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2. SKEE 4653 - Chapter 2 - Photovoltaic Energy System

SKEE 4653
Photovoltaic and Wind
Energy Systems
Ir. Ts. Dr. Tan Chee Wei
Associate Professor
Electrical Power Engineering
School of Electrical Engineering
Chapter 2
Photovoltaic Energy
SKEE 4653 - Photovoltaic and Wind Energy Systems
Chapter 2. Photovoltaic Energy System
PV Generation Characteristics
PV Module and Array
Equivalent Electrical Circuit
Dependence of PV on Solar Irradiance and Temperature
PV Cells in Series and Parallel
PV Array Design
Maximum Power Point Tracking (MPPT)
Various MPPT Algorithms
PV System Components
Economical Analysis of Solar Energy
 The sun is the main source of all alternative energies on the
earth’s surface.
 Wind energy, bioenergy, ocean energy, and hydro energy are
derived from the sun.
 However, the term solar energy refers to the energy that is
harvested directly from the sun using solar cells, solar
concentrators, etc.
 Although solar energy is abundant on the earth ’ s surface,
harvesting it into a useful energy form is challenging and often
 Among all of the alternative energy resources, solar energy is
most costly for generation of electricity.
 Solar energy can be used either as a source of thermal energy
when using solar concentrators, or for direct electricity generation
when using photovoltaics (PV).
Introduction ...
 The amount of solar energy reaching a
specific location on the surface of the earth
at a specific time is called “insolation”, and
its value depends on several factors.
 Seasonal Variation
 Height of the Sun in the Sky
Introduction ...
 If the sun is directly overhead, and the sky is clear, the radiation on a
horizontal surface is about 1000 Wm-2.
 The solar radiation received on the surface is less when the sun is not
directly overhead:
- more atmospheric medium between the sun and the surface
- energy absorbed by the atmosphere
The generation of each sun-path line is done by
determining the exact position of the Sun as it
passes through the sky in sub-hourly increments
for each date - in most cases on the 1st or 21st of
each month. This is then projected from the sky
dome onto the flat image
Conceptualizing how the sun-path diagram actually
represents the entire sky dome.
Introduction ...
To Discover:
Introduction ...
 The sun releases about 46% of its energy as visible light. (only a
fraction of the total radiation spectrum)
 Only a fraction of the extraterrestrial irradiance reaches the earth’s
surface directly, whilst other parts are scattered by other atmospheric
particles into other directions.
 The air mass number (AM) refers to the relative path length of the
direct solar beam through the atmosphere.
- the sun is perpendicular to the surface of the earth, this
condition is known as AM 1 for terrestrial
- and AM 0 for extraterrestrial.
Introduction ...
The Sun's Energy
Movie Clip:
Potovoltaic effect
Photovoltaic Generation Characteristics
The Photovoltaic (PV) Effect
It is the fundamental physical process of a PV cell, in which it
converts the solar irradiance into electrical energy.
 Solar irradiance is composed of photons which are packets of solar
These photons contain different amounts of energy that correspond
to different wavelengths of the solar spectrum.
During daylight, when photons strike onto the surface of a PV
module, some of the photons are reflected by the surface while the
remaining photons may be absorbed by the PV cells or pass through
the PV module.
Then, the energy of the absorbed photons is transferred to an
electron in an atom of the semiconductor device in the PV module.
Photovoltaic Generation Characteristics ...
Thus, an electron-hole pair is created and both electron and hole
begin to move through the semiconductor (but in the opposite
The commonly used semiconductor materials are monocrystalline silicon, poly-crystalline silicon and amorphous silicon.
The electric field at the p-n junction of the semiconductor sorts
out the photo-generated electrons and holes, driving new electrons
to one side of the barrier and new holes to another side.
This sorting process creates a driving force to the charge carries
in an electrical circuit.
Therefore, if the PV module is attached to an external circuit or to
a DC load, electrons can flow from the n-type semiconductor
through the circuit and flow back to the p-type semiconductor,
where the electrons combine with the holes to repeat the process.
