Concept : We all are familiar with the Solar Panel : Newtons corpuscular theory of light, that light is made up of small particles called “corpuscles” which travel in straight line with a finite velocity and energy.SOLAR ENERGY : It is the major Eco-friendly & Pollution less method of producing the electricity today. Acc. to- U.S. solar research center: “ If we convert the Total Solar energy reaches to earth in one time It is a large component made up of the no of into ELECTRICITY, then it will be more photovoltaic cells connected internally with enough than whole power used by all each other. Used to grab the sunlight and to the nations per year. “ convert it into the ELECTRICITY.
What is a solar tracker ? A Solar tracker is a device usedfor orienting a solar photovoltaic panelor lens towards the sun by using thesolar or light sensors connected with themachine ( ex: stepper motor, servomotor, gas filled piston ). Hence, The sun tracking systems can collect more energy than what a fixed panel system collects.
NEED OF SOLAR TRACKERCommercial purpose :• Increase Solar Panel Output• max.efficency of the panel• Maximize Power per unit Area• Able to grab the energy through out the day .
Types of Solar Trackers 1. Single Axis Solar Tracker The suns position in the sky varies both Single axis solar trackers can either have a with the seasons (elevation) and time horizontal or a vertical axle. The of day as the sun moves across the horizontal type is used in tropical regions where sky. the sun gets very high at noon, but the days are short. The vertical type is used in• Hence there are also two types of high latitudes (such as in UK) where SOLAR TRACKER : the sun does not get very high, but summer days can be very long. Single Axis Solar Tracker. Dual Axis Solar Tracker.
2. Dual Axis Trackers Dual axis Solar tracker fig :Double axis solar trackers have both ahorizontal and a vertical axle and so cantrack the Suns apparent motion exactlyanywhere in the world. This type of system is used tocontrol astronomical telescopes, and sothere is plenty of software available toautomatically predict and track themotion of the sun across the sky. Dual axis trackers track thesun both East to West and North toSouth for added power output (approx40% gain) and convenience.
Overview of Present Tracker Drive Types Solar tracker Drives, can be divided into three main types depending on the type of drive and sensing or positioning system that they Solar Tracker Drives incorporate.• 1. Passive trackers : use the sun’s radiation to heat gases that move the 1.Passive tracker across the sky. 2.Active 3. Open Loop Trackers Trackers Trackers• 2. Active trackers : use electric or hydraulic drives and some type of gearing or actuator to move the tracker.• 3. Open loop trackers : use no sensing but instead determine the position of the sun through pre recorded data for a particular site.
1. Passive ( Gas ) Trackers Passive trackers use a compressed when the sun appears and disappearsgas fluid in two canisters each place in west & behind clouds, causing the gas in the liquid ineast of the tracker. The mechanism is in such a cylinders to expand and contract resulting in erraticway that if one side cylinder is heated other movement of the device, often causes DAMAGE.side piston rises causing the panel to tilt overthe sunny side. This affects the balance of thetracker and caused it to tilt. This system is veryreliable and needs little maintenance.Advantages :They are cheaper & effectively increase theefficiency of the solar panel.Disadvantages:gas tracker will very rarely point the solar panelsdirectly to the sun, due to the temperaturevaries from day to day and Overcast days arealso a problem can damage the panel.
2. Active Trackers Active trackers : measure the lightintensity from the sun by using “ lightsensors “ to determine where the solarmodules should be pointing. Light sensors are positioned on thetracker at various locations in speciallyshaped holders. If the sun is not facing the trackerdirectly there will be a difference in lightintensity on one light sensor comparedto another and this causes to determinein which direction the tracker has to tiltwith the help of the stepper or dc motorin order to be facing the sun.DRAWBACKS: On overcast days it will benot so working properly due to clouds.
3. Open Loop Solar TrackersDEFINATION : Open loop trackers determine theposition of the sun using computer controlledalgorithms or simple timing systems. 1. Timed Trackers- A timer is used to move the trackeracross the sky. Incremental movement throughoutthe day keeps the solar panel pointing the sun.Advantages: can be utilize as one or two axespanels.Disadvantage: Does not take into account theseasonal variation in sun position.2. Altitude / Azimuth Trackers- It uses the astronomical data or sunposition algorithms to determine the position ofsun for any given time and location by using microcontroller. Once the position has been calculated, themodules are moved using servo motors and thereposition measured by encoders built into thetracker frame.
Some Interesting Power FactsEfficiency increased by using solar trackers for one PV-cell. INDIAN POWER GENERATION 8% Thermal 3% Hydro 25% Nuclear 64% Renewable souces