SOLAR ENERGY UTILIZATION
ADVANTAGES OF SOLAR POWER ENERGY
- Renewable Energy Source. - Immensely Abundant. - Solar Technologies are Getting More Efficient. - Solar Panels Are Getting Cheaper. - Generates Minimal Greenhouse Gas Emissions.
DISADVANTAGES OF SOLAR POWER ENERGY
- Still Expensive for Households. - Weather Dependent. - Solar Power Plants Are Not the Most Environmentally Friendly Option.
2 Factors of Process of Scattering
- λ of the incoming radiation - the size of the scattering particle or gas molecule.
average distance between the Sun and the earth
1 astronomical unit (AU) = 1.496 x 10^11 m
two basic functions of solar cell
1) Absorb the incident solar radiation generating at least one hole pair for each photon 2) Separate and collect the electrons and holes such that the electrons accumulate at the negative pole while the holes accumulate at the positive pole. The separation potential must be as high as possible.
Types of PV Systems
1. Grid Connected Solar PV System 2. Stand-Alone / Off- grid Solar PV System 3. PV-Hybrid Systems 4. Grid-Tied Solar Systems With A Battery Backup
Technological parameter effects on the performance parameters of the real solar cells.
1. The solar size 2. Solar cell material 3. The thickness of the Si-solar cells 4. The spectral response of the solar cells 5. The Antireflection coating
FOUR MAIN TYPES OF SOLAR CONCENTRATOR SYSTEMS
1. parabolic trough, 2. power tower 3. linear Fresnel 4. dish
Diameter of the Sun
1.39 x 10^9 m
Amount of sun radiation
1.7 × 10^17 W
AM0 at about 70% of the radiation incident on the atmosphere transmitted to the earth.
135.3 mW/cm2
extraterrestrial irradiance
1353 W/m²
Solar Constant (G_sc)
1367 W/m²
a function of the incident wavelength of the photons and it is a material property.
ABSORPTION COEFFICIENT ALPHA
Normal type of fuse box provided with a domestic electricity supply and installation with the exception of additional breakers for inverter and/or filter connections.
AC Breaker Panel and Fuses
Formula of air mass (AM)
AM = 1/(cos θ )
process in which solar radiation is retained by a substance and converted into heat. creation of heat causes the substance to emit its own radiation. the absorption of solar radiation by substances in the Earth's atmosphere results in temperatures that get no higher than 1800° C.
Absorption
Processes of Converting Solar Energy into Electricity
Absorption of energy Photovoltaic conversion Combination of current from several cells Conversion of the resultant DC to AC
Include the use of photovoltaic systems, concentrated solar power and solar water heating.
Active Solar Technology
Solar power intensity after crossing one air mass perpendicular to the earth. represents the area under the spectral irradiance curve and amounts to 92.5 mW/cm2.
Air Mass 1, AM1
Solar power intensity without the effect of the atmosphere or ground surface
Air Mass Zero, AM0
atoms of the material have random order compared with their original sites in the single crystal.
Amorphous
- angle between the sun׳s rays and the normal on a surface
Angle of Incidence, θ
depends on a number of factors, such as duration of an uninterrupted power supply to the load when there is less or no radiation from the sun.
Bank sizing
- Known as Battery bank - Important element in any stand-alone PV system but can be optional depending upon the design. - Used to store the solar-produced electricity for night time or emergency use during the day. - Produces 20-30 % power loss due to heat
Batteries
can be of 12V, 24V or 48V and many hundreds of amperes in total.
Battery banks
To be available at the absence of the solar radiation, the electric energy produced by the array must be partly stored
Battery storage
Top 5 largest solar power plants in the world
Bhadla Solar Park, India Location: Rajasthan, India Installed Capacity: 2245 MW, 14000 acres Huanghe Hydropower Hainan Solar Park China Location: Qinghai province, China Installed Capacity: 2200 MW, 1390 acres Pavagada Solar Park, India Location: Karnataka, India Installed Capacity: 2050 MW, 13000 acres Benban Solar Park, Egypt Location: Aswan Governorate, Egypt Installed Capacity: 1650 MW, 9190 acres Tengger Desert Solar Park, China Location: Ningxia, China Installed Capacity: 1547 MW, 10625 acres
use mirrors or lenses to concentrate a large area of sunlight, or solar thermal energy, onto a small area.
CSP plants
- the power generated in solar power systems that use solar concentrators to convert solar energy into heat and then the produced heat is converted into power. - based on Brayton or Rankine cycles.
