Photovoltaic Effect

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solar array - photovoltaic effect - solar city
Photovoltaic effect is a direct conversion of light into electricity, which as the name implies (photo meaning "light" and voltaic meaning "electricity") and this means converting sunlight directly into electricity. That was the brief definition of the Photovoltaic Effect.


- Photovoltaic materials:

 In order to understand the Photovoltaic effect, we need to know the materials which photovoltaics are made of.
 Photovoltaic materials are special materials called semiconductors such as silicon, which is currently used most commonly.
In order to get the photovoltaic effect we add some impurities to silicon.

First type of silicon used:
Consider silicon with some atoms of phosphorous here and there, maybe one for every million silicon atoms. Phosphorous has five electrons in its outer shell, not four. It still bonds with its silicon neighbor atoms, but in a sense, the phosphorous has one electron that doesn't have anyone to hold hands with. These electrons, called free carriers. The resulting silicon is called N-type ("n" for negative) N-type doped silicon is a much better conductor than pure silicon.

Second type of silicon used:

Consider silicon is doped with the element boron, which has only three electrons in its outer shell instead of four, to become P-type silicon. Instead of having free electrons, P-type ("p" for positive) has free openings and carries the opposite (positive) charge.

So Photovoltaic materials used to get photovoltaic effect are P-type & N-type silicon.

- Photovoltaic energy:

photovoltaic effect - photovoltaic energy - solar city
Sunlight contains packets of energy called 'photons'. When the sunlight strikes the N-type silicon layer, the energy that photons carry makes some electrons free and they move. They move to the P-type layer causing electrical current in the circuit. The electrical energy that we get with photovoltaic effect is called photovoltaic energy.


- What are photovoltaic cells :

 Photovoltaic cells are the units which is connected together to form a solar panel and we can say that a photovoltaic cell is the building unit in the solar system which made of photovoltaic materials and makes a photovoltaic effect under the sun to give solar energy.


photovoltaic effect - what are photovoltaic cells - solar city


- Photovoltaic array:
Photovoltaic array is a combination of solar panels connected together.
Photovoltaic panel or module is a combination of solar cells which is connected together in series or in parallel and collected in one frame. While there are many brands on the market, there are essentially just three types of technologies involved in making a solar panel – monocrystalline, polycrystalline and thin film.

Photovoltaic cells are made of special materials called semiconductors such as silicon, which is currently used most commonly. - See more at: http://www.solar-city.net/2013/10/what-is-photovoltaic-effect_7.html#sthash.lXIq2P6v.dpuf
which as the name implies (photo meaning "light" and voltaic meaning "electricity"), convert sunlight directly into electricity. - See more at: http://www.solar-city.net/2013/10/what-is-photovoltaic-effect_7.html#sthash.lXIq2P6v.dpuf


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Home solar power systems - Photovoltaic systems

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home solar power systems - photovoltaic systems

 

Home solar power systems :

When we hear the phrase "Home solar power systems", all the applications which convert solar power to a useful power for our homes come in our imagination.
These applications could be "photovoltaic systems", "Solar water heaters", "solar cooker" and more...
But as we used in our homes, electricity can run everything. So most of us think about "photovoltaic systems" the first thing and we are going to cover "Photovoltaic systems" in this topic.

Consumption:

 When you decide going solar the first thing you'll need to know is your electric consumption and how much money you could save monthly if you used photovoltaic systems. You can read this topic "Average Electric Power Consumption" to know more.

Cost:

 Before deciding to spend thousands of dollars on a Photovoltaic system, It’s wise to evaluate how energy-efficient your home is, and how much your family’s lifestyle affects your energy usage. Without knowing this information, you really can’t determine the size of the Photovoltaic system that’s right for your home. You can read this topic "Size & Cost of photovoltaic system you'll need to cover your electrical consumption"


Photovoltaic systems:

 Solar Photovoltaic systems are technologies that convert the energy from sunlight into electrical energy. Residential solar Photovoltaic systems can offset much of your household's power needs, depending on the size of the system, your household's needs and your location.

Photovoltaic systems components:
Photovoltaic syestems components: panels, battery, inverter, charg

1. Solar panels:
   
solar cells, solar panels, solar module, solar array
Solar panels are the main parts in the photovoltaic systems as they contain the technology to convert the sunlight into electricity. Photovoltaic panel or module is a combination of solar cells which is connected together in series or in parallel and collected in one frame. While there are many brands on the market, there are essentially just three types of technologies involved in making a solar panel – monocrystalline, polycrystalline and thin film.
All of these kinds only could generate DC electrical power.
You can see more about photovoltaic (PV) effect, how do photovoltaic (PV) cells work, photovoltaic panels, Types of PV panels and Which type is more suitable with you. By visiting previous topic "What is photovoltaic effect, definitation and types of PV solar panels?"

