1. IVth International Conference on Advances in Energy Research
(ICAER2013), IIT Bombay, Mumbai
10-12 December, 2013
Influence of Dust Deposition on Photovoltaic
Panel Operating Characteristics
Authors:- Abhishek Rao, Rohitkumar Pillai, Monto Mani
and Praveen Ramamurthy
Indian Institute of Science, Bangalore

2. Background
Tropical regions are highly suitable for photovoltaic
(PV) power generation, but suffer efficiency losses
due to high cell operating temperatures and dust.
Installations in the Indian Subcontinent, the Middle
East, Saharan Africa and the south-western United
States are particularly vulnerable to dust losses.
It is essential to investigate the influence of dust
deposition on the operating characteristics of PV
systems to better quantify losses due to dust.
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3. Literature
Studies by Nahar and Gupta [1] and Said [2] show PV performance is brought down 7-20%
per month due to the accumulation of dust on the cell surfaces.
Wind tunnel experiments by Goosens and Van Kerschaever [3] indicate that high wind
speeds promote dust accumulation on photovoltaic surfaces.
Mani and Pillai [4] report that degradation in performance due to dust is worse in tropical
regions where arrays are installed with lower tilt angles.
[1] Nahar, N.M. and Gupta, J.P. (1990) Effect of dust on transmittance of glazing materials for solar collectors under arid zone conditions of India, Solar and
Wind Technology, 7, pp. 237-243.
[2] Said, S.A.M. (1990) Effect of dust accumulation on performances of thermal and photovoltaic flat-plate collectors, Applied Energy, 37(1), pp. 73-84.
[3] Goossens, D. and Van Kerschaever, E. (1999) Aeolian dust deposition on photovoltaic solar cells: the effects of wind velocity and airborne dust
concentration on cell performance, Solar Energy, 66(4), pp. 277-289.
[4] Mani, M. and Pillai, R. (2010) Impact of dust on solar photovoltaic (PV) performance: Research status, challenges and recommendations, Renewable and
Sustainable Energy Reviews, 14(9), pp. 3124-3131.
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4. Objectives
The direct impact of dust settlement on PV system performance can be gauged from the I-V
characteristics of the PV element under study, which depends on its operating conditions.
Comparing the I-V characteristics of two identical panels operating under the same ambient
parameters but with varying quantities of dust deposition isolates the influence of dust.
This study aimed at investigating the drop in photovoltaic performance attributable to dust
deposition by studying the differences in I-V curves produced from dusty and clean panels.
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5. Indoor test-bed
Two identical p-Si panels were installed side-byside parallel to the ground.
The panels were placed in a dark room with
illumination from a pair of sun-simulating
halogen lamps vertically above the panels.
One of the panels was maintained free of dust
through the simulations while the other had
dust deposited on its surface.
The intensity of the lamps could be varied.
Fig. Indoor solar simulator setup
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6. Instrumentation
I-V characteristics were plotted using MECO
9009 solar module analyzers.
The intensity of the halogen lamps was set and
measured using a TENMARS TM-207 solar
power meter.
A CENTER 352 infrared thermometer was used
to measure the temperatures on the lower
surfaces.
The I-V curves for the two panels were plotted
simultaneously while varying the incident
intensity from 200 W/m2 to 800 W/m2.
Dimensions
Module dimensions (mm x mm)
Cell dimensions (mm x mm)
Cells per module (units)
Cell area per module (m2)
675 x 485
155 x 40
36
0.2232
Electrical specifications
Maximum power (W)
Voltage at maximum power (V)
Open circuit voltage (V)
Current at maximum power (A)
Short circuit current (A)
37
17.0
21.0
2.17
2.40
Table. Panel specifications
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7. Outdoor test-bed
Two identical open-rack mounted p-Si panels
were installed side-by-side tilted at 13°.
Both panels experienced the same insolation
level, ambient temperature and wind incidence.
Cell temperatures were measured using K-type
thermocouples through BrainChild IO modules.
Readings were first taken with identical dust
depositions on both panels, and then the dust
from one of the panels was removed and
weighed, and readings were again taken.