The Photovoltaic Effect
Construction of solar cell and photovoltaic effect
The level of energy absorbed by different materials of PV cells
Test 1
Week 7: Tuesday 8.30 am
30th November 2021 (Tuesday)
1. PV is made of ___________
2. What is PV effect?
3. _______ is the atom from sunlight that converts
__________ to ___________ by PV cell.
4. The energy of atom in the sunlight is measured in
terms of unit __________
5. To avoid reflection of sunlight on PV module, it has
____________ on top of the module.
PV Cell, Module and Array
PV Cell, Module and Array
PV Panel Efficiency
Total PV Panel efficiency is measured under standard test conditions (STC),
based on a cell temperature of 25°C, solar irradiance of 1000W/m2 and Air Mass
of 1.5. The efficiency (%) of a panel is calculated by the maximum power rating
(W) at STC, divided by the total panel area in meters.
Top 10 Most Efficient Solar Panels *
2021 has seen a surge in manufacturers releasing more efficient solar panels
based on high purity N-type and heterojunction HJT cells. For the first time, the
efficiency of the top 10 panels is now above 21%.
Monocrystalline Solar Panels
“Mono” means “single”; made of single pure silicon crystal.
in rounded shape and the Silicon crystal bars look like cylindrical
Efficiency are 15-20%, the latest achieves 25% in the labs and 21% is verified; the XSeries of SunPower PV (Photovoltaic panels) provides 21.5% efficiency.
requires the least amount of space and takes up a small area on the roof; average life
of about 25 years (25 to 30 year life expectancy-claimed by manufacturers).
Its performance is better than polycrystalline at same rating light conditions.
the most efficient available PV module, most popular technology in the market
Monocrystalline solar panels are costly; initial cost is too high.
A large amount of pure silicon ends up as waste. To make silicon wafers and arrays in
large cylindrical shape (make monocrystalline Silicon is called Czochralski process), the
four ends of the PV cells are cut out of the ingots  large amount of pure Silicon waste.
more efficient when the temperature goes up (warm weather and full sunshine)
Polycrystalline Solar Panels
“Poly” means “many or multi”; made of a number of different pure
silicon crystals; rectangular shape, need less silicon as compared to
monocrystalline, less expensive, but their efficiency is also lower than the
monocrystalline PV cells. It is also called polysilicon or multi-crystalline silicon and first
introduces in 1981 in the market.
• lower heat tolerance (which means their performance is lower in high temperature as
compared to monocrystalline solar PV modules)
• the process to produce the polycrystalline silicon is cost less and less complicated.
• the efficiency is slightly lower than monocrystalline  approximately 13.5 - 17%.
• the same surface of polycrystalline PV modules (in size) would produce less power as
compare to monocrystalline solar panel (but this is not always the case).
• It is not suitable to use as compared to thin film and monocrystalline solar panel in
terms of blue color. elegance (when needed) because it hasn’t a uniform appearance,
but only random and odd
Thin Film Solar Cells (TFSC) or (TFPV)
TFSC is also known as Thin Film Photovoltaic Cells (TFPV)
or Amorphous PV Modules; Integrating one or more thin layers of PV
materials or thin film (TF) on a substrate, e.g. metal, glass, plastic etc.
Types of Thin Film Solar panels - by which PV materials are integrated on a substrate:
 Amorphous Silicon (a-Si/TF-Si)
 Copper Indium Gallium Selenide (CIGS/ CIS)
 Cadmium Telluride (CdTe)
Thin film solar panels are cheaper but less efficient than conventional c-SI technology.
However, recent technology development verifies the lab cell efficiency of CdTe and CIGS/ CIS
reached up to 20%.
