1. i
A Summer Internship report
on
Performance Analysis of 68 Watt Flexible Solar PV
Under the supervision of
Dr. K. SUDHAKAR
Assistant Professor,
Energy Centre,
Maulana Azad National Institute of Technology
Bhobal, Madhya Pradesh
At
Energy Centre,
Maulana Azad National Institute of Technology
Bhopal, Madhya Pradesh, 462051, India
Submitted by:
DHARMVEER KUMAR
(CUJ/I/2012/IEE/009)
Integrated M.Tech. (Energy Engineering)
Centre for Energy Engineering
Central Universiy of Jharkhand
Brambe, Ranchi, 535205
Jharkhand, India
June 2015

2. ii
Energy Centre
Maulana Azad National Institute of Technology
Bhopal, Madhya Pradesh, 462051
Dr. K. SUDHAKAR June 30, 2015
Energy Centre
Certificate
This is to certify that Mr. Dharmveer Kumar, Integrated M.Tech. Student at Centre for
Energy Engineering (CUJ/I/2012/IEE/009), Central University of Jharkhand, Ranchi has
completed his summer internship at Energy Centre Laboratory under my supervision during
18-May-2015 to 03-July-2015.
He had worked on the topic “Performance Analysis of 68 Watt Flexible Solar PV” and
submitted the report on the same.
Place: (Dr. K. SUDHAKAR)
Date: Supervisor

3. iii
Acknowledgement
It gives me immense pleasure to express my deepest sense of gratitude and sincere thanks to
my highly respected and esteemed guide Dr. K. SUDHAKAR, MANIT, Bhopal, for
providing me an opportunity to work under his guidance at Energy Centre, Maulana Azad
National Institute of Technology Bhopal, Madhya Pradesh.
I would like to express my sincere thanks to Mr. Akash Kumar Shukla Ph. D Research
Scholar (full time) at MANIT, Bhopal for their constant guidance, help and suggestion during
my summer internship.
I also wish to express my gratitude to Mr. Vipinraj Sugathan, Mr. Shruti Yadav, Elsa
Jhon, Lokesh Udhawani, Sibu Sam Jhon and Jay Prakash Bijarniya M. Tech. Scholars
(full time) at MANIT, Bhopal for their constant support and regular encouragement for
completing this project.
I wish to express my indebtedness to my parents as well as my family member whose
blessing and support always helped me to face the challenges ahead.
At the end I would like to express my sincere thanks to all my friends and others who helped
me directly or indirectly during my internship.
Dharmveer Kumar

4. iv
Abstract
There is need to overcome the energy crisis to provide a good standard of living for the
people. So the renewable energy sources are used extensively to harness energy from natural
source like solar and wind. Much attention is given to harnessing of solar energy as wind
energy is mostly available in coastal regions. The growth and development in solar PV
technologies increasing rapidly due to technological improvement, cost reductions in
materials and governments support for renewable energy based electricity production. Thin-
film flexible photovoltaics are paving the way to low-cost electricity. Organic, inorganic and
organic-inorganic solar cells are deposited over flexible substrates by high-throughput (often
roll-to-roll printing) technologies to afford lightweight, economic solar modules that can be
integrated into, not installed on, various surfaces. Current conversion efficiencies under
standard conditions are in the 3 – 15 %range, but in real applications the overall productivity
is high. These new photovoltaic technologies are ready to provide cheap, clean electricity to
the billions of people who lack access to the grid as well as to energy-eager companies and
families in the developed world facing the increasing costs of electricity generated using
fossil fuel resources. This paper includes the performance analysis of a Thin-film flexible 68
Watt solar PV on Roof-top and Facade condition in a hazy day.

5. v
List of Figures
Figure 1: Source of electricity generation in India by installed capacity.
Figure 2: Plastic solar cells.
Figure 3: New flexible solar modules.
Figure 4: Thin-film PV modules laminated together with polyolefin membranes.
Figure 5: Scheme of triple-junction structure containing amorphous silicon.
Figure 6: United Solar Ovonic flexible PV.
Figure 7: Open-circuit voltage.
Figure 8: Short-circuit current.
Figure 9: Fill factor.
Figure: 10 Flexible solar PV – Roof-top.
Figure: 11 Flexible solar PV – Facade.
Figure: 12 Solar power meter.
Figure: 13 Voltmeter.
Figure: 14 Ammeter.
Figure: 15 Rheostat.
Figure: 16 Environment Meter.
Figure: 17 Infrared Thermometer.
Figure: 18 Multimeter.
Figure: 19 Thermometer.
Figure: 20 Circuit arrangements.

