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The Impact of Tilt Angle on Photovoltaic Panel Output

Article · December 2017

DOI: 10.21271/ZJPAS.29.5.12

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 ZANCO Journal of Pure and Applied Sciences
The official scientific journal of Salahaddin University-Erbil
ZJPAS (2017), 29 (5); 112-118
http://dx.doi.org/10.21271/ZJPAS.29.5.12

The Impact of Tilt Angle on Photovoltaic Panel Output

Sarkar Jawhar M. Shareef

Department of Electrical Engineering, College of Engineering, University of Salahaddin, Kurdistan Region, Iraq

ARTICLE INFO ABSTRACT

Article History: PV (photovoltaic) panels are getting more attentive in our life due to its
Received: 05/03/2017 big advantages. At the same time its efficiency is an important factor to
consider. At any location on the earth its output is affected by its tilt and
Accepted: 13/07/2017 azimuth angles. These angles play an important role in the efficiency of the
Published: 28/12/2017 photovoltaic panel. In this paper, the effect of tilt angle on PV performance
Keywords: determines. The PV module tilt angle changes from 0° to 90° using Arduino
Mega 2560 to control it. The values of the PV panel output voltage collects
PV panel using the Arduino and output power calculates at different tilt angles to
Tilt angle know the effect of tilt angle shift on the PV panel output. A mathematical
Output power equation derives to calculate the effect of tilt angle on the PV output.
Arduino
*Corresponding Author:
Sarkar Jawhar M. Shareef
sarkar.mohammed@su.edu.krd

1. INTRODUCTION Thus, it is very important to orient the PV

Energy requirement increases due to panels at tilt angle for any given location to
technology improvement every day can never obtain maximum power output. PV panels are
be fulfilled by the generation from fossil fuels. most efficient when they are perpendicular to
Thus, power generation from renewable the sun's rays. Figure 1 shows Azimuth and Tilt
energies should be considered. The solar angles (Weir, 2006).
energy attracts large interest out of other
renewables, because of its great advantages
like it is easy to install, minimum maintenance
required and more.

1.1 Solar Angles

The sun's position in the sky as per any
location on the earth could be located using the
solar angles (Tilt and Azimuth angles). The tilt
Figure 1: Solar tilt and azimuth angles
angle plays important role towards the
efficiency of the PV (photovoltaic) panels.
113 M. Shareef /ZJPAS: 2017, 29(5): 112-118

However, throughout the year the sun's 1.2 Tilt Angle Equations
path and the solar altitude vary. The highest The tilt angle is time and location
point in the sun path will have largest altitude dependent, i.e., every location will have
angle value in summer on June 21th and lowest different tilt angle for different time of days of
value in winter on December 21th. The tilt a year. To calculate the tilt angle for any
angle is 90o from sun-rise and decreases until location and time over the days of year,
mid-day which reaches to its lowest value then equation from 1 to 7 can be used (Weir, 2006).
increases until 90o at sun-set (Solardata, 2017).

Where: AST: Apparent Solar Time, LST: Local standard time, LSTM: Local longitude

Where:

Where: is number of days until the required date.

Where: Lat = Latitude

1.3 Research Background of tilt angle and azimuth angle for selected
location have thus been found.
Several authors published papers to study
the effect of tilt angle on the PV panel output Abdul-wahid and Mahdi (Mahdi, 2010)
power; Salih (Salih, 2014) studded and studded the effect of changing tilt angle and the
simulated the effect of tilt angle on PV variations in the incident sunlight effect on the
performance. The simulation involved a PV amount of electrical output. Four solar panels
module tilted at 0°, 15°, 30°, 45°, and 60°. The in four different tilt angles (20o, 35o, 45o, 55o)
values of the current, voltage, and power were installed and tested for one year. Optimum tilt
measured at these positions. angle found.

Yang and Sahib (Sahib, 2007) developed a

Radhika and Suman (Suman, 2015)
new mathematical model for calculating the
calculated the effect of tilt angle and azimuth
optimum tilt angles and azimuth angles for
angle on solar output. Helioscope software
building-integrated photovoltaic (BIPV)
used to analysis the data. The optimum values
applications in Hong Kong on yearly, seasonal,
and monthly bases.
114 M. Shareef /ZJPAS: 2017, 29(5): 107-118

Kumar, Chaurasia and Singh (Saurav

Kumar, 2014) did experimental based study
that how voltage and current may be affected
as the slope of a panel gets changed for a
selected location in India. The paper shows that
at different position of solar panel has different
power & efficiency.

In this research the PV panel's tilt angle Figure 3: Arduino Mega 2560
will change between 0o to 90o degree in 1o
degree step and the five PV panel output The analogue pin A1 used to read the
voltage readings will read per second. The output voltage of the PV panel and store it into
average of the five output voltage readings is the connected computer. The analogue input of
being calculated and analyzed to find the Arduino Mega 2560 receives voltage between
impact of tilt angle on photovoltaic panel 0 to 5V which the PV panel voltage output is
output. Then the mathematical model will be more; to solve that a voltage divider used to fit
concluded. the Arduino Mega 2560 input voltage. For
accurate data collecting; at each tilt angle
2. MATERIALS AND METHODS degree change between 0o to 90o; five PV panel
output voltage reading per second taken and
For the purpose of collecting data accurate
stored in the connected computer then the
system designed and built to change the tilt average of the five readings taken.
angle from 0o to 90o degree in 1o degree step as
shown in figure 2. 3. RESULT AND DISCUSSION

The specification of the tested solar

photovoltaic panel has been shown in the
figure 4.