 Large scale production - less complicated than crystalline based PV cells; lower cost as
compared to other monocrystalline PV / Solar panels.
 uniform appearance - more attractive (beautification purpose); in flexible form
 It has high temperature tolerance - high temperature and shading have less impact
 It requires a lot of space; additional support structure, cables, maintenance, etc. for thin film
solar panel installation makes the system costly.
 life expectancy of thin film is lower than that of poly- and monocrystalline solar panels.
Half-cut PV Cells
• Half-cut solar cells are essentially the same silicon solar cells – except that they’ve
been cut in half with a laser cutter. This means that instead of the usual 60 cells
found in a conventional solar panel, one with half-cut cells would have 120.
Benefits of half-cut cells
 improve solar panel performance by increasing efficiency, thereby boosting energy
 Reduction of resistive loss
 Improved low light performance
 Durability
Half-cut PV Cells
Benefits of half-cut cells
 Reduction of resistive loss
• In the process of converting sunlight into electricity, the electrical current transport in
traditional solar cells leads to a certain degree of power loss. Current in solar cells is
transported via thin metal ribbons crossing their surface and connecting them to neighbouring
wires and cells. By halving each solar cell, current generation per cell is also halved. The
reduced amount of current flowing within the solar panel also reduces resistive losses.
 Improved low light performance
• Half-cut cell photovoltaic solar panels are not affected by shade or low-light conditions as much
as conventional solar panels. This is primarily a result of a subtle difference in the wiring system
of solar panels with half-cut cells.
• Full cells in typical solar panels are held together in a system called series wiring, with the cells
arranged in rows. If a row of cells is hidden from sunlight, the entire row is affected and won’t
produce energy. Since standard panels comprise three different rows of cells, anytime one row
is shaded, one-third of the panel would be unproductive.
• Just like regular solar cells, half-cut cells are held together through series wiring. But since halfcut cell photovoltaic solar panels have twice the number of cells, there’s also twice the number
of cell rows.
• So, if a single row of half-cut cells is stuck in the shade, the solar panel would lose less power,
since only a sixth of the combined panel energy output is affected.
Half-cut PV Cells
Half-cut PV Cells
• microinverters provide a significant advantage in shaded conditions over
competing string and central inverter systems.
• Microinverters optimize the power production from each individual module to
deliver maximum energy from the array; If you get shade on a module, it only
affects that one particular module.
• In contrast, with string and/or central inverters, shading on a single module
affects all the modules in that array.
• Microinverters minimise losses caused by panel mismatch, degradation, cabling,
and external factors like soiling. In full sun or shade, you harvest more energy
with Microinverters.
Solar Grid Tied Inverters
Solar Grid Tied Inverters
What is PERC solar cell technology?
• “Passivated Emitter and Rear Contact” solar cells, known as PERC solar
cells, are becoming more common today as an option for making solar
• PERC solar cells are modified conventional cells that enable the cells to
produce 6 to 12 percent more energy than conventional solar panels.
• PERC solar cells have an extra layer within the back side of the cell. This
allows some of the sun’s rays to reflect back into the solar cell, giving them
another opportunity to be turned into energy.
What is PERC solar cell technology?
Batteries for Solar PV System
There are two main kinds of deep cycle batteries:
 lead-acid and
 Lithium
 Lead-acid batteries have a lower upfront cost, while lithium batteries have
the longest lifespan.
 Flooded lead-acid batteries require maintenance, and more expensive
sealed lead acid batteries are maintenance-free.
Batteries for Solar PV System
 Batteries are the primary storage source for off-grid systems, but they
also work as an emergency backup power source for grid-tied systems.
 Installing a grid-tied system with a solar battery backup also gives you the
option to sell excess stored power back to the utility company at a later time.
Deep Cycle Batteries
 Unlike a traditional car battery, deep-cycle batteries provide a long, steady
stream of power.
 It can provide a short burst of power, but nothing like a car battery.
 Deep cycle batteries are also lead-acid batteries but they are designed to be
discharged and recharged regularly.
 They have strong plates inside of them that allow their power to be
completely drained repeatedly without causing damage to the battery itself.
 If you were to completely drain a car's battery over and over again, you would
dramatically shorten its life.
