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1 Copyright © 2011 by ASME
Proceedings of the 5th International Conference on Energy Sustainability ESFuelCell2011
August 7-10, 2011, Washington, DC, USA
ESFuelCell2011-54625
TESTING PERFORMANCE, WEATHERING AND AGING OF PHOTOVOLTAIC MODULES
Michele Trancossi Università di Modena e Reggio Emilia - ITIS Nobili
Member of ASTM Committee E44 on Solar, Geothermal and Other Alternative Energy Sources Reggio Emilia, RE, Italy
ABSTRACT This paper presents the ASTM WK22010 proposed
standard on testing of photovoltaic modules. It aims to become
a general framework that defines objective parameters
regarding output production and lifecycle of modules and
includes: - quantifying the PV module performance decay from
the global effects of extended outdoor weather exposure and
induced fatigue stress; - determine the mechanical resistance of
modules to weathering from exposure to real outdoor or
artificially created conditions, including extreme weather
events; - determine the mechanical resistance and decay of
optical characteristics of glasses from exposure to real outdoor
or artificially created conditions, including extreme weather
events; - determine the effective output production of modules
and the resulting decay, during the expected module lifetime in
real operating conditions and/or predefined artificial weather
conditions; in order to predict performance in different real
weather conditions from test result parameters.
INTRODUCTION The testing activity and methodologies of photovoltaic
modules is a problematic field of applied research. It is due to
climatic reasons because photovoltaic modules performances
and lifetime duration is directly affected by climatic operative
conditions.
Different standards can apply to photovoltaic modules
performances but they often presents an intrinsic limit related to
the specific nature of prescribed tests and difficulties in
comparison of results.
Starting from the present standardization scenario, this
paper aims to present an analysis derived from the personal
experience of the author. It aims to discuss the limit of the
present standardization and to make some hypothesis about the
future possibility of more effective and scientifically validated
testing methodologies on PV modules.
The exigency of a well designed testing model which can
produce comparable data and can help to increase the
excellence of industrial production, and can help final users in
their commercial choices, regarding PV modules is an
important argument and field of research, both for industry and
for academia, because it can be a field for an enhanced
cooperation to define better testing methodologies.
It is not positive to define new bureaucratic procedures but
well defined tested procedures which can be positive both for
financial institutions and specific photovoltaic modules market.
THE PRESENT STANDARDIZATION SCENARIO
IEC and IECEE standards The presentation of Liang at SEMI International Standards
Workshop [1] describes the present standardization scenario
and its possible evolutions.
He correctly focused his attention on IEC TC82 Standards,
which assume a special importance because they are accepted
world wide and they are needed for any commercial module.
In particular two standards are used for flat plate PV
module performance characterization. They are both developed
by IEC TC82 WG2:
− IEC 61215 Ed.2: 2005-04 Crystalline silicon terrestrial
photovoltaic (PV) modules – Design qualification and
type approval Ed.1: 1993-04, Ed.3 is under discussion
− IEC 61646 Ed.2: 2008-04 Thin-film terrestrial
photovoltaic (PV) modules – Design qualification and
type approval, Ed.1: 1996-11, Ed.3 is under
discussion.
They focus on how PV modules have to be built and
equipped.
2 Copyright © 2011 by ASME
Following IEC standards are widely used for flat plate PV
module safety:
− IEC 61730-1 Ed.1: 2004-10 Photovoltaic (PV) module
safety qualification - Part 1: Requirements for
construction
− IEC 61730-2 Ed.1: 2004-10 Photovoltaic (PV) module
safety qualification - Part 2: Requirements for testing
Both Ed.2s are under discussion.
Liang in this presentation also traced the objective related
to the migration from IEC to IECEE, which are connected to
define a common worldwide standardization platform for
electrical devices:
IEC achieved a really important target: one test and one
international certificate; but still one or more marks are needed.
The ideal target if IECEE will be: one test, one certification,
one mark.
ANSI Standards Another important standard, not cited by Liang, is the
ANSI/UL 1703-2004, which prescribes general testing
procedures, which must be passed by a module prior to be
distributed on the market. Laboratories tests are prescribed to
ensure that the modules are compliant with this and other
related standards.
