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Solar Panel
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Solar Power
What is solar power?
Solar power uses Photovoltaic technology.
Photovoltaic technology converts sunlight into electricity
It is emerging as a major power source due to its numerous environmental and economic benefits and proven reliability.
Benefits of solar power?
Environmental Benefits: As PV generates electricity from light, PV produces no air pollution or
hazardous waste.
Economic and Social Benefits: ➢ Sunlight is free and abundant. ➢ Photovoltaic systems allows us to generate electricity and store it for use when needed. ➢ It creates jobs and strengthens the economy. ➢ It frees us from uncertainties and foreign oil dependence.
This energy source is free, clean and highly reliable.
Photovoltaic (PV) systems
PHOTOVOLTAIC SYSTEM
A complete system includes different components
that should be selected taking into consideration
your individual needs, site location, climate and
expectations.
TYPES OF SYSTEM
Stand Alone – Off grid Modules, charge controller, batteries, and may or may not have an inverter which converts DC power to A/c power
Grid Tie – Grid connected Modules, and inverter connected to the power grid
Hybrid – Grid connected with batteries Modules, grid-tie inverter, and batteries for storage when the
grid is unavailable
Stand Alone – Off Grid Systems
Stand-alone PV systems are designed to operate independent of the electric utility grid, and are generally designed and sized to supply certain DC and/or AC electrical loads.
For systems with no battery the energy is used immediately; only works when it's sunny
Grid Tie – Grid Connected Systems
Grid Tie System is the simplest and most cost effective way to connect PV modules to regular utility power. Grid-Connected systems can supply solar power to your home and use utility power as a backup.
Hybrid– Grid Connected with Batteries
If utility power is reliable and well maintained in your area, and energy storage is not a priority, you don't necessarily need a battery. But if the utility power goes down, even if there is solar, the PV system will be off for the safety of the utility workers. .
MAJOR SYSTEM COMPONENTS
PV Modules or Panels or Array
Charge controller
Battery charger
Inverter
Load
Available Cell Technologies
Single-crystal or Mono-crystalline Silicon
Polycrystalline or Multi-crystalline Silicon Thin film
Ex. Amorphous silicon or Cadmium Telluride
Monocrystalline Silicon Modules
Most efficient commercially available module (11% - 14%) Most expensive to produce Circular (square-round) cell creates wasted space on module
Polycrystalline Silicon Modules
Less expensive to make than single crystalline modules Cells slightly less efficient than a single crystalline (10% - 12%)Square shape cells fit into module efficiently using the entire space
Amorphous Thin Film
Most inexpensive technology to produce Metal grid replaced with transparent oxidesEfficiency = 6 – 8 %Can be deposited on flexible substrates Less susceptible to shading problems Better performance in low light conditions that with crystalline modules
PV CELLS
PV CELLS
❑ The layers have been doped with boron on one side and phosphorous on the other side, producing surplus of electrons on one side and a deficit of electrons on the other side. When the wafer is bombarded by sunlight, photons in the sunlight knock off some of excess electrons, this makes a voltage difference between the two sides as the excess electrons try to move to the deficit side. In silicon this voltage is .5 volt
PV CELLS
Metallic contacts are made to both sides of the semiconductor. With an external circuit attached to the contacts, the electrons can get back to where they came from and a current flows through the circuit. This PV cell has no storage capacity, it simply acts as an electron pump. The amount of current is determined by the number of electrons that the solar photons knock off.
LIMITATION WITH SINGLE PV CELL
Solar cell has a limitation that it can not produce much electricity.
In order to generate useful power, it is necessary to connect a number of cells together in series or in parallel.
INTERNAL CONNECTION OF PV CELLS
PV MODULE
A PV module consists of many PV cells wired in parallel to increase current and in series to produce a higher voltage. 36 cell modules are the industry standard for large power production.
PV PANELS
PV panels include one or more PV modules assembled as a pre-wired, field-installable unit.
PV ARRAY
A PV Array consists of a number of individual PV modules or panels that have been wired together in a series and/or parallel to deliver the voltage and amperage a particular system requires. An array can be as small as a single pair of modules, or large enough to cover acres.
DESIGN OF PV ARRAY
SOLAR PANEL DIMENSIONS
HOW TO WIRE A SOLAR PANEL
There are three types of wiring configurations to Solar Panel:
Series wiring
Parallel wiring
And a combination of the two known simply as series/parallel wiring.
SERIES WIRING
To wire any device in series you must connect the positive terminal of one device to the negative terminal of the next device
Voltage in a series circuit is additive
Current stays the same.
SERIES CONNECTION
12volts 350 AH
PARALLEL WIRING
To wire any device in parallel you must connect the positive terminal of the first device to the positive terminal of the next device and negative terminal of the first device to the negative terminal of the next device.Voltage in a parallel circuit stays the same. Current is additive.
PARALLEL CONNECTION
Series/Parallel Circuits
A Series/parallel circuit is simply two or more series circuits that are wired together in parallel.
SERIES /PARALLEL CONNECTION
SOLAR CHARGE CONTROLLER
The most basic function of a controller is to prevent battery over charching.
If batteries are allowed to routinely overcharge, their life expectancy will be dramatically reduced.