 

2. Mounting frame:
Mounting frame is the frame where we mount our solar modules or panels, But what is the importance of it? - OK
In fact it's very important to know exactly the most efficient position and adjusting it's angel according to your location on the earth in order to collect the most amount of sunlight you can.
This topic could help you "Solar systems installation"

Photovoltaic panel or module is a combination of solar cells which is connected together in series or in parallel and collected in one frame - See more at: http://www.solar-city.net/2013/10/what-is-photovoltaic-effect_7.html#sthash.dZfSNUIY.dpuf

3. Charge controller:
It plays a vital role in regulating the voltage that enters the batteries in order not to cause failure.


4. Battery:
Batteries are the best method of storing energy from Photovoltaic systems for the periods when the sun is not shining. (This is for stand-alone or non -grid connected systems.)
Most of Batteries used in Photovoltaic systems generates typically 12 volts and their capacities are measured by the unit (amp.hours)
Deep cycle batteriesare available for golf carts, and include Industrial Chloride batteries. These batteries are the best choice for Photovoltaic systems as they can be discharged 80%. The golf cart batteries will last 3-5 years. There are some larger capacity deep cycle batteries that will last 7-10 years. Industrial Chloride batteries will last 15-20 years.


5. Inverter:
All applications and equipments in our homes uses Alternating current (AC) power, but solar panels generate Direct current (DC) also batteries store DC power. So inverters are used in photovoltaic systems in order to convert DC into AC and they are reliable and efficient. An inverter has a major cost of the photovoltaic system. It could start with 1000$.



Photovoltaic systems connection types:
Photovoltaic systems are generally classified according to their function and operational requirements and how the system is connected to other power sources and electrical loads. The two main types are "grid-connected or utility-interactive systems" and "stand-alone systems". Photovoltaic systems can be designed to provide DC and/or AC power service, can operate interconnected with or independent of the utility grid, and can be connected with other energy sources and energy storage systems.


Stand alone photovoltaic systems:

Stand alone photovoltaic systems
Stand-alone photovoltaic 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. These types of systems may be powered by a photovoltaic module only or wind energy or an engine-generator as an auxiliary power source in what is called a "PV-hybrid" system.
These photovoltaic systems requires
batteries to store power for the times when the sun is not shining.
Stand alone system or separate system can exist in a home that also has grid utility power as long as they are completely separated.

Grid connected "grid interface" photovoltaic systems:

Grid connected "grid interface" photovoltaic systems
 Grid interface photovoltaic systems are designed to operate in parallel with and interconnected with the electric utility grid.
The primary component in grid-connected photovoltaic systems is the inverter, or power conditioning unit (PCU). The PCU converts the DC power produced by the photovoltaic array into AC power suitable for the voltage and power quality requirements of the utility grid, and automatically stops supplying power to the grid when the utility grid is not energized.
A bi-directional interface is made between the photovoltaic system AC output circuits and the electric utility grid, typically at an on-site distribution panel or service entrance. This allows the AC power produced by the photovoltaic system to either supply home electrical loads, or to back-feed the grid when the photovoltaic system output is greater than the home load demand. At night and during other periods when the electrical loads are greater than the photovoltaic systems output, the balance of power required by the loads is received from the electric utility This safety feature is required in all grid-connected photovoltaic systems, and ensures that the photovoltaic systems will not continue to operate and feed back into the utility grid when the grid is down for service or repair.


Lifespan and maintenance:
Solar Electric systems last a long time depending on the amount of active use, or the amount of sunshine converted into electricity by the photovoltaic modules . Manufacturers will usually provide 20+ year warranty, but photovoltaic modules will likely last longer than that. The balance of system components, however, will have a shorter life. 
Without any moving parts, maintaining photovoltaic systems is relatively simple.
For grid-connected systems, minimal maintenance is required, including keeping the panels free of any dirties such as fallen leaves, bird droppings, etc.
For stand-alone systems, the batteries usually require the most maintenance.
Photovoltaic systems manufacturers will usually provide a 20+ year warranty on the Photovoltaic modules, and a 10-year warranty on the balance of system components.
Before deciding to spend thousands of dollars on a Photovoltaic system, It’s wise to evaluate how energy-efficient your home is, and how much your family’s lifestyle affects your energy usage. Without knowing this information, you really can’t determine the size of the Photovoltaic system that’s right for your home. - See more at: http://www.solar-city.net/2013/09/size-of-pv-panels-you-need-to-cover.html#sthash.487S6lQj.dpuf

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What is photovoltaic effect, definitation and types of PV solar panels?

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Photovoltaic systems- what is photovoltaic effect, definition and types of pv solar panels
- What is photovoltaic (PV) effect and how do photovoltaic (PV) cells work?
- What are photovoltaic panels?
- Types of PV panels.
- Which type is more suitable with your usage.

This is what we are going to cover in this topic of "Photovoltaic systems"

In previous topics of "photovoltaic systems" you might know "what exactly is your consumption of electricity" and "Cost and size for installing your new PV solar system". Whether you made the decision to go solar or not you still had to know more about Photovoltaic panels:


Photovoltaic Effect:

The solar cells that you see on everywhere are also called photovoltaic (PV) cells, which as the name implies (photo meaning "light" and voltaic meaning "electricity"), convert sunlight