Solar tracker and it’s economic

Submitted bySeyed Samsamoddin Naghavi Chaleshtori

University of Pune

CONTENTS Introduction What is a Solar Tracker ? Need for a Sun Tracking System Condition for Maximum OutputTypes of solar trackers Basic Components The Working Applications Advantages & DisadvantagesEconomic of solar trackers Conclusion

INTRODUCTION Conventional Energy Depletion of them Renewable Energy PV Azimuth and declination angle and Position of the sun

How the Track Rack follow the sun 1.Sunrise "Wake- Up The Track Rack begins the day facing west. As the morning sun rises in the east, it heats the unshaded west-side canister with both.

2. Mid-Morning The Track Rack moved by the shifting weight of liquid flowing from one side of the tracker to the other through a copper tube that connects the east and

3. Mid-AfternoonAs the sun moves, the Track Rack follows (at approximately 15o per hour, continually seeking equilibrium as liquid moves from one side of the tracker to the other.

4. SunsetThe Track Rack completes its daily cycle facing west. It remains in this position overnight until it is "awakened" by the rising sun the following morning.

direct and reflected rays (from the inter surface of the "shadow plate") forcing liquid into the shaded east-side cannister.

west canisters .When one canister is exposed to the sun more than the other, its vapor pressure increases, forcing liquid to the cooler, shaded side.

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 perpendicular to surface

- The sun’s position is 0 +/- 5 degrees of the equator

The main reason to use a solar tracker is to reduce the cost of the energy you want to capture. A tracker produces more power over a longer time than a stationary array with the same number of modules. This additional output or “gain” can be quantified as a percentage of the output of the stationary array. Gain varies significantly with latitude, climate, and the type of tracker you choose—as well as the orientation of a stationary installation in the same location.

Climate is the most important factor. The more sun and less clouds, moisture, haze, dust, and smog, the greater the gain provided by trackers. At higher latitudes gain will be increased due to the long arc of the summer sun. In the cloudiest, haziest locations the gain in annual output from trackers can be in the low 20 percent range.

Seasonal Variations in Output:

Gain from trackers is much greater during the long days of summer than in winter. There is strong sun for many additional hours, including the utility’s peak use hours (noon to 6 pm). Ifyour system is connected to the grid and your utility has time-of-day metering, the tracker’s ability to capture all the afternoon sun can mean money in your pocket. Time-of-day metering means that utilities purchase excess power during peak hours in summer at a significant premium, adding even more value to a tracker system. On off-grid systems, however, a tracker may not add as much value if a stationary array will produce all the power you need in summer.

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.

The graph above compares output, over the course of a year, for full tracking and a stationaryarray with the same number of modules in Sacramento, CA. The data is from NationalRenewable Energy Laboratory (NREL) web site:http://rredc.nrel.gov/solar/codes_algs/PVWATTS/version1/

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.

Types of solar trackers

I. Single-axis

II. Dual-axis

Polar type single-axis tracker

Horizontal type single-axis trackers

Single-axis tubular solar technology

Dual-axis solar tracker

Basic Components

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

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.

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.

Advantages

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.

Cause smaller size of arrayLow height and minimum visual impact.Optimization of occupied space by increasing the power

density of the park.Less expensive invertor and other componentsAll movements with DC motorsMinimum consumption per machine

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.

Fixed tilt Single axis tracker

Capacity 1 MW Capacity 1 MW

Electricity generation 1.6 million unit per

annum

Electricity generation 1.9 million unit per annum

Capital

cost(approximately)

6 crore rupee Capital

cost(approximately)

6.5 crore rupee

Unit gain of electricity generation per year:1.9-1.6=300,000

Power purchase agreement rate(assumption):6.5 rupee per unit

Extra profit for installation of single axis tracker:300,000×6.5=19.5 Lac rupee per annum

Additional investment:6.5-6= 0.5 crore rupee = 50 lack rupee

Period back of money:2.5 years

Increase in energy output over single axis tracker: (300000/1900000)*100=15.78 %

Extra investment over fixed PV:(50/650)*100= 7.69 %

Total increase in generation with respect to investment: 18.75-8.33= 8.02 % (10%)

Fixed tilt Single axis tracker

Capacity 1 MW capacity 1 MW

LCoE: ($949367.08/1900000*25)=0.0199 per kwh

LCoE: ($1028481.01/1900000*25)=0.0216 per kwh

LCoE(fix)-LCoE(single axis)=0.0216-0.0199=$ 0.0017 per kwh

Reduction of LCoE: (0.0017/0.0216)×100 = 7.87 % (8 %)

Levelized cost of Energy for Scorpius Tracker

Levelized Cost = Net Cost to install a renewable energy system divided by its expected life-time energy output.

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 .

Thank You