 Deep cycle batteries were not made to power most vehicles.
 However, they are often used for recreational vehicles, boats, and golf carts.
Because they deliver a steady flow of power over a long period of time, these
batteries are also useful in solar panels and other plug-in electronics.
Batteries for Solar PV System
Flooded lead-acid battery, the AGM battery, and GEL battery
 In flooded batteries, the electrolyte is in liquid form and can flow.
 Whereas in AGM and GEL battery, the electrolyte cannot flow. And
therefore, these batteries can be used in any orientation.
 Both the AGM and GEL batteries are maintenance-free where in flooded
batteries, the water for the electrolyte has to be topped up from time to
Batteries for Solar PV System
A Deep Cycle Battery is the battery that user can charge and discharge
again and again without posing much damage to the cells of the battery. It is
a kind of lead-acid battery, intended to discharge between 45% and 75% of
its inbuilt capacity.
Batteries for Solar PV System
AGM battery
Specifications (per 2 V battery):
•Nominal voltage: 2 V
•Nominal capacity: 500 Ah (10 h rate) / 508 Ah (20 h rate)
•Maximum charging current: 100 A
•Cycle lifetime at 30% D.O.D.: 1200
•Pressure control: safety valve installed
•Terminal type: M10 bolts
•Operating temperature: from -10 degree C to +40 degree C
•Size: 242 x 174 x 365 mm
•Weight: 27 kg
Specifications (entire 48 V battery bank):
•Nominal voltage: 48 V
•Nominal capacity: 24 kWh
•Maximum charging current: 100 A
•Charging voltage: cycle use 56.4 V, standby use 54.8 V
•Temperature compensation: cycle use -120 mV/degree C,
standby use -72mV/degree C
•Size: 1290 x 1140 x 670 mm (when positioned in racking)
•Weight: 720 kg (including racking)
Suitable applications:
The long service life and improved depth of discharge of this battery bank make it ideal for applications requiring constant, reliable
and powerful energy supply. Such applications include, but are not limited to:
- Solar, wind and hybrid energy systems
- Household off-grid and grid tie power systems
- Emergency or back-up UPS systems
- Energy storage for telecommunications or networking equipment
- Power stations
Batteries for Solar PV System
Additional Note:
 Nickel–iron batteries are
resilient to overcharging
and discharging along
with high temperature
and vibrations resistance.
 However, there are some
disadvantages in these
batteries such as:
 at low
temperatures the
performance is
 low energy
density of 50 Wh/kg
 these battery
discharge high
rates of about 40%
every month.
 In
batteries are not cheaper
and if compared to lead
acid and Li-ion batteries
these are almost four
times more expensive.
Equivalent Electrical Circuit
I  I L  I D  I sh
 I  I L  I o e
V  I RS
 V I R
 1 
I L  I LT1 1  Ko  T T1 
I L T 1
Ko 
 G 
 I SC T 1 
 ( nom ) 
I SC (T 2)  I SC (T 1)
T2  T1
T 
I o  I o T 1    e
 T1 
qVg  1 1 
  
nk  T T1 
q VOC ( T 1)
I o T 1  I SC T 1  e
Cell output current (A)
Photocurrent (A)
Diode current (A)
Shunt current (A)
Cell reverse-saturation current (A)
Short circuit current (A)
Cell terminal voltage (V)
Open circuit voltage (V)
Cell thermal voltage, VT = kT/q (V)
Short circuit current-temperature coefficient at 25°C
Solar irradiance (Wm-2)
Solar irradiance at nominal temperature, 25°C (1000 Wm-2
Ideality factor (diode quality factor)
Boltzmann’s constant
Electronic charge
Temperature of the photovoltaic device (K)
Nominal temperature (273 + 25) K
Temperature at (273 + 75) K
Lumped series resistance
Lumped shunt resistance
Equivalent Electrical Circuit
Typical I-V and P-V characteristic of a PV module.