Intertek presents the main reasons of testing fails ANSI/UL
1703-2004 in a well known whitepaper [2]. It says: “When a
product does not meet all of the requirements of the standard,
the manufacturer must make appropriate corrections and
repeat the testing process before receiving certification for
market access…In the testing of PV modules, a large
proportion of products do not receive certification based on
their first testing cycle.”
The Intertek document analyses the most common reasons
of PV modules certification failures and address specific , and
explains some of the reasons why they occur. PV module
manufacturers can use this information to detect and avoid
errors in the design and manufacturing stages, thereby saving
considerable time, cost and frustration.
ASTM activity An important activity has also been performed by ASTM
Committee E44 on Solar, Geothermal and Other Alternative
Energy Sources, and in particular by Committee E44.09 on
Photovoltaic Electric Power Conversion. ASTM E44.09
activity is quite large and important even on arguments related
to the object of this paper. ASTM has been produced many
active standards [8-26].
Also some new and very innovative standards have being
discussed under the jurisdiction of ASTM E44.09:
− WK22009 New Test Method for Reporting
Photovoltaic Non-Concentrator System Performance;
− WK22010 New Guide for Testing Performances,
Weathering and Aging of Photovoltaic Modules;
− WK25362 New Practice for Accelerated Life Testing
of Photovoltaic Modules.
National standards Other standards are approved or under discussion in
different countries worldwide for better PV modules testing
both in terms of performance characterization, safety, and
lifecycle prediction and they are not cited in this paper
presented in the states and regarding mostly US
standardization.
FLASH TEST Most manufacturers classify their modules using a simple
testing procedure called the “flash test”, which is defined in the
standards cited before [3, 4].
This test consists in a short time exposure of a module,
from 1ms to 30 ms bright, to a bright flash of light from a
xenon-arc lamp of 100 mW/cm2. The output is collected by a
computer and the data is compared to a reference solar module.
The reference module has its power output calibrated to
standard solar irradiation [10]. The results of the flash test are
compared to the specifications of the PV module datasheet and
the numbers printed on the PV module’s back.
During Flash test module parameters are measured at
standard test conditions (STC). STC specifies a temperature of
25 °C and an irradiance of 1000 W/m2 with an air mass 1.5
(AM1.5) spectrum. These correspond to the irradiance and
spectrum of sunlight incident on a clear day upon a sun-facing
37°-tilted surface with the sun at an angle of 41.81° above the
horizon.
This ideal condition aims to represent approximately solar
noon conditions near equinoxes at a latitude about 40, with
surface of the cell aimed directly at the sun.
The use of STC conditions is due to the importance of
temperature on the PV module performance. As the temperature
of a module increases two things happen:
1. the voltage output decreases;
2. the current output of each cell increases slower.
This standard has not any effective relation with effective
operating conditions.
RESULTS OF THE FLASH TEST With the use of the flash test, the following parameters are
tested. All measurements are made at the module’s electrical
terminals mounted on the module’s back, using highly accurate
instruments.
PV Modules are rated at two voltage levels:
1. VOC (V): open-circuit voltage, measured with the
module disconnected from any load;
2. VMP (V): voltage at maximum power point, measured
at the voltage at which the module puts out the most
power.
They are also rated in terms of current intensity at two
important levels:
1. ISC (A): short-circuit current, the amount of current
that the PV module supplies into a dead short;
2. Imp (A), Current at maximum power point, intensity of
current delivered by the module at its maximum power
point.
3 Copyright © 2011 by ASME
It is also possible to define:
1. Pm (W): Maximum Power and Maximum Power Point.
In which two measures are performed:
- power is equal to Amperes times Volts
P=IE [W] = [A V].
- Specific point on its power curve where the product
IE yields the greatest power.
2. FF (%), Fill Factor: defined as the maximum power
produced (at MPP) divided by the product of Isc and
Voc.
Some considerations can be expressed both on PM and FF.
Pm is the Maximum Power Point, and the module’s power
output is rated at this point’s voltage and current. To calculate
maximum power point, the flash test takes data over the entire
range of voltage and current and in this way the wattage for
each current and tension data point can be calculated. By doing
this it is possible to plot current versus tension graphs.