Concentrating solar power (CSP)
atoms are perfectly ordered in a three-dimensional array.
Crystalline
called Campbell-Stokes recorders o measure the amount of hours in the day throughout which the daylight is above a certain level (commonly 200 mw/cm2).
Daylight recorders
Solar radiation that reaches the Earth's surface after it was altered by the process of scattering.
Diffused Solar Radiation 𝐼d,c
Registers power measurement by solid-state current and voltage sensing devices; convert analog measured values into binary values that are displayed on the meter using liquid crystal display (LCD) readouts.
Digital electric meters
Sunlight reaching the Earth's surface unmodified by any of the atmospheric processes
Direct/Beam Solar Radiation 𝐼b,c
- called Kilowatt hour (kWh) meter - used to record the flow of electricity to and from the grid.
Electricity Meter
characterized by saturated covalent bonds where each atom is bonded to the neighboring atoms by four covalent bonds.
Elementary semiconductors
minimum energy required to break a bond and generate an electron hole (e-h) pair separates the free electrons from the free holes
Energy gap
the time of the year wherein the plane of Earth's equator passes through the geometric center of the earth roughly around 20 March and 23 September.
Equinox
Incident outside the earth's atmosphere On average, the extraterrestrial irradiance is ; This value varies by ±3% as the earth orbits the sun.
Extraterrestrial Radiation
known as a hybrid solar system An ideal solution for those who either don't have the space or finances available to install solar energy equipment. Prozides home battery storage can be use during power outages; makes these systems worth considering cost more to install than a typical grid-tied solar system due to the additional expense of a battery bank.
Grid-Tied Solar Systems With A Battery Backup
hotter regions with higher current densities than the surrounding regions in the diode.
Hot-spots
capable of generating about 1 or 2W of power approximately depends of the type of material used.
Individual small PV cell
- The most important part of any grid connected system. - Extracts as much DC electricity as possible from the PV array and converts it into clean mains AC electricity at the right voltage and frequency for feeding into the grid or for supplying domestic loads.
Inverter
The incident energy per unit area on a surface - determined by integration of irradiance over a specified time, usually an hour or a day.
Irradiation
composed of energy quanta called photons
LIGHT
an angle measured at the center of the Earth, between the Equator plane. - north or south - varies from 0° to 90°
Latitude, L
- angle at center of the Earth, between where you are and Greenwich - Can be measured either east or west and varies from 0° to 180
Longitude 'λ'
Shade on one panel will only affect that singular panel; much less impact on the system's overall performance.
Microinverter System
consists of long curved mirrors that concentrate sunlight on a liquid inside a tube that runs parallel to the mirror. The liquid heat is generally used to produce steam that drives a steam turbine.
PARABOLIC TROUGH
use fields of mirrors to concentrate sunlight on the top of central towers, in which the intense heat, generally carried by molten salts, boils water, and the steam then drives turbines.
POWER TOWER
interact with the electrons and atoms of the material.
PROTONS
Its function is the conversion of solar radiation into electricity; major unit in the system.
PV array
Combination of any two input sources; can be integrated with Diesel Generator, Wind Turbines, Bio-mass or any other renewable on non-renewable energy sources. Generally use battery bank to store energy output from the panels to accommodate a pre-defined period of insufficient sunshine; exceptional periods of poor weather.
PV-Hybrid Systems
Include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, a
Passive Solar Technology
Converts solar radiation into electricity directly. Made up of several photovoltaic solar cells.
Photovoltaic ( PV) system
2 ways of solar energy conversion
Photovoltaic Method Thermal Technologies
material is composed of crystallographic grains joined together by grain boundaries.
Polycrystalline
- primary component - converts the DC power produced by the PV array into AC power as per the voltage and power quality requirements of the utility grid
Power Conditioning Unit
According to the nature of the load, the generated electric power must be conditioned using DC/DC converters and DC/AC inverters.
Power conditioning circuits
occurs when small particles and gas molecules diffuse part of the incoming solar radiation in random directions without any alteration to the λ of the electromagnetic energy. reduce the amount of incoming radiation reaching the Earth's surface significant proportion of scattered shortwave solar radiation is redirected back to space.
Process of Scattering
measuring worldwide radiation
Pyranometer
measuring immediate radiation
Pyrheliometer
process where sunlight is redirect by 180° after it strikes an atmospheric particle; causes a 100 % loss of the insolation. reflectivity (albedo) of a cloud can range from 40 to 90 %.