Equivalent Electrical Circuit
Typical I-V and P-V characteristic of a PV module.
• VOC = open-circuit voltage
This is the maximum voltage that the array provides when the terminals are not
connected to any load (an open circuit condition). This value is much higher than Vmp
which relates to the operation of the PV array which is fixed by the load. This value
depends upon the number of PV panels connected together in series.
• ISC = short-circuit current
The maximum current provided by the PV array when the output connectors are shorted
together (a short circuit condition). This value is much higher than Imp which relates to the
normal operating circuit current.
• MPP = maximum power point
This relates to the point where the power supplied by the array that is connected to the
load (batteries, inverters) is at its maximum value, where MPP = Imp x Vmp. The
maximum power point of a photovoltaic array is measured in Watts (W) or peak Watts
• FF = fill factor
The fill factor is the relationship between the maximum power that the array can
actually provide under normal operating conditions and the product of the open-circuit
voltage times the short-circuit current, ( Voc x Isc ) This fill factor value gives an idea of
the quality of the array and the closer the fill factor is to 1 (unity), the more power the
array can provide. Typical values are between 0.7 and 0.8.
• %eff = percent efficiency
The efficiency of a photovoltaic array is the ratio between the maximum electrical
power that the array can produce compared to the amount of solar irradiance hitting
the array. The efficiency of a typical solar array is normally low at around 10-12%,
depending on the type of cells (monocrystalline, polycrystalline, amorphous or thin
film) being used.
Dependence of PV on
Solar Irradiance and Temperature
Quiz again….
1.Sketch the I-V and P-V characteristics based on the information given above.
2.What happen to the above curves if the irradiance fall half of the rated
3.Sketch the same characteristics curves for 3 modules connected in series.
4.If 2 series connected modules are connected in parallel, sketch again…
You need to label all important parameters – both the name and its values...
5. What is the power generation at NOCT?
• New concept of PV cells
– Full cell vs. half cell
• New concept of PV systems
– Floating solar
– PV agricultural
PV Cells in Series and Parallel
PV Cells in Series and Parallel ...
PV Cells in Series and Parallel ...
Determine the total PV output voltage and current.
PV Array Design
PV Array Design ...
PV Array Design ...
PV Cell and Module Ratings
Standard Test Conditions (STC)
In order to compare solar cells on a like for like basis a set of
Standard Test Conditions (STC) has been defined.
The conditions are:
Normal Irradiance of 1000 W/m2, Cell Temperature 25 °C (77
°F) and Air Mass =1.5
Normal Operating Cell Temperature (NOCT)
Normal Irradiance 800 W/m2, Air Temperature 20°C (68°F),
Wind Velocity (cooling) of 1 meter per second (2.24 miles per
hour), with the rear side of the solar panel open to the air flow.
What will be the average electrical power output
from the above "250 W" solar panel?
Assuming a fixed solar array located in the North East of the USA, facing South and tilted towards the Sun at an
angle corresponding to the latitude of the site, the NREL map shows that the insolation is around 4 kWh/m2/day.
In the sunnier South West the insolation will be about 50% more at 6 kWh/m2/day which translates directly into
50% more electrical output power from the same solar panels.
The 60 cell solar panel has an effective area of 60 X 0.156 m2 = 1.46 m2
In the North East this panel will therefore intercept 1.46 X 4 = 5.84 kWh of solar energy per day.
This insolation is equivalent to a constant (average) solar power of
5.84 kWh / 24 hr = 243.3 W
during the 24 hour day.
The conversion efficiency of the solar cells is calculated from the manufacturer's specified electrical power output
achieved from the NOCT specified power input.
The energy intercepted by the 1.46 m2 panel under NOCT conditions will be 1.46 X 800 = 1168 W
The specified electrical output power from the panel is 183.3 W
Thus the conversion efficiency = 183.3 / 1168 X 100 = 15.7%
Applying this conversion efficiency to the actual insolation of 243.3 W gives an average electrical power output
from the panel of
243.3 X 0.157 = 38.2 W (This corresponds to an electrical output of 26.2 W/m2)
Not bad for a solar panel rated at 250 Watts?!