The Fill Factor will always be less than 1. The use of the
fill factor instead of conversion efficiency is caused by the
obvious difficulties connected to conversion efficiency
calculation using short times.
FLASH TEST ADVANTAGES AND LIMITS Every manufacturer should provide the flash test of all
solar panels delivered. It can be also performed by final
customers to verify if all quality criteria are met.
This test has a great advantage f compared to any other
possible testing method, but present many problems related to
his scientific validity. It is a comparison between the
performances of a single module to a reference module of
comparable characteristics. It can be certainly a good test to
verify by comparison with an ideal reference module of the
same type subject to an ideal light. It gives an instantaneous
response about the potential performances of a PV module in
fast transient conditions.
In can be certainly useful for a correct string balancing,
because it is well known that modules with results of flash test
of the same order works better together. It can also give a
comparative information on same model products.
They are certainly important information, but the not solve
the problems of a correct classifications of modules based on
common parameters such as nominal performances, aging
behavior, stress and failure modes.
VISUAL INSPECTION AND COMMON DEFECTS OF PV MODULES
Some defects are common results of PV when testing solar
panels:
1. Scratches on frame/glass
2. Excessive or uneven glue marks
3. Glue marks on glass
4. Gap between frame and glass due to poor sealing
5. Delamination of EVA degrading the optical coupling
between the cell and the front glass;
6. Lower output than stated in data sheet (we require
positive tolerance on each solar panel)
7. Lower FF than stated in requirements
In the case of producers with a well tested quality system
identified defective solar panels straight after production. They
can be declassed (2nd, 3
rd choice), replaced or repaired. This is
the only approach that will ensure that your solar panels will
perform at 100% and are perfect in appearance as well. This
approach helps solar panel system installers to prevent time
consuming problems when defective solar panels are identified
after arrival. The main problem is that some solar
manufacturers continue to fail in quality exam and choice of
modules before shipping.
UNSOLVED PROBLEMS IN PV EVALUATION The cited standards can solve some industrial problems and
many safety related ones, but they are really far from a general
vision of the photovoltaic modules characterization. This is a
really hard to solve problem because too many parameters
influence both testing conditions and results. It is true both for
artificial light tests and for natural sunlight exposure tests.
In the Strategic Planning Session 2009 of ASTM E44 [30]
the author obtained the inclusion in the list of standard needs
the performance testing of PV modules, using the following
definition: “Solid, rigid and well tested method in order to
determinate the main characteristic of different panels, both in
terms of performance and electric circuit characteristics”.
Some month before an independent standard project had
started to encourage discussion on the still opened problem of
PV modules testing for different exigencies. It is the ASTM
WK 22010 “New Guide for Testing Performances, Weathering
and Aging of Photovoltaic Modules”.
The primary exigency of this standard has been
synthesized by some arising limit observed in further activity of
the ASTM committee.
The author expressed, during his activity in ASTM E44.09
sub-committee a negative vote [31] on a proposed test method
to define the performances of PV modules. A citation of this
negative can be useful to understand better the main problems
related to natural sunlight exposure testing:
“By considering paragraphs 6.4 and 6.5, there appears
many problems concerning climatic data evaluation:
− In 6.4 it is written that if temperature does not reach the
standard testing temperature it can be affirmed that
temperature is different. This means that it is possible to
test the modules in every desired condition, without any
comparative analysis of results.
− In 6.5 it is stated: “A different reporting wind speed may be
selected from local meteorological data, or the effects of
wind speed may be neglected entirely by fixing the data to
0 m/s”. This means that by the faculty of imposing a wind
velocity at 0 m/s value can produce effect on increasing the
values of producibility by ignoring the effects of convection
on panel heat dissipation during the production top.
Those effects have negative effect not only in terms of lack
of generality of produced results but can produce a general
4 Copyright © 2011 by ASME
anarchy about testing conditions and can have negative effects
in order to produce an effective evaluation about PV plants
productivity, with negative effects on the banking system by
giving an idealized producibility of modules and not a realistic
and comparable one.