A controller will sense the battery voltage, and reduce or stop the charging current when the voltage gets high enough
SOLAR CHARGE CONTROLLER
BATTERY CHARGER
Batteries accumulate excess energy created by your PV system and store it to be used at night or when there is no other energy input.
The battery's capacity for holding energy is rated in amp-hours: 1 amp delivered for 1 hour = 1-amp hour
TYPES OF BATTERY
➢Lead Acid Batteries
➢Deep-Cycle battery
➢VRLA battery (valve-regulated lead–acid
battery)
➢ Absorbed glass mat (AGM) battery
➢ Gel battery
INVERTER
The batteries in your PV systems store direct current (DC) power which can be used for certain applications but most of the conventional household appliances use alternative current (AC) power. The Inverter converts low voltage DC into higher voltage AC.
INVERTER SIZING
The input rating of the inverter should never be lower than the total watt of appliances.
The inverter must have the same nominal voltage as your battery.
The inverter size should be 25-30% bigger than total Watts of appliances.
INVERTER SIZING
In case of appliance type is motor or compressor then inverter size should be minimum 3 times the capacity of those appliances and must be added to the inverter capacity to handle surge current during starting.
TYPES OF INVERTERS
• Square Wave Inverters
• Modified Sine Wave Inverters
• True Sine Wave Inverters
Solar Inverters
• Grid tie inverters
INVERTER
INVERTER
LOAD
Load – is electrical appliances that connected to solar PV system such as lights, radio, TV, computer,refrigerator, etc.
How does solar power work?
How does solar power work?
PV Module or Array convert the sunlight into
electricity.
PV modules generate DC electricity.
Controller regulate the DC power.
Battery stores the DC signal.
The inverter transforms DC power into AC
electricity.
Solar system (PV) calculation anddesign
Each panel is rated by its DC output power. Currently the best commercial solar panel
(PV) efficiency is around 17.4%.
Solar panels are normally 12V DC output. In large solar panel 24V or 48V DC output also seen.
SOLAR PV SYSTEM SIZING
To figure out what size solar panel, batteries, charge controller and inverter you need, follow the simple steps below.
1. Determine power consumption demands Determine the Watts required by each of the
appliances
➢ Let's assume you have a 100 watt device that you want to power with free solar energy.
SOLAR PV SYSTEM SIZING
2. Calculate total Watt-hours per day for each appliance used
➢ Estimate the hours per day that each appliance will be used.
Let's assume that you want to power for 10 hours
each night. 100 Watts x 10 hours = 1,000 Watt hours. That is the total energy you will need.
ENERGY LOST IN THE SYSTEM
Wiring and connection losses about 10%
Losses in the battery about 20%
Total losses around 30% so the panel will need to produce enough Wh/day for the load plus enough to cover the losses. So it will have to produce about 130% of the energy required by the load
To calculate the Wh/d needed from the panel, multiply the load Wh/d times 1.3
SOLAR PV SYSTEM SIZING
Multiply the total appliances Watt-hours per day times 1.3 (the energy lost in the system) to get the total Watt-hours per day which must be provided by the panels.
Total load= 1,000 Watt hours*1.3 =1300Watt hours So the 1300Watt-hours per day which must be
provided by the panels.
HOW TO CALCULATE THE SIZE OF SOLAR PANELS
2. Now calculate what size solar panel you will need. Based
on a ten hour day of light, the calculation is simple:
If Sunlight is for 10 hrs in a day
1,300 Watt hours / 10 hours sunlight = 130 Watt solar panel.
HOW TO CALCULATE THE SIZE OF BATTERY
3. Calculate what size batteries you need. 1,300 Watt hours divided by 12 Volts =108 Amp Hours of reserve battery power.
1,000 / 12 = 108
An average marine deep cycle battery will work well here. Select a larger size battery to be sure, say 120 Amp hours capacity.
HOW TO CALCULATE THE SIZE OF CHARGE CONTROLLER
4. To figure what size solar charge controller is
needed, take your solar panel wattage, which is 130 watts divided by 12 Volts. 130 / 12 = 10.8 Amps.
Always go larger, in this case use a 12 Amp solar charge controller.
HOW TO CALCULATE THE SIZE OF INVERTER
5. Calculate what size inverter is needed. That's the easy part. You need to power a 130 Watt load, so select an inverter that has at least 130 Watts continuous power rating.
Best Place For Solar Panels?
South Facing roof, adequate spaceNo shading (time of year, future tree growth)Roof structure, condition
DISADVANTAGES OF SOLAR PANEL
Less efficient and costly equipment.Reliability depends upon location. Environment Impact on PV cells.Part Time
Bibliography
http://www.solarhome.org/infowhatissolarpower.htmlhttp://www.wisegeek.org/what-is-solar-power.htm#http://www.scientificamerican.com/article.cfm?id=how-does-solar-power-workhttp://www.solartechnologies.com/cm/About-Solar-Power/how-does-solar-power-work.htmlhttp://science.howstuffworks.com/environmental/energy/solar-cell.htmhttp://cleantechnica.com/2011/10/07/how-does-solar-energy-work-how-solar-power-works/http://www.ehow.com/facts_7298775_do-need-solar-energy_.htmlhttp://ezinearticles.com/?Why-Should-We-Use-Solar-Energy?&id=1911019http://www.motherearthnews.com/Renewable-Energy/Solar-Power-Potential.aspshttp://www.nationalatlas.gov/articles/people/a_energy.html