PV Module Data Sheet – by the manufacturer
PV Axis Tracking
PV Axis Tracking
Solar tracking is vital to the efficiency of a system
 The main difference between solar trackers and fixed-tilt PV systems is that the modules
of solar trackers can change their tilt angles at different times of the day.
 The time during which modules are directly facing the sun is maximized, and this in turn
raises the power generation of the system.
 BIG SUN, the premier specialist in solar energy solutions, says solar trackers has up to
60% more annual power output than that of fixed-tilt PV systems. This finding is based on
data from actual PV projects undertaken by the company.
 Solar trackers are divided into two main types: single-axis trackers (SAT) and dual-axis
 Simply said a pyranometer is a device that measures solar irradiance from a
hemispherical field of view incident on a flat surface.
 The SI units of irradiance are watts per square meter (W/m²).
 Pyranometers measure global irradiance:
 the amount of solar energy per unit area per unit time incident on a
surface of specific orientation emanating from a hemispherical field of view
Maximum Power Point Tracking (MPPT)
An MPPT algorithm sets a reference value for one of the variables
(duty-cycle, current or voltage) in the power converter that interfaces
the PV array to a load.
Off-line MPPT algorithms:
- require prior information about the PV array and some measurements
On-line MPPT algorithms:
Hill Climbing
Perturb and Observe (P&O)
Incremental Conductance
Hybrid MPPT control
Maximum Power Point Tracking (MPPT) ...
The typical three types of Maximum Power Point Tracking (MPPT)
control methods:
1.Direct duty-cycle control
2.Current-mode control
3.Voltage-mode control
Example: The control block diagram of the P&O MPPT
algorithm for a current-mode control converter.
1000 W/m2
900 W/m2
800 W/m2
700 W/m2
Simulation Result
500 W/m2
400 W/m2
- PV Power/Energy
300 W/m2
- PV Characteristics
1000 W/m2
300 W/m2
1000 W/m2
300 W/m2
Maximum Power Point Tracking (MPPT) ...
 The diagram below shows the performance of a 17 V, 4.4 A, 75 W PV
array used to top up a 12 V battery.
If the actual battery voltage is 12 V, the resulting current will be about
4.5.A and the power delivered by the array will be just over 50 W rather
than the specified 75 W: an efficiency loss of over 30%.
 Maximum Power Point Tracking is designed to overcome this problem.
Various MPPT Algorithms
PV System Components
Solar modules
Combiner box - DC Breakers and combines all the wiring down to two wires Positive and Negative
Charge Controller - controls the current so that the battery bank does not get over charged
DC Disconnect - circuit isolation with DC and AC Breakers
Battery bank - 12 volts or 24 Volts, or 48 Volts
Inverter/Charger - DC to AC conversion
Battery monitor
pole mount or
roof mount.
Building Integrated Photovoltaic (BIPV)
 Building Integrated PV are
photovoltaic materials that are used
to replace conventional building
materials in parts of the building
envelope such as
• roof,
• tiles,
• skylights and
• facades.
Building Integrated Photovoltaic (BIPV)
Design of BIPV Systems
• BIPV systems should be approached to where energy conscious design
techniques have been employed, and equipment and systems have been
carefully selected and specified.
• They should be viewed in terms of life-cycle cost, and not just initial, first-cost
because the overall cost may be reduced by the avoided costs of the building
materials and labor they replace.
• Design considerations for BIPV systems must include the building's use and
electrical loads, its location and orientation, the appropriate building and safety
codes, and the relevant utility issues and costs.
Building Integrated Photovoltaic (BIPV)
Steps in designing a BIPV system include:
work environment.
Carefully consider the application of energy-conscious design practices
and/or energy-efficiency measures to reduce the energy requirements of
the building.
This will enhance comfort and save money while also enabling a given BIPV
system to provide a greater percentage contribution to the load.