All data during tests must be declared and if exists
formulas to evaluate the productivity in any other location
different than the testing one must be provided also to
guarantee a correct evaluation of the results.
The suggested methodology does not take in account some
specific scientific evidences: the well known the importance of
climatic and altitude factors on PV modules production.
By these considerations it can be deduced that it is not
possible to define a natural exposure testing procedure without
declaring exactly the testing conditions. If they are not declared
or if they can impose equal to a standard value, there will not
be any scientific validity of tests.
Even if this problem is really far from producers and
resellers of PV equipment, it can conduce to many future
problems especially for producers and resellers, because it can
be easy to destroy the declared specifications of the products in
any court of justice. It can be said that actual standardization
prescribes only simple practices for PV modules evaluation.
This idea has been evidenced in another negative by Burns
[32]:
“Examples of practices include, but are not limited to: …
assessment…" and a "Test Method, n— a definitive procedure
that produces a test result. A precision and bias statement shall
be reported at the end of a test method." In that this standard
does not describe a 'definitive procedure' nor produce a test
results, hence it is a Practice.”
This definition is directly related to the ASTM’s definition
of practice and of test method:
“Practice, is a definitive set of instructions for performing
one or more specific operations that does not produce a test
result”.
STRESS AND AGING TESTS The above cited negative vote comments by David Burns
also explain one of the key problems related to testing
methodologies about PV modules:
“This standard is based on the assumption that total UV
exposure (dosage) is the sole driving force for degradation of
PV properties. This assumes the Law of Reciprocity is
universally valid. It is well established in the technical
literature that universal Reciprocity is a gross simplification
(see Hardcastle's 2006 ATCAE Conference paper "A
Characterization of the Relationship between Light Intensity
and Degradation Rate for Weathering Durability"). It is also
well established that there are significant differences between
natural outdoor and machine exposure results – unless
significantly greater attention is paid to characterizing the
response of the specific materials/systems under test than is
provided for in this Practice. Sec. 5.4 states of this document
states "…xenon-arc exposure … may not be equivalent to an
outdoor exposure conducted to…" the same total UV exposure.
Well, if they are not equivalent, then why does this standard
imply they will be? This is sufficient justification to split this
into multiple practices.”
After this negative, during the 2010 E44 meeting [7],
Burns extended the exigency of a well defined testing
methodology also for stress resistance of PV modules.
MOST IMPORTANT PARAMETERS INFLUENCING PV MODULE BEHAVIOUR
Classification of parameters governing the PV process
A PV module is a system designed to transform, under
certain environmental and climatic dynamic conditions, an
external input (solar radiation) into electric energy.
This definition intended to evidence the factors which
govern the PV transformation and PV modules. They can vary
under some well known parameters. They are both external and
internal. These two classes can be defined as follows.
External parameters can be defined as the external factors
which presents an indirect effect on PV module nominal
performances, lifecycle performance degradation and duration.
These parameters are directly connected with
environmental conditions in which the modules are tested or in
which they work. Any operative condition can have direct
effects on the modules, both in terms of electrical productivity
and in terms lifecycle performance degradation.
Internal parameters are connected on the way the module is
realized, adopted materials and installed components. They can
be defined as the way in which module components and
materials interact when the module is exposed to external
parameters.
These definitions can be useful to classify the real
parameters affecting the PV transformations. It is also evident
that internal parameters are conditioned deeply by external
ones. In particular a very general classification can be the
following:
Main external parameters are air temperature, wind speed,
solar radiation, atmospheric filter, and atmospheric deposition
on the modules.
Main internal parameters are equilibrium temperature;
cells, connections, glass and EVA, other electrical components
quality and aging.
Combination of these parameters The results of the combination of internal and external
parameters are the electricity produced and how it can vary as a
function of time, at least in terms of average values. It is
evident that both parameters will concur to this result.
Other fundamental results are the life cycle duration
estimation and the failure modes analysis on different operative
conditions.