6. vi
List of Tables
Table: 1 Parameters for calculating efficiency.
Table: 2 Specification of 68 W solar PV.
Table: 3 Measured Energy and exergy values.
Table: 4 Table for results.

7. vii
Table of Contents
Title Page..................................................................................................i
Certificate.................................................................................................ii
Acknowledgement....................................................................................iii
Abstract....................................................................................................iv
List of Figures...........................................................................................v
List of Tables............................................................................................vi
Chapter 1: Introduction.............................................................................1
Chapter 2: Why flexible module................................................................2
Chapter 3: Inorganic thin films: Flexible a-Si Module................................3
Chapter 4: Performance analysis................................................................5
4.1 Energy efficiency.............................................................................5
4.1.1 Open-circuit voltage................................................................6
4.1.2 Short-circuit current................................................................6
4.1.3 Solar cell efficiency..................................................................7
4.1.4 Fill factor.................................................................................7
4.2 Exergy efficiency..............................................................................8
Chapter 5: Instruments used.......................................................................8
5.1 Flexible solar PV..............................................................................8
5.2 Solar power meter............................................................................9
5.3 Voltmeter.........................................................................................9
5.4 Ammeter..........................................................................................10
5.5 Rheostat...........................................................................................10
5.6 Environment meter...........................................................................10
5.7 Infrared thermometer........................................................................10
5.8 Multimeter........................................................................................10
5.9 Thermometer....................................................................................10
Chapter 6: Methodology..............................................................................11
Chapter 7: Circuit arrangement....................................................................11
Chapter 8: Calculation.................................................................................12
Chapter 9: Results and Graph.....................................................................12
Chapter 10: Conclusion...............................................................................14
Chapter 11: References................................................................................14

8. 1
Chapter 1: Introduction
The electron, it has been said, is the ultimate currency of modern society. Electricity indeed,
being silent, clean, easily transported and converted into work, is the most widely used form
of energy. Yet, besides a 2% share from nuclear fission [13]
, we mainly produce electricity by
burning hydrocarbons and sadly enough, much cheaper coal. For example, more than half
(59%) of installed capacity use coal for electricity production in India [13]
(Figure 1). Over the
next decade, China alone will need to add some 25 GW of new capacity each year to meet
demand, equivalent to one large coal power station every week. Unfortunately, coal contains
mercury and along with the production of immense amounts of climate-altering CO2, its
combustion is causing pollution of the oceans and of the food chain. To abate emissions and
stop climate change, the biggest challenge of our epoch is to get electricity directly from sun
[3]
.
Figure 1: Source of electricity generation in India by installed capacity.
The growth and development in solar PV technology is increasing rapidly due to
technological improvement, cost reduction in materials and government support for
renewable energy based electricity production [1]
. The solar panels are installed to harness
energy from the sun. Generally the panels are installed on the roof-top of the buildings either
grid connected or standalone. Now a days with the advancement in technology, several new
types of solar panels are introduced in the market. They are flexible PV, transparent PV, dye-
sensitized solar cell etc. The flexible PV can be rolled and can be installed on any surface
either linear or curved. This has made installation easier as it require no extra area for
installation. It can be installed on the building top-roof or on the wall of the buildings. It also
helps in decorating the buildings. The modules are fabricated for high efficiency, multiple
junction a-Si alloy solar cell [2]
. There are several companies manufacturing flexible PV like
UNI-SOLAR, Microlink etc [4]
.

