AUTOMATIC SUN TRACKING SYSTEM FOR SOLAR PANELS

-By

SREEKANTH SHASTRY V

CONTENTS

• Introduction• What is a Solar Tracker ?• Need for a Sun Tracking System• Condition for Maximum Output• Basic Components• The Working• Applications• Advantages & Disadvantages• Conclusion

INTRODUCTION• EXTRACTING usable electricity from the sun was made

possible by the discovery of the photoelectric effect.

• Subsequent development of the solar cell, which is a semi-conductive material that converts visible light into a direct current.

• Solar arrays, a series of solar cells electrically connected, generates a DC voltage which can be used on a load.

Contd…• Solar arrays are being used increasingly as

efficiencies reach higher levels, and are especially popular in remote areas where placement of electricity lines are not economically viable.

• For further optimization of these panels solar trackers are being implemented, which enhances the efficiency of panels by 30-35 %.

What is a solar Tracker ?• A solar tracker is a generic term used to describe

devices that orient or align various payloads toward the sun.

• Example for payloads are photovoltaic panels, reflectors, Collectors, lenses or other optical devices.

• The system focuses on the optimization of the electric energy produced by photovoltaic

cells through the development of a sun-tracking system.

Need For A Sun Tracking System• From dawn to dusk the sun keeps changing the

angle from 0-90 rising and 90-180 declining.• In a year of 365 days the sun moves

approximately 22.5 degrees north to 22.5 degrees south of the equator.

• We get maximum energy from the sun when - The angle of the sun is degrees - The sun’s position is 0 +/- 5 degrees of the equator

Contd….• For the fluctuation factors mentioned previously,

fixed solar panels does not give higher efficiencies.• A tracking system helps the solar panels keep

oriented to the sun at the optimum possible angle.

• The tracking system improves the efficiency of solar panels by 30% for single axis and an additional 6% for dual axis.

Conditions For Maximum Output

• The difference between the incident ray and the reflected ray should be equal to zero, i.e. the rays should be perpendicular to the panel.

• The altitude is directly proportional to the efficiency of the system up to a certain limit.

• Very clear sky and clean atmosphere contributes a bit more to the efficiency of the system.

Basic Components

• The Solar Panel• Stepper Motor• Actuator • Microcontroller• A Display Unit (Optional)• Interfacing Cables

The Working

• Interfacing between hardware and microcontroller

• Inputs to microcontroller• Controlling constraints

Circuit Diagram

The Inputs

• The various positions of the sun over a year for a particular geographical location is given as the primary input to the microcontroller.

• The irradiance of the sun for a particular geographical location over a year is the secondary input for the microcontroller.

• The real time clocking is enabled in the microcontroller.

Controlling Constraints

• The microcontroller is programmed to orient the panel at optimum position against the sun, via comparing to the inputs given.

• The microcontroller is set with a lower tolerance for the voltage produced.

• If the voltage produced is above the tolerance then it holds the position of the panel.

• If the voltage falls below the tolerance, then the panel changes the position in the forward direction.

Contd…

• This voltage tolerance varies according to various seasons. Like summer has the highest voltage tolerance value.

• A second voltage tolerance is given, so as to switch off the system when it falls beyond the tolerance.

• This will help in cloudy and rainy days.• A panel will be reset to its default position at the

end of the day and starts again the next day. This is accomplished by a timer & angle limits.

Applications

• Can be used for small & medium scale power generations.

• For power generation at remote places where power lines are not accessible.

• For domestic backup power systems.

• Solar tracking systems continually orient photovoltaic panels towards the sun and can help maximize your investment in your PV system.

• One time investment, which provides higher efficiency & flexibility on dependency over other sources.

• Tracking systems can help reducing emissions and can contribute against global warming.

• Bulk implementations of tracking systems help reduced consumption of power by other sources.

• It enhances the clean and emission free power production.

Advantages

Disadvantages

• Initial investment is high on solar panels.• It’s a bit of difficult for servicing, as the tracking

systems are not quite popular regionally.• Moving parts and gears which will require

regular maintenance. • May require repair or replacement of broken

parts over a long run.

Conclusion• On one hand we can see the worlds energy

resources depletion to be a major problem.• On the other hand global warming, which is a

major concern.• Switching to solar power, which is clean and

green and enhancing its efficiency by using sun trackers is a great option in the near future .

References

• http://www.solarpoweristhefuture.com• http://www.scientificamerican.com• http://www.linak.com/products• http://www.thesolarguide.com• http://www.patentstorm.us• http://www.free-power.org• http://en.wikipedia.org • Solar Energy – Principles of thermal collection & storage By S P Sukhatme

QUESTIONS ?