The present standardization about photovoltaic modules
performance lacks in terms of evaluation of the external
parameters, especially during performance testing. A correct
standardization policy needs to improve a more rigorous and
5 Copyright © 2011 by ASME
effective testing policy for photovoltaic modules. It can provide
a correct response to an effective quality exigency of the
market, which can be reached only in case of transparent and
declared testing conditions.
A THERMODYNAMIC ANALYSIS OF PV PROCESS The PV productivity is affected by two main parameters:
solar effective irradiance and equilibrium temperature.
The equilibrium temperature is influenced by too many
factors, such as solar radiation collected, convective exchanges
with the surrounding air and radiant exchanges. Even
conductive heat transfer is difficult to evaluate and presents
certain variability depending on the fixing system and on
contacts with other modules. Also natural solar radiation
intensity is affected by different climatic and environmental
factors and is subject to a certain degree of uncertainness.
QIRR SUN
QIRR 1
QIRR 2
QCONV 1
v8
vdd QCONV 2
Fig. 1 - Diagram of the energy exchanges of a photovoltaic panel
It is well known that the equilibrium temperature can be
calculated as the result of the equation of equilibrium thermal
exchanges of the module. Many thermodynamic models of PV
modules have been presented in scientific literature. The most
interesting is certainly the Colozza formulation:
( )cond conv irr el cellQ Q Q Q Q f Tατ ≅ + + + = (1)
where τα is the coefficient of transmission-absorption panel. The terms which appear in the equation by Colozza are
graphically explicated in the image below (Fig. 1).
In testing conditions, but also in many Pv plants the
conductive term, Qcond, can be ignored, because both in the case
of a good insulation and of an isolated module it certainly
negligible. The term Qirr can be corrected to consider
atmospheric turbidity effects. The main problem of outdoor
tests is the convective problems which presents some problems
connected to his calculation. This term presents an evident
uncertainness related to the convective exchange term. It can
assume unpredictable variations depending on air temperature
and wind speed. This uncertainness condition reflects on the
problem of equilibrium temperature evaluation which affects
the performance of the modules directly, because they increase
as a function of equilibrium temperature.
In precedent papers it has evaluated the equilibrium
temperature in different cases, mostly concerning aeronautics
and high altitude performance prediction of PV plants [8-10],
but it has been evaluated for long term evaluations, which
reduce the error by assuming an average value of the above
influencing parameters.
It can be concluded that the evaluation of the equilibrium
temperature of PV modules, during natural sunlight outdoor
tests, appear present some problems because of results usually
depends on the location.
By this consideration all proposed outdoor testing
procedures can affected by errors which can grow in the case of
shirt time solar expositions.
So this kind of test, without a complete analysis of
environmental and climatic data can lead to unforced errors and
to a certain difficulty related to the possibility to have really
comparable results. But a complete declaration of the testing
conditions can help may be through software codes to produce
some kind of correlation between the performance of modules
which are not test simultaneously and/or in identical conditions.
INDOOR TESTING Indoor tests can certainly be considered more affordable
because, if a testing facility/apparatus is well designed in
standard climatic conditions and the exposure is realized by
well designed xenon lamps, it presents less degree of freedom
than outdoor testing. Notwithstanding this, also indoor tests,
presents problems and most evident is an exact solution of the
equilibrium equation (1).
Equilibrium temperature of the PV module is also difficult
to be measured because of it is related to cells temperature
while top and back temperature can be experimentally
measured and the temperature of the cells must be calculated on
a flat commercial module.
Both for performance and stress tests on photovoltaic
modules tests in a climatic chamber with controlled ventilation
can only guarantee identical testing condition can produce an
effective experimental characterization of PV modules end an
effective definition of characteristic curves such as the one
related to the effect of production variation as a function of
equilibrium temperature, or most precisely on the temperatures
of the top or the back face of the module, because they can be
easily measured and so are more significant than a temperature
such as the equilibrium temperature is indirectly calculated
because cannot be directly measured.
. Climatic Indoor testing equipments will also simplify the
realization of stress tests, especially regarding accelerated one.
These test, can permit a complete control of the testing process
parameters and will permit to conduce an effective analysis of
the influence of the different parameters on the failure modes
and on lifecycle duration. If variations of a single parameter are
performed it can be defined and weighted with more precision
the effect of any parameter on the failure mode and on
operative life of the module.