Fig. Outdoor experimental test-bed
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8. Results
Fig. Microscopic images (at 150x) of cell surfaces on
the clean panel (L) and the dusty panel (R)
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9. Results – Indoor test-bed
Fig. Comparison of I-V characteristics at 200 W/m2
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10. Results – Indoor test-bed
Fig. Comparison of I-V characteristics at 400 W/m2
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11. Results – Indoor test-bed
Fig. Comparison of I-V characteristics at 800 W/m2
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12. Discussions – Indoor test-bed
Dust deposition does not have a significant effect on the open-circuit voltage of the panels.
However, dust has a sizable effect on the short-circuit current produced by the panels. The
clean panel consistently produced a higher current output than the dusty panel. This
difference in current outputs widened as the intensity of light incidence increased.
Output power is also affected by dust deposition due to drops in current output. A dust
deposition density of 7.155 g/m2 on the panels was seen to cause a drop in power output
by 45-55% at different intensities.
The dusty panel was noted to be operating 1-2 C higher than the clean panel. An increase
in cell operating temperature further reduces the panel conversion efficiency.
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13. Results – Outdoor test-bed
Fig. Comparison of I-V characteristics at 333 W/m2
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14. Results – Outdoor test-bed
Fig. Comparison of I-V characteristics at 525 W/m2
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15. Results – Outdoor test-bed
Fig. Comparison of I-V characteristics at 925 W/m2
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16. Discussions – Outdoor test-bed
Dust deposition does not have a significant effect on the open-circuit voltage of the panels.
Under natural sunlight, dust has only a slightly adverse effect on the short-circuit current.
The clean panel consistently produced a higher current output than the dusty panel. But
this difference in current outputs was not as dramatic as observed on the indoor test-bed.
Output power is also slightly affected by dust deposition due to slight drops in current
output. A dust deposition density of 1.4 g/m2 on the panels was seen to cause a drop in
power output by 5-6% under natural sunlight.
No significant differences in cell operating temperatures were observed due to dust
deposition on the outdoor experimental test-bed.
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17. Conclusions
This study observed that the deposition of dust on photovoltaic surfaces causes drops in
system performance and that these losses can be easily quantified using I-V curves.
It was observed that dust deposition does not significantly alter the open circuit voltage
of photovoltaic systems. However, the short circuit current is drastically affected by dust
deposition – to the tune of 30-40% in the indoor setup and 4-5% in the outdoor test-bed.
This drop in current output and the consequent drop in power output is an immense loss
of potential electrical power generation, considering the large scale of PV power plants.
I-V characteristics can be used to compare and estimate losses in PV power due to dust,
and may be used to compute the economic loss to PV power plants attributable to dust.
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18. Acknowledgments
This work is partially supported by the Robert Bosch Center for Cyber Physical Systems
(RBCCPS) at the Indian Institute of Science, Bangalore.
Further this work is partially supported in part under the US-India Partnership to Advance
Clean Energy-Research (PACE-R) for the Solar Energy Research Institute for India and the
United States (SERIIUS), funded jointly by the U.S. Department of Energy (Office of
Science, Office of Basic Energy Sciences, and Energy Efficiency and Renewable Energy,
Solar Energy Technology Program, under Subcontract DE-AC36-08GO28308 to the
National Renewable Energy Laboratory, Golden, Colorado) and the Government of India,
through the Department of Science and Technology under Subcontract IUSSTF/JCERDCSERIIUS/2012 dated 22nd Nov. 2012.
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19. IVth International Conference on Advances in Energy Research
(ICAER2013), IIT Bombay, Mumbai
Get in touch with our group ...
Prof. Monto Mani :
monto.mani@gmail.com
Abhishek Rao
:
abhishek.rao247@gmail.com
Rohitkumar Pillai
:
rohitkumar.pillai@gmail.com
Centre for Sustainable Technologies, IISc Bangalore, India.
Prof. Praveen Ramamurthy : pcramamurthy@gmail.com
Department of Materials Engineering, IISc Bangalore, India.
Thank you!