9. 2
Chapter 2: Why flexible solar module
Like the internet was not invented by taxing the telegraph [5]
, so cheap and abundant
electricity from the sun will not be obtained by adding taxation on carbon dioxide emissions,
but rather by inventing new, cheap solar modules capable of converting light into electrical
power with more than 50% efficiency instead of the current 20% or so. These modules,
furthermore, will increasingly be flexible and lightweight to reliably produce electricity with
little maintenance while being integrated into existing buildings, fabrics, tents, sails, glass,
and all sort of surfaces. By doing so, the price of solar energy will be lowered to the level of
coal-generated electricity so that people living in huge emerging countries will rapidly adopt
solar energy for their economic development.
Once price of good news is that the first such commercial modules are now ready and
commercially available. Their efficiency of 3-15% under standard conditions is still low, yet
the price of solar electricity generated through thin-film second-generation PV technologies
is considerably lower than that of traditional silicon-based panels. In perspective, much
higher conversion efficiencies may be achieved with the introduction of third-generation PV
technologies [6]
such as those that companies like QuantaSol [7]
are about to launch on the
market. In general, the technology trend is that of the so-called plastic electronics, namely to
print circuits and devices on flexible substrates at room temperature (low energy) and with
roll-to-roll processes (high throughput). For example, flexible displays that use organic light-
emitting diodes (OLEDs) applied in thin layers over plastic finally make electronic viewing
more convenient than reading on paper. The thinness, lightness and robustness enabled by the
flexibility of OLED-based displays creates digital reader products that are as comfortable and
natural to read as paper [8]
. In this turn, a flexible solar Module (Figure 2) of the type
described below might easily power the OLED device enabling unlimited access to thousands
of pages.
Figure 2: Plastic solar cells, such that on the left which is entirely organic or that on the right which
uses amorphous Si, are lightweight are ideally suited for customised integrated solutions.
Flexible solar PV devices offer a convenient alternative energy source for indoor and
outdoor applications. Besides being flexible and thus easily integrated with elements of
various shapes and sizes of the design of innovative energy-generating products, these
unbreakable flexible modules are lightweight and suitable for applications where weight is
important, while they offer a much faster payback then products based on conventional PVs

10. 3
[9]
. Typically, the photovoltaic material is printed on a roll of conductive substrate (which
may be conductive plastic) [10]
making highly efficient use of the photoactive material. As a
result, this simple, highest-yield technique in air is capital-efficient and eliminates the need
for costly vacuum-deposition techniques originally used to fabricate thin-film solar cells. The
photovoltaic functionality gets integrated at low cost in existing structures, printing rolls of
the PV material anywhere, from windows to roofs, through external and internal walls,
replacing the traditional installation approach with and integration strategy (figure 3).
Figure 3: New flexible solar modules are integrated, rather than installed, into existing or new
buildings (picture adapted from konarka).
Chapter 3: Inorganic thin films: Flexible a-Si Module
Following the introduction in 1997 of triple-junction modules, which provide relatively high
levels of efficiency and stability (stabilized aperture area cell efficiency of 8.0-8.5 %) [11]
, the
most successful flexible PV modules developed thus far use amorphous silicon (a-Si) thin-
film technology (figure 4). In a triple-junction cell, cells of different band gaps are stacked
together (Figure 5). The top cell, which captures the blue photons, uses an a-Si alloy with an
optical gap of about 1.8 eV for the intrinsic (i) layer. The i layer for the middle cell is an
amorphous silicon-germanium (a-SiGe) alloy that contains about 10-15 % Ge and has an
optical gap of about 1.6 eV, which is ideally suited for absorbing green photons. The bottom
cell captures the red and infrared photons and uses an i layer of a-SiGe alloy with an optical
gap of about 1.4 eV. Light that is not absorbed in the cells gets reflected from the
aluminium/zinc oxide (Al/ZnO) black reflector, which is textured to facilitate light trapping.