A COMMON MISTAKE One of the most common mistakes about PV testing
conditions has been clearly defined by David Burns during an
ASTM E44 discussion [32].
One of the most dangerous problems about PV testing is
“the erroneous concept that xenon-arc and natural outdoor
exposures will produce identical results… Yes, there are a few
6 Copyright © 2011 by ASME
general caveats noted in a subsequent section, however this
document is intended for industrial users 'of ordinary skill in
the art' rather than 'experts'. I fully support the use of xenon-
arc artificial for assessing the effects of irradiance on the
environmental stability of PV modules.”
This confusion and the misleading possibilities which
derive from this error can produce dangerous effects about
testing activities.
Some comparisons in terms of equivalence can be
approached by considering some well tested solar irradiation
calculation methods such as ASHRAE clear sky models. The
absence of any direct perturbation on radiation in xenon-arc
testing apparatus can produce large deviations from solar
natural irradiance effects.
To reduce this anomaly it can be also approached a further
standardization activity on solar emulation systems which can
define, in accord with scientific literature a detailed analysis on
artificial radiation spreading and diffusion to enhance the
possibilities of a more effective solar emulation even if in well
defined conditions.
EFFECTIVE COMPARATION POSSIBILITY The above description about the possibilities related to
indoor and outdoor testing, permit also to deduce that indoor
test in climatic chamber permit an effective comparison
between different modules and different producers.
The possibility of producing tests in well defined
conditions in a controlled environment and the possibility to
trace in a reduced time well defined experimental curves of
modules performances and their variation in function of the
most important environmental parameters. This testing
modality helps also to compare in identical conditions the
module lifecycle analyzing the influence of the most significant
climatic and environmental parameters on different failure
modes. This possibility will produce an effective possibility of
evaluation of the investments by customers and financial
institutions.
ASTM WK22010 The standard ASTM WK22010 New Guide for Testing
Performances, Weathering and Aging of Photovoltaic Modules
[12] aims to create the first organic framework for PV testing.
At the moment it is a growing Collaboration Standard Work
project which defines some important innovations about solar
photovoltaic equipments testing.
The main Scope of this standard under definition is moving
in the exact direction traced in this paper about problems
related to testing procedures for PV modules:
“In order to simplify standards for photovoltaic modules, a
general framework that defines objective parameters regarding
output production and lifecycle of modules is required, which
includes:
− quantifying the PV module performance decay from
the global effects of extended outdoor weather
exposure and induced fatigue stress;
− determine the mechanical resistance of modules to
weathering from exposure to real outdoor or
artificially created conditions, including extreme
weather events;
− determine the mechanical resistance and decay of
optical characteristics of glasses from exposure to real
outdoor or artificially created conditions, including
extreme weather events;
− determine the effective output production of modules
and the resulting decay, during the expected module
lifetime in real operating conditions and/or predefined
artificial weather conditions; in order to predict
performance in different real weather conditions from
test result parameters.
Any testing or stress procedure must satisfy three elemental
requisites: publication of test or stress conditions (e.g., use of
the same standards and methods and equivalent equipment),
reproducibility of the test or stress (e.g., at different locations,
and comparability of results (e.g., measure the same
parameters or implement the same stresses).
− Technical and geometric characteristics of reduced
size modules are defined to be as close in design and
function as possible to full-size modules.
− Stress and Test equipment and methodologies are fully
defined in order to ensure fully comparable results.
− Artificial weather conditions for stress are fully
defined to produce comparable results in terms of
aging, weathering, and decay during the modules
lifetime.
Accelerated exposure stressing is realized using simulated
sunlight in predefined conditions. Testing and stressing using
full-size modules are preferable, but in the case of accelerated
stressing reduced size compact devices are acceptable. If the
stress equipment is not large enough to accept full-size
photovoltaic modules, the stress and test procedures may only
be suitable for smaller test modules.
When using smaller test modules, the criteria for
equivalence with components in full-size modules shall be
specified. If the scaling can influence the results, the evaluation
of the influence of the factor scales must be clearly reported.