Figure 4: PV Panel data sheet plate

Figure 2: Designed and built system

An Arduino MEGA 2560 (figure 3) used to Before collecting the results, we have to
control the system and as data logger also find the maximum power point of the PV
(Smith, 2011). Two servo motors used to rotate panel. This can be done by using a variable
the PV panel around tilt angle axes between 0o load resistor as RL, connecting across the PV
to 90o degree. The servo motors connected to panel output terminals, and then measuring
pins 8 and 9 of the Arduino Mega 2560. both voltage and current across the RL.
115 M. Shareef /ZJPAS: 2017, 29(5): 107-118

voltage of 7.4 volts and current of 0.11

On February 22, 2017 results obtained for Amperes. At that point the power was 0.814
the PV panel maximum power point. As per watts and load resistor was 67.27 ohms. Figure
results the maxim power point occurs at 5 shows collected results.

Figure 5: PV Panel characteristics

On April 17, 2017 at 9:20AM the designed motors and five PV panel output voltages
system tested in Erbil, Kurdistan region, Iraq obtained for each single angle using the
with coordinates of latitude of 36.15° and Arduino analogue inputs as a data logger each
longitude of 44.05°. The tilt angle changed second and the average of collected calculated.
from 0° to 90° automatically by the two servo Obtained results shown in figure 6.

Figure 6: Obtained PV Panel output terminal voltage per tilt angle

116 M. Shareef /ZJPAS: 2017, 29(5): 107-118

The output power can be determined using equation 8. Obtained output power
knowing the load resistor 67.27 ohms which shown in figure 7.
connected to the PV panel output terminals and

Figure 7: PV Panel output power per tilt angle

Using equation 1 to 7 for date and time of sun's ray is perpendicular on the PV panel and
the test (April 17, 2017 at 9:20AM) the tilt it gives maximum output power.
angle can be calculated and is equal to 45°. As
seen in figure 5 the maximum output power is To know exact effect of shift of tilt angle
obtained when the tilt angle is 45° and it on the PV panel output; the percentage of out
decreased significantly when the tilt angle power drop from maximum output power
interjects from 45° because at 45° tilt angle the calculated and the results are shown in figure 8.

Figure 8: PV Panel percentage output power drop due to tilt angle shift from 45°
To get the equation of the percentage of degree the polynomial curve fitting process
output power drop with the change of tilt angle were used. For that a Matlab Polyfit function
117 M. Shareef /ZJPAS: 2017, 29(5): 107-118

(Gilat, 2011) was used and equation 9 obtained:

D = 1.41669574x10-9 A6 - 3.59548024x10-9 A5 - 5.57767010x10-6 A4 + 1.64493758x10-5 A3 -

1.724028491x10-4 A2 - 7.11435953x10-3 A +99.37322857 (9)
Where D is percentage of output power obviously seen that how much the tilt angle
drop and A is PV panel tilt angle shift in shift increases the output power drop increases
degrees. The equation 9 could be used for to and the output power decrease until it reaches
know the power drop for any PV panel for any to its minimum in -45° and 45° of tilt angle
shift in Panel tilt angle. shift.
Figure 9 shows the percentage of out power
drop from maximum output power due to shift
of tilt angle and the fitted curve with it. It's

Figure 9: PV Panel percentage output power drop and the fitted curve

4. CONCLUSION

The main conclusion of this research paper

can be described as follows:
118 M. Shareef /ZJPAS: 2017, 29(5): 107-118

1. The tilt angle orientation of the PV panel

affected its output power.
2. The maximum PV panel output power
occurred when the tilt angle was optimum
(for this work was 45°) i.e. the sun rays were
perpendicular to the PV panel.
3. The PV panel output power decreases
significantly when the tilt angle becomes far-
off from its optimum value (for this work is
45°) and the output continuously drops how
far it away from the optimum angle.
4. The mathematical model the equation of the
percentage of PV panel output power drop
with the change of tilt angle degree obtained.
This equation gives accurate results for
calculating the decrease of PV panel power
output due to tilt angle shift for any PV
panel.
REFERENCES

GILAT, A. T. 2011. MATLAB an Introduction with

Applications.
MAHDI, S. A.-W. A. E. 2010. The Effect of Tilt Angle
on the Solar Panel Output. Journal of Kerbala
University, 8.
SAHIB, H. Y. A. L. L. 2007. The Optimum Tilt Angles
and Orientations of PV Claddings for Building-
Integrated Photovoltaic (BIPV) Applications.
Journal of Solar Energy Engineering, 129.
SALIH, S. M. 2014. Effect of Tilt Angle Orientation on
Photovoltaic Module Performance. ISESCO
Journal of Science and Technology, 10.
SAURAV KUMAR, D. P. B. L. C. A. H. K. S. 2014.
Experimental Study of Optimum Tilt Angle for
Solar PV Panel in Jaipur (Rajasthan). International
Journal of Science and Research (IJSR), 3.
SMITH, A. G. 2011. Introduction to Arduino.
SOLARDATA. 2017. Available:
http://solardat.uoregon.edu/SunChartProgram.ht
ml.
SUMAN, R. A. S. K. 2015. Effect of Tilt angle and
Azimuth angle on Solar Output and Optimum Tilt
and Azimuth angle for Chandigarh, India.
International Journal of Advanced Research in
Electrical, Electronics and Instrumentation
Engineering, 4.
WEIR, J. T. A. T. 2006. Reneable Energy Resources,
USA, Taylor & Francis e-Library.

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