11. 4
Figure 4: Thin-film PV modules laminated together with polyolefin membranes, which act as a
waterproofing system. Roofing membranes are joined by means of hot air welding equipment
normally used for the construction of flat roofs.
The resulting thin-film photovoltaic product has the ability to capture a greater
percentage of the incident light energy, which is a key to a higher energy output at lower
irradiation levels and under diffused light. As an example, the overall annual energy yield of
the thermally insulated a-Si plant over the roof of a school in Switzerland (figure 4) was
almost comparable to that of a 200
tilted open-rack c-Si power plant, despite the lower
irradiance and higher reflection losses associated with the latter [12]
.
Figure 5: Scheme of triple-junction structure containing amorphous silicon (reported from
http://www.uni-solar.com, with permission).
Usually, the cell is deposited using a vapour-deposition process at low temperatures;
the energy payback time is therefore much shorter than that conventional technology. The
roll-to-roll process utilizes a flexible, stainless steel substrate (figure 6). Once the solar cell
material has been fitted with suitable electrodes, the cells are encapsulated in UV-stabilized,
weather-resistant polymers. In a high-volume manufacturing plant operated by United Solar
Ovonic (Michigan, USA), solar cells are deposited on rolls of stainless steel. Rolls of
stainless steel (2500 m long,36 cm wide, and 125 μm thick) move in a continuous manner in
four machines to complete the fabrication of the solar cell. A wash machine washes the web
one roll at a time; a back-reflector machine deposits the back reflector by sputtering Al and
ZnO on the washed rolls; an amorphous silicon alloy processor deposits the layer of a-Si and
a-SiGe alloy; and finally an anti-reflection coating machine deposits indium tin oxide (ITO)
on top of the rolls. The coated web is next processed to make a variety of lightweight,
flexible and robust products.

12. 5
Figure 6: United Solar Ovonic flexible PV laminated is made of a-Si triple-deposited over steel (left),
while thin films of Flexcell are deposited roll-to-roll over plastic substrates (right). (Reproduced from
http://www.uni-solar.com and http://www.flexcell.ch, with permission.)
Chapter 4: Performance analysis
The analysis usually includes the efficiency of the solar panel that it can reach during its
operation. The parameters for calculating efficiency are given below (Table 1):
Name Symbol
Ambient Temperature TA (0
C)
Wind Velocity VW (m/s)
Relative Humidity HR (%)
Solar Intensity IS (W/m2
)
Module Temperature TM (0
C)
Open Circuit Voltage VOC (V)
Maximum Voltage Vm (V)
Short Circuit Current ISC (A)
Maximum Current Im (A)
Maximum Power Pm (W)
Energy Efficiency ղ
Fill Factor FF
Exergy Efficiency Ψ
Module Area AM (m2
)
Exergy Efficiency Ψ
Exergy of system
Convective heat transfer coefficient hca

13. 6
4.1 Energy Efficiency
4.1.1 Open Circuit Voltage
The open-circuit voltage, VOC, is the maximum voltage available from a solar cell, and this
occurs at zero current. The open-circuit voltage corresponds to the amount of forward bias on
the solar cell due to the bias of the solar cell junction with the light-generated current. The
open-circuit voltage is shown on the IV curve below, figure-7.
Figure 7: Open-circuit voltage.
4.1.2 Short Circuit Current
The short-circuit current is the current through the solar cell when the voltage across
the solar cell is zero (i.e., when the solar cell is short circuited). Usually written as ISC, the
short-circuit current is shown on the IV curve below, figure-8. The short-circuit current is due
to the generation and collection of light-generated carriers. For an ideal solar cell at most
moderate resistive loss mechanisms, the short-circuit current and the light-generated current
are identical. Therefore, the short-circuit current is the largest current which may be drawn
from the solar cell.
Figure 8: Short-circuit current.

14. 7
4.1.3 Solar cell efficiency
Solar cell efficiency is the ratio of the electrical output of a solar cell to the incident
energy in the form of sunlight. The energy conversion efficiency (ղ) of a solar cell is the
percentage of the solar energy to which the cell is exposed that is converted into electrical
energy.
The energy efficiency of a solar panel can be calculated using the relation
ղ =
𝑉 𝑚 𝐼 𝑚
𝐼 𝑆 𝐴 𝑀
(1)
or ղ =
𝑃 𝑚
𝐼 𝑆 𝐴 𝑀
{𝑃𝑚 = 𝑉𝑚 𝐼 𝑚} (2)
4.1.4 Fill Factor
At both of these operating points, the power from the solar cell is zero. The "fill
factor", is a parameter which, in conjunction with Voc and Isc, determines the maximum
power from a solar cell. The FF is defined as the ratio of the maximum power from the solar
cell to the product of Voc and Isc. Graphically, the FF is a measure of the "squareness" of the
solar cell and is also the area of the largest rectangle which will fit in the IV curve. The FF is
illustrated below, figure-9.
Figure 9: Fill factor. Graph of cell output current (red line) and power (blue line) as function
of voltage. Also shown are the short-circuit current (ISC) and open-circuit voltage (VOC)
points, as well as the maximum power point (Vmp¸Imp).
FF =
𝐼 𝑚 𝑉 𝑚
𝐼 𝑆𝐶 𝑉 𝑂𝐶
(3)