The stress and test methods do not provide for weathering
studies on individual components of photovoltaic modules, but
the methods can predict the influence of individual components
on module performance, resistance, and lifetime. No other
similar standards exist for long-term weathering of PV
modules. Users are primarily PV and test equipment
manufacturers.”
CONCLUSIONS Maybe that WK 22010 is not the best possible framework
to ensure a better quality of PV modules testing procedures, but
is actually the only attempt to define some basic and minimal
requirements to ensure that future testing on PV modules will
be more correct and valuable on the common basis of scientific
methodologies. More rigorous testing methodologies will
7 Copyright © 2011 by ASME
ensure producers, customers and financial institutions, because
they produce a more effective information to the market and
may help to define a correct commercial evaluation of products
based on effective technical parameters, stimulating positively
the competition.
The author of this Paper serves both in ASTM and ASME
and hopes that other can follow this method to increase the
cooperation possibilities between companies and academia.
In particular, the PV testing methods can be an interesting
field for a future active cooperation between academia,
laboratories, financial institutions and producer to define a new
generation of simple tests which can increase the volume of
information about solar photovoltaic modules and to validate
these expected results with more effective data collection
procedures scientifically validated.
NOMENCLATURE PV Photovoltaic
I Current Intensity [I],
E Tension [V],
P Power [W],
VOC open-circuit voltage [V],
VMP voltage at maximum power point, [V],
ISC short-circuit current [A],
Imp Current at maximum power point [A],
Pm Maximum Power [W],
MPP Maximum Power Point [V],
FF Fill Factor [%],
Q Heat Flux [W/m2],
REFERENCES [1] Liang Ji, PV Module Standards, Implementation, and
Update, Underwriters Laboratories Inc., SEMI
International Standards Workshop, October 9, 2009 Taipei
[2] Intertek, Five Reasons PV Modules Fail Product Certification Testing the First Time, corporate Whitepaper,
www.intertek-etlsemko.com
[3] IEC 61215 Ed.2: 2005-04 Crystalline silicon terrestrial photovoltaic (PV) modules – Design qualification and type
approval Ed.1: 1993-04
[4] IEC 61646 Ed.2: 2008-04 Thin-film terrestrial photovoltaic (PV) modules – Design qualification and type approval,
Ed.1: 1996-11
[5] IEC 61730-1 Ed.1: 2004-10 Photovoltaic (PV) module safety qualification - Part 1: Requirements for construction
[6] IEC 61730-2 Ed.1: 2004-10 Photovoltaic (PV) module safety qualification - Part 2: Requirements for testing
[7] ANSI/UL 1703-2004
[8] ASTM E44.09 Committee, ASTM E772-05 Standard Terminology Relating to Solar Energy Conversion
(WK26379 proposed revision);
[9] ASTM E44.09 Committee, ASTM E927-10 Standard Specification for Solar Simulation for Terrestrial
Photovoltaic Testing;
[10] ASTM E44.09 Committee, ASTM E948-09 Standard Test Method for Electrical Performance of Photovoltaic Cells
Using Reference Cells Under Simulated Sunlight
(WK22011 proposed revision);
[11] ASTM E44.09 Committee, ASTM E973-10 Standard Test Method for Determination of the Spectral Mismatch
Parameter Between a Photovoltaic Device and a
Photovoltaic Reference Cell
[12] ASTM E44.09 Committee, ASTM E1021-06 Standard Test Method for Spectral Responsivity Measurements of
Photovoltaic Devices;
[13] ASTM E44.09 Committee, ASTM E1036-08 Standard Test Methods for Electrical Performance of Nonconcentrator
Terrestrial Photovoltaic Modules and Arrays Using
Reference Cells;
[14] ASTM E44.09 Committee, ASTM E1038-10 Standard Test Method for Determining Resistance of Photovoltaic