Choose Between a Utility-Interactive PV System and a Stand-alone
PV System:
• The vast majority of BIPV systems will be tied to a utility grid, using the grid as storage and
backup. The systems should be sized to meet the goals of the owner—typically defined by budget or
space constraints; and, the inverter must be chosen with an understanding of the requirements of the
• For those 'stand-alone' systems powered by PV alone, the system, including storage, must be
sized to meet the peak demand/lowest power production projections of the building. To avoid over
sizing the PV/battery system for unusual or occasional peak loads, a backup generator is often used.
This kind of system is sometimes referred to as a "PV-genset hybrid."
Building Integrated Photovoltaic (BIPV) ...
Shift the Peak:
If the peak building loads do not match the peak power output of the PV array, it may be economically
appropriate to incorporate batteries into certain grid-tied systems to offset the most expensive power
demand periods. This system could also act as an uninterruptible power system (UPS).
Provide Adequate Ventilation:
PV conversion efficiencies are reduced by elevated operating temperatures. This is truer with
crystalline silicon PV cells than amorphous silicon thin-films. To improve conversion efficiency, allow
appropriate ventilation behind the modules to dissipate heat.
Evaluate Using Hybrid PV-Solar Thermal Systems:
As an option to optimize system efficiency, a designer may choose to capture and utilize the solar
thermal resource developed through the heating of the modules. This can be attractive in cold climates
for the pre-heating of incoming ventilation make-up air.
Consider Integrating Daylighting and Photovoltaic Collection:
Using semi-transparent thin-film modules, or crystalline modules with custom-spaced cells between
two layers of glass, designers may use PV to create unique daylighting features in façade, roofing, or
skylight PV systems. The BIPV elements can also help to reduce unwanted cooling load and glare
associated with large expanses of architectural glazing.
Building Integrated Photovoltaic (BIPV) ...
Incorporate PV Modules into Shading Devices:
PV arrays conceived as "eyebrows" or awnings over view glass areas of a building can provide appropriate
passive solar shading. When sunshades are considered as part of an integrated design approach, chiller
capacity can often be smaller and perimeter cooling distribution reduced or even eliminated.
•Design for the Local Climate and Environment:
Designers should understand the impacts of the climate and environment on the array output. Cold, clear
days will increase power production, while hot, overcast days will reduce array output;
Surfaces reflecting light onto the array (e.g., snow) will increase the array output;
Arrays must be designed for potential snow- and wind-loading conditions;
Properly angled arrays will shed snow loads relatively quickly; and,
Arrays in dry, dusty environments or environments with heavy industrial or traffic (auto, airline)
pollution will require washing to limit efficiency losses.
•Address Site Planning and Orientation Issues:
Early in the design phase, ensure that your solar array will receive maximum exposure to the sun and will
not be shaded by site obstructions such as nearby buildings or trees. It is particularly important that the
system be completely unshaded during the peak solar collection period consisting of three hours on either
side of solar noon. The impact of shading on a PV array has a much greater influence on the electrical
harvest than the footprint of the shadow.
Building Integrated Photovoltaic (BIPV) ...
Consider Array Orientation:
Different array orientation can have a significant impact on the annual energy output of a system, with
tilted arrays generating 50%-70% more electricity than a vertical façade.
Reduce Building Envelope and Other On-site Loads:
Minimize the loads experienced by the BIPV system. Employ daylighting, energy-efficient motors, and
other peak reduction strategies whenever possible.
The use of BIPV is relatively new. Ensure that the design, installation, and maintenance professionals
involved with the project are properly trained, licensed, certified, and experienced in PV systems work.