15. 8
4.2 Exergy efficiency
Exergy efficiency (also known as the second-law efficiency or rational efficiency) computes
the efficiency of a process taking the second law of thermodynamics into account.
The exergy efficiency of a solar panel can be calculated using the relations [14-17]
given
below:
Ψ = (4)
𝐸 𝑋
̇ = 𝑉𝑚 𝐼 𝑚 − [1 − (
𝑇 𝐴
𝑇 𝑀
)] × 𝑄̇ (5)
𝑄̇ = ℎ 𝑎𝑐 𝐴 𝑀(𝑇 𝑀 − 𝑇𝐴) (6)
ℎ 𝑐𝑎 = 5.7 + 3.8𝑉 𝑊 (7)
EX
̇ Solar = [1 − (
TA
TM
)] × ISAM (8)
Chapter 5: Instruments used
5.1 Flexible Solar PV (68 W)
It is a product of UNI-SOLAR Company, figure-10 and figure-11.
Table: 1. Specification of 68W flexible solar PV (Table 2).
(At STC, 1000 W/m2
, AM 1.5 and 250
C cell temperature)
Parameters Value
Maximum Power (Pmax) 68 W
Voltage at Pmax (Vmp) 16.5 V
Current at Pmax (Imp) 4.1 A
Short-circuit Current (ISC) 5.1 A
Open-circuit Voltage (VOC) 23.1 V
Maximum Series Fuse Rating 8 A
Dimensions 2849 × 394 × 4 mm
Weight 3.9 Kg

16. 9
Figure: 10 Flexible solar PV – Roof-top Figure: 11 Flexible solar PV - Facade
5.2 Solar Power meter
This instrument is used to measure the solar irradiance which is the amount of light falling on
the surface of the PV. This gives us the input power per unit are for the panel, which on
multiplying with area of the module gives the input power. Figure – 5 shows a solar power
meter.
Figure: 12 Solar power meter
5.3 Voltmeter
This instrument is used to measure the open circuit voltage (VOC). It is of range 0-100 V.

17. 10
5.4 Ammeter
This instrument is used to measure the short-circuit current. It is of range 0-2.5 A. Figure 14
shows an ammeter.
5.5 Rheostat
This instrument is used to produce variable resistance during the measurement of Vm and Im.
Figure-15 shows a Rheostat.
5.6 Environment Meter
This instrument has multipurpose use. It is used to measure relative humidity and wind-
speed. Figure-16 shows an Environment meter.
5.7 Infrared Thermometer
This instrument is used to measure the module temperature using infrared light. Figure-17
shows a infrared thermometer. It has a range of wavelength 630-670 nm.
Figure: 15 Figure: 16 Figure: 17
5.8 Multimeter
This instrument is used to measure voltage and current at the output of the module. It has a
range of 0-1000 V and 0-10 A. Figure-18 shows a multimeter.
5.9 Thermometer
This instrument is used to measure the ambient temperature. Figure-19 shows a thermometer.