Reflection
the basic element in a PV array. has the vital function of converting the solar radiation into electricity directly. To perform its function satisfactorily, it must have the highest possible conversion efficiency.
SOLAR CELL
- a unit array in the PV generator. - consists of solar cells connected in series to build the driving force and in parallel to supply the required current.
SOLAR CELL MODULE
- Obtained by capturing heat and light from the Sun -Considered a green technology
SOLAR ENERGY
The transfer of energy via electromagnetic waves, travel at the speed of light. The velocity of light in a vacuum is approximately 3 x 108 m/s. The time it takes light from the sun to reach the Earth is 8 minutes and 20 seconds. The input power source to the PV generators The sun emits electromagnetic radiations as a black body having a surface temperature of about 6000 K; because of the nuclear reaction running in it, where the sun is converting hydrogen into helium.
SOLAR RADIATION (I)
photovoltaic array will always produce a voltage output in sunlight; must be possible to disconnect it from the inverter for maintenance or testing.
Safety Switches and Cabling
a class of materials that have electrical conductivity between the metal and insulators. their electrical characteristics can be controlled by doping and by light.
Semiconductors
- is the angle between the line collinear with Sun's rays & the horizontal plane.
Solar Altitude Angle, 𝛼
- angle between a due south line and the projection of the location to the Sun line on the horizontal plane
Solar Azimuth Angle, 𝛼_s
- angle between the location to Sun line and the vertical at the location
Solar Azineth Angle, z
2 forms of energy tapping methods (Thermal Technologies)
Solar Concentration Heating and Cooling Systems
the energy from the sun, per unit time, received on a unit area of surface perpendicular to the direction of propagation of the radiation, at mean earth-sun distance, outside of the atmosphere.
Solar Constant (G_sc)
- angle made between the plane of the equator and the line joining the two centers of the earth and the sun. - The numerical value of latitude in which the sun is directly overhead at solar noon on any given day
Solar Declination δ
time required for the Sun to move 360°around the earth or 15°per hour
Solar Hour Angle, hs
Equal to the incident solar power/m2 / δ λ = [W /m2 / μm], where δ λ is the respective wavelength range in μm. It is given in W/m2 and is represented by the symbol G. The rate at which radiant energy is incident on a surface per unit area of surface.
Solar Irradiance (G)
- Device that converts light from the sun - Comprised of several individual solar cells which are themselves composed of layers of silicon, phosphorous and boron - Absorb the photons and in doing so initiate an electric current.
Solar Panels
Powered by a Rectifier AC source converts this power into a low voltage DC. Features low maintenance, lightweight design, and optional remote monitoring. Used with or without a transformer.
Solar Rectifier System
made of semiconductors as active material
Solar cells
the time of the year wherein the Sun reaches its most northerly/southerly path relative to the plane of Earth's equator. around 21 June & 21 December
Solstice
- Designed and sized to supply DC and/or AC electrical loads. - Called direct coupled systems because, the DC output of a PV module or array is directly connected to a DC load. - No electrical energy storage (batteries); because of that, the load only operates during sunlight hours
Stand-Alone / Off- grid Solar PV System
Odometer-type counting wheels that record power consumption at a service point by means of a rotating disc; connected to the counting mechanism.
Standard Service Meters
2 TYPES OF ELECTRIC METER
Standard Service Meters Digital electric meters
shade on one panel will affect electricity output for the entire system.
String Inverters
2 MAIN TYPES OF INVERTERS
String Inverters Microinverter System
Main energy source in our earth.
Sun Radiation
Visible light has a wavelength of between 0.40 to 0.71 micrometers (μm). The sun emits only a portion (44 %) of its radiation in this range. spans a spectrum from approximately 0.1 to 4.0 micrometers. About 7 % of the sun's emission is in 0.1 to 0.4 micrometers wavelength band (UV). About 48 % of the sun's radiation falls in the region between 0.71 to 4.0 micrometers (near infrared : 0.71 to 1.5 micrometers; far infrared: 1.5 to 4.0 micrometers).
Sun Radiation Spectrum
- angle between the normal to the surface from true south, westward is designated as positive.
Surface Azimuth Angle, Y
provides the positive charge
boron
HTF
heat transfer fluid
LFR stands for
linear Fresnel reflector
PD stands for
parabolic dish
PTC stands for
parabolic trough collector
provides the negative charge
phosphorous
particles of energy
photons
has an electron-filled valence band and an empty conduction band
semiconductor
made of crystals - give the highest efficiency made of amorphous materials - give the lowest efficiency.
solar cells
SPT stands for
solar power tower