In addition, BIPV systems can be designed to blend with traditional building materials and designs, or
they may be used to create a high-technology, future-oriented appearance. Semi-transparent arrays of
spaced crystalline cells can provide diffuse, interior natural lighting. High profile systems can also
signal a desire on the part of the owner to provide an environmentally conscious
DIY Solar Panel System:
Components, Cost & Savings
Considering only the rated voltage
above, what type of power electronic
converter can be used to achieve 400
if only
a. 8 modules are available
b. all 12 modules should be used
For each case above, calculate the
duty-cycle. Then, determine the
fundamental voltage if the M is 0.8 in
an PWM inverter.
** what are the assumptionsmade in
solving the above questions?
In a stand-alone PV system with battery storage, estimate the capacity of the
battery required to store all the energy harvested during the daytime in order to
be discharged at nighttime.
- 10 PV modules from data sheet above
- not considering the temperature effect, but only the rated parameters
- average of 8 hours daily sunshine with an average of 50% from the rated power.
Economic Analysis of Solar Energy
 The economic calculation can be performed using the life-cycle
cost (LCC) where consideration of costs over the entire lifetime of the
PV system is made, which is expressed as
where capital costs include the cost of PV array, battery and balance
of system, O&M Cost is the operational and management cost.
 The asterisk (*) indicates that the parameter is based on present
worth value, in which the annual value of a parameter is multiplied
with the present worth factor (Pa)
Economic Analysis of Solar Energy ...
The present worth factor (Pa) defined as follows
where i is the excess inflation rate, d is the discount rate at which
the value of money would increase if invested and m is the number
of years for a recurring parameter.
Economic Analysis of Solar Energy ...
 Another measure in an economic evaluation is the payback period for
a PV system.
I t is the time it takes for the total cost to be ‘paid for’ by the
monetary profits and other benefits of the system. In this study, the
payback period, n (years) is calculated using the following equations.
where ‘Savings’ refer to the saving made in the annual electricity, which are
contributed by the avoided electricity cost where the partial demand are
supplied by PV energy and battery energy during demand shifting operation.
Economic Analysis of Solar Energy ...
To Discover:
PV Payback calculator
Economic Analysis of Solar Energy ...
The levelized cost of electricity (LCOE) is a measure of a power source
which attempts to compare different methods of electricity generation on a
comparable basis.
It is an economic assessment of the average total cost to build and operate a
power-generating asset over its lifetime divided by the total power output of
the asset over that lifetime.
The LCOE can also be regarded as the cost at which electricity must be
generated in order to break-even over the lifetime of the project.
To Discover:
Levelized Cost of Energy Calculator
PV Systems and Applications
PV Systems and Applications
PV Systems and
PV Systems and Applications …
 Stand-alone PV systems and grid-connected PV systems.
Grid-Connected PV systems
 Estimation of the rated power and area required for the PV array.
 Exploring the interactions between PV modules and inverters, and
how those impact the layout of the PV array.
 Considering details about voltage and current ratings for fuses,
switches and conductors.
Stand-Alone PV systems
 Load Analysis
 PV Sizing
 Battery Sizing
 Generator Sizing
 System Costs
PV Agriculture
Photovoltaic agriculture, the combination of photovoltaic power generation and
agricultural activities, is a natural response to supply the green and sustainable
electricity for agriculture.
Foreign Investment and Job Creation
Estimating 50,000 jobs created by RE plants. If we are to spread this over the course of
9 years, that would be about 5,000 to 6,000 jobs created every year; a very interesting
prospect for an emerging economy. – New Straits Times
The roof of Suria KLCC no longer sits idle. The 685 kWp photovoltaic system installed there can supply
30% of the mall’s energy needs or power 250 typical Malaysian households for a month. It saves
emission of 360 tonnes of carbon dioxide annually. — Suria KLCC
A closed landfill in Pajam, Negri Sembilan, gets a new lease of life – as a 8 MW solar farm by Cypark
The 5 MW Fortune 11 solar farm in Sepang, Selangor, sits on oil palm land leased from Malaysia
Airports Holdings Bhd. The panels move with the sun so as to tap maximum solar radiation.
Daily Solar Energy Curve, How Solar Power Systems Work
throughout the Day?
End of Chapter 2
Thank you