18. 11
Chapter 6: Methodology
The panel is placed at two different positions one is at facade and other is at top-roof. The
flexible PV is kept at an angle 23.250
with reference to northern hemisphere for top-roof
placements so that the panel always faces the sun.
For facade placements, the panel can be placed on the window or door at a vertical
position. The panel is connected to a rheostat having variable resistance across which the
voltage reading is taken by a voltmeter and current reading is taken by an ammeter. This will
give an open-circuit voltage and short-circuit current as output, which in turn give the output
power. The input is taken as the amount of light falling on the panel surface. It is measured
by the solar power meter which gives the solar irradiance when multiplied with the surface
are of the panel gives the input power. The efficiency is given as the ratio of power output to
the input power of the panel. The efficiency is determined for both roof-top and facade
condition.
Chapter 7: Circuit arrangement
For calculating the maximum voltage (Vm) and maximum current (Im) we connect a voltmeter
in parallel, an ammeter in series with the flexible panel and then a variable rheostat in
parallel. To measure the Vm and Im we take several reading of voltage and current by varying
the rheostat. Now the voltage and current corresponding to the maximum power gives the
maximum voltage (Vm) and (Im).
Circuit arrangement for calculating Vm and Im is given below (figure-20).
Figure: 20 Circuit arrangements.

19. 12
Chapter 8: Calculation
The efficiency and other Parameters of flexible PV for roof-top and facade condition is
calculated below in the table 3.
Table: 3. Energy and Exergy parameters measured during the experiment.
Chapter 9: Results and Graph
Table for Result (Table 4):
Parameters Value
Overall Energy efficiency in roof-top condition 0.014696
Overall Energy efficiency in facade condition 0.038745
Overall Exergy efficiency in roof-top condition 1.2205
Overall Exergy efficiency in facade condition 4.8829

20. 13
Graph 1 – 4 represent the roof-top condition of the flexible panel.
Graph 6 – 8 represents the facade condition of the flexible panel.

21. 14
Chapter 10: Conclusion
This study presents the performance analysis of thin film flexible PV module in the month of
June in hazy day condition at Maulana Azad National Institute of Technology, Bhopal, India.
In the performance analysis I found that the energy and exergy efficiency is higher in facade
condition as compared to the roof-top condition.
Chapter 11: References
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technology: research and development. Renew Sust Energ Rev 2013; 20: 443-61.
[2] Izu M, Ovshinsky HC, Whelan K, Fatalski L, Ovshinsky SR. Lightweight flexible rooftop
PV module. Photovoltaic energy conversion 1994; 1: 990-93.
[3] Lewis NS. Science 2007; 315: 798.
[4] Scheiman D, Jenkins P, Walters R, Trautz K, Hoheiselr R, Tatavarti R, Chan R,
Miyamoto H, Adams J, Elarde V, Stender C, Hains A, McPheeters C, Youtsey C, Pan N,
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[5] Nordhuas T, Shellenberger M. Break through: From the death of environmentalism to the
politics of possibility. Houghton Mifflin, New York 2007.
[6] Green MA. Third generation photovoltaics. Springer, New York 2003.
[7] QuantaSol is a spin-off from imperial college London: http://www.quantasol.com.
[8] The first manufacturing facility targeted at flexible active-matrix display modules was
built in 2008 by plastic logic (Dersden, Germany) with an initial capacity of more than
1000000 display modules per year: http://www.plasticlogic.com.
[9] See, for instance, Flexcell’s products: http://www.flexcell.ch.
[10] For an account of the discovery of conductive polymers, see:
http://nobelprize.org/nobel_prizes/chemistry/laureates/2000/heeger-lecture.html.
[11] Gregg A, Blieden R, Chang H, Ng. Performance analysis of large scale, amorphous
silicon photovoltaic power systems.31st
Institute of electrical and electronics engineers,
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2005: 3-7.
[12] Pola I, Chianese A. Bernasconi. Sol. Energy 2007; 81: 1144.
[13] Electricity sector in India: https://en.wikipedia.org/wiki/Electricity_sector_in_India.

22. 15
[14] Sahin AD, Dincer I, Rosen MA. Thermodynamic analysis of solar photovoltaic cell
systems. Sol Energy Mater Sol Cells 2007; 91: 153-59.
[15] Joshi AS, Dincer I, Raddy BV. Thermodynamic assessment of photovoltaic systems. Sol
Energy 2009; 83: 1139-49.
[16] Pandey AK. Exergy analysis and exergoeconomic evaluation of renewable energy
conversion systems. Ph.D. Thesis, School of Energy Management, Shri Mata Vashno Devi
University, Katra, India 2013.
[17] Pandey AK, Tyagi VV, Tyagi SK. Exergic analysis and parametric study of multi-
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