POWER PLANT ENGINEERING
Experiment No. – 4
Title-solar power system
Aim-To perform analysis of solar power system.
Theory-
Solar cell efficiency refers to the portion of energy in the form of sunlight that can be converted
via photovoltaic into electricity. The efficiency of the solar cells used in a photovoltaic system,
in combination with latitude and climate, determines the annual energy output of the system.
For example, a solar panel with 20% efficiency and an area of 1 m2 will produce 200 W at
Standard Test Conditions, but it can produce more when the sun is high in the sky and will
produce less in cloudy conditions or when the sun is low in the sky. In central Colorado, which
receives annual insolation of 5.5 kWh/m2/day (230W/m2) such a panel can be expected to
produce 400kWhof energy per year. However, in Michigan, which receives only 3.8
kWh/m2/day, annual energy yield will drop to 280 kWh for the same panel. At more northerly
European latitudes, yields are significantly lower: 175 kWh annual energy yield in southern
England.
Several factors affect a cell's conversion efficiency value, including its reflectance efficiency,
thermodynamic efficiency, charge carrier separation efficiency, charge carrier collection
efficiency and conduction efficiency values. Because these parameters can be difficult to
measure directly, other parameters are measured instead, including quantum
efficiency,opencircuit voltage(VOC) ratio, and Fill factor(described below). Reflectance losses
are accounted for by the quantum efficiency value, as they affect "external quantum efficiency."
Recombination losses are accounted for by the quantum efficiency, VOC ratio, and fill factor
values. Resistive losses are predominantly accounted for by the fill factor value, but also
contribute to the quantum efficiency and VOC ratio values.
As of December 2014, the world record for solar cell efficiency at 46.0% was achieved by using
multi-junction concentrator solar cells, developed from collaboration efforts of
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POWER PLANT ENGINEERING
Soitec ,CEA-Leti, France together with Fraunhofer ISE, Germany. This is above the standard
rating of 37.0% for a polycrystalline photovoltaic or thin-film solar cells.
The purpose of these solar panels is to meet the growing demand for renewable energy
resources, while expanding the available Electrical Engineering curriculum. The current
coursework provided in this area relates to the conceptual understanding of how photovoltaic
panels operate and their current role in society. To reinforce these concepts and show what the
complete power system would include, this test procedure is based on the fundamental
principles of this system in relation to power distribution.
Understanding the Parts
Read this section carefully to understand what electrical parts and devices are used in this
laboratory activity.
Component Figure
Digital Multimeter (DMM):
These devices allow us to measure DC/AC currents and voltages,
among other electrical characteristics. When a DMM is used in
a circuit to measure voltage it is called a Voltmeter. The dashed
square shows which pins of the DDM are used when it is used as
a voltmeter. When a DMM is used in a circuit to measure current
it is called an Ammeter. The blue arrows in the figure indicate
which pins of the DDM are used
he
it is used as an Ammeter.
Charge Controller:
A charge controller, or charge regulator is basically a voltage
and/or current regulator to keep batteries from overcharging. It
regulates the voltage and current coming from the solar panels
going to the battery. Most "12 volt" solar panels put out about 16
to 20 volts, so if there is no regulation the batteries, which are
connected to them to be charged will be damaged from
overcharging. Most batteries need around 14 to 14.5 volts to get
fully charged.
Light Bulb:
When the bulb is hooked up to a power supply, an electric current
flows from one contact to the other, through the wires and the
filament (filament sits in the middle of the bulb). Electric current
in a solid conductor is the mass movement of free electrons a
negatively charged area to a positively charged area. As the
electrons zip along through the filament, they are constantly
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bumping into the atoms that make up the filament. The energy
of each impact vibrates an atom -- in
other words, the current heats the atoms up. As a result, as
filaments are heated to a high enough level -- around 4,000
degrees Fahrenheit (2,200 degrees C) in the case of a light bulb
-- they will emit a good deal of visible light. There are many
different types of lamps, characterized by how they are built and
much power (in Watts) they consume.
Alligator Clips:
These clips are used to make connections between
the devices when they don’t reach one another. It
is important to ensure adjacent wires do not touch
each other, as this can damage the device or burn
your hand.
Kill-A-Watt:
Using these devices you can monitor how much electricity an
electrical appliance is consuming. Kill-A-Watt also monitors the
voltage, current, and frequency of the AC signal turning on the
appliance.
Power Inverter:
These devices convert the variabledirect current(DC) output of a
photovoltaic(PV)solar panel(or just a battery) into autility
frequencyalternating current(AC) that can ultimately be fed to
turn on an electrical appliance. In front of the Inverter you can
see a USB interface, providing a 5-Volt output.
Light Meter:
A light meter is a device used to measure the amount oflight.
Inphotography, a light meter is often used to determine the
properexposurefor a photograph. In this laboratory exercise we
use light meters to show how the generated electricity from a
solar panel is related to the intensity of the sunlight.
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Battery:
While there are many different types of batteries, the basic
concept by which they function remains the same. When a
device is connected to a battery, a reaction occurs that produces
electrical energy. This is known as an electrochemical reaction.
For this experiment we use a 12 V battery.
Solar Panel/Module:
The solar cells, also called photovoltaic (PV) cells, as the name
implies (photo meaning "light" and voltaic meaning
"electricity"), convert sunlight directly into electricity. A solar
module is a group of cells connected electrically and packaged
into a frame (more commonly known as a solar panel), which can
then be grouped into larger solar arrays.
Requirements
The goal of this procedure is to develop a thorough analysis of the solar panel system to fully
understand the circuit properties associated with this design. In order to create this complete
analysis, each element of the circuit must be tested to determine its functionality and
specifications. The best measurement to regulate the efficiency of each stage was the voltage
at the output terminals. When a load is then placed across the output terminals, the power can
be measured to find overall efficiency when more stages are added to the network. First, the
output of the solar panel will need to be measured to understand the stages taken to produce
the output voltage of 12V needed to charge the battery. Using the open circuit voltage of the
solar panel and the output of the charge controller, the exact functionality of the charge
controller can be determined. If the charge controller functions as a DC-to-DC converter
stepping the voltage down to the needed 12V, what output will be given if there is less than
ideal sunlight. If this is not the correct operation, then how does the charge controller regulate
the output voltage? Also, the lighting configuration present on the charge controller is
important to consider to ensure that the ‘charging light is lit when the battery is charging and
the ‘charged light is lit when the battery is finally fully charged. Once the operation of the
battery charge controller is confirmed, the battery can be connected to determine the complete
DC network characteristics. The testing requirements needed for the battery will be based on
the charging time in relation to the final voltage found across the battery terminals and the
output current.
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When the battery becomes fully charged, the AC Inverter can be tested to determine its
complete operation. The required input voltage and measured output voltage can be used to
determine the efficiency of the inverter and the overall efficiency of the entire system. The AC
Inverter may have very specific requirements when loaded in regards to the available voltage
and current. An important state to consider is when the solar panel is not given enough sunlight
to power the AC Inverter and a given load.
Observation-
Solar Panel specification
1. Maximum Power = 295 W
2. Optimum operating voltage= 32.3 V
3. Optimum operating Current = 9 A
4. Open circuit voltage = 39.5 V
5. Short circuit current = 9.75 A
= 2.573 kwh/day
= 6.74 kwh/day
Panel Dimensions = (1 meter x 2 meter)
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Calculation
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Conclusion: In this experiment we learnt about the solar power system and also calculated
the efficiency of the solar panel which comes out to be 18.61%.
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