Modules to Hail by Impact with Propelled Ice Balls
(WK26383 proposed revision);
[15] ASTM E44.09 Committee, ASTM E1040-10 Standard Specification for Physical Characteristics of
Nonconcentrator Terrestrial Photovoltaic Reference Cells
[16] ASTM E44.09 Committee, ASTM E1125-10 Standard Test Method for Calibration of Primary Non-Concentrator
Terrestrial Photovoltaic Reference Cells Using a Tabular
Spectrum;
[17] ASTM E44.09 Committee, ASTM E1143-05(2010) Standard Test Method for Determining the Linearity of a
Photovoltaic Device Parameter with Respect To a Test
Parameter;
[18] ASTM E44.09 Committee, ASTM E1171-09 Standard Test Methods for Photovoltaic Modules in Cyclic Temperature
and Humidity Environments (WK22006 proposed
revision);
[19] ASTM E44.09 Committee, ASTM E1328-05 Standard Terminology Relating to Photovoltaic Solar Energy
Conversion (WK26380 proposed revision);
[20] ASTM E44.09 Committee, ASTM E1362-10 Standard Test Method for Calibration of Non-Concentrator Photovoltaic
Secondary Reference Cells;
[21] ASTM E44.09 Committee, ASTM E1799-08 Standard Practice for Visual Inspections of Photovoltaic Modules;
[22] ASTM E44.09 Committee, ASTM E1802-07 Standard Test Methods for Wet Insulation Integrity Testing of
Photovoltaic Modules;
[23] ASTM E44.09 Committee, ASTM E1830-09 Standard Test Methods for Determining Mechanical Integrity of
Photovoltaic Modules (WK22007 proposed revision);
8 Copyright © 2011 by ASME
[24] ASTM E44.09 Committee, ASTM E2047-10 Standard Test Method for Wet Insulation Integrity Testing of Photovoltaic
Arrays;
[25] ASTM E44.09 Committee, ASTM E2236-10 Standard Test Methods for Measurement of Electrical Performance and
Spectral Response of Nonconcentrator Multijunction
Photovoltaic Cells and Modules;
[26] ASTM E44.09 Committee, ASTM E2527-09 Standard Test Method for Electrical Performance of Concentrator
Terrestrial Photovoltaic Modules and Systems Under
Natural Sunlight;
[27] ASTM E44.09 Committee, ASTM WK22009 New Test Method for Reporting Photovoltaic Non-Concentrator
System Performance;
[28] ASTM E44.09 Committee, ASTM WK22010 New Guide for Testing Performances, Weathering and Aging of
Photovoltaic Modules;
[29] ASTM E44.09 Committee, ASTM WK25362 New Practice for Accelerated Life Testing of Photovoltaic Modules.
[30] AA. VV., Standards Needs: Solar Energy, ASTM E44.09, Strategic Planning Session, , Thursday, February 19, 2009
[31] Trancossi M., Comment on.a Negative Vote on a Ballot, ASTM E44.09, 2010
[32] Burns D., Comment on.a Negative Vote on a Ballot, ASTM E44.09, 2009
[33] Colozza A., Initial Feasibility Assessment of a High Altitude Long Endurance Airship. NASA/CR 2003-
212724.
[34] Dumas A., Trancossi M. and Anzillotti S., “An Airship Design Methodology Based On Available Solar Energy In
Low Stratosphere”, International Mechanical Engineering
Congress And Exposition 2010, Imece2010-38931,
Vancouver Canada, 12-18 November 2010.
[35] Dumas A., Anzillotti S. and Trancossi M., Photovoltaic stratospheric isle for conversion in hydrogen as energy
vector, Proceedings of the Institution of Mechanical
Engineers, Part G: Journal of Aerospace Engineering,
P.E.P., ISSN 0954-4100
[36] Dumas A., Anzillotti S., Madonia M. and Trancossi M., ”Effects of Altitude on Photovoltaic Production of
Hydrogen”, ASME 5th International Conference on
Energy Sustainability”, ESFuelCell2011 2011-54624,
August 7-10, 2010, Washington, DC, USA (Under review)
[37] ASHRAE Technical Committee In: ASHRAE Handbook Fundamentals, American Society of Heating, Refrigerating
and Air Conditioning Engineers, New York (1972).
CONTACTS
Author :
Dr. Michele Trancossi Ph.D.:
ASTM E44 Committee:
9 Copyright © 2011 by ASME
