FABRICATION AND INSTALLATION

The first part to be fabricated was the frame of the structure. Ateach end of the frame, a pillow block bearing is used to enable

the frame to rotate along the horizontal axis. A metal shaftwhich goes through the centre of the frame connects the twobearings. Also, the DC motor controlling the vertical movementis placed on one side of the frame. Figures 4 illustrate thefabrication parts.


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DC motoer placed at side of the frame

solar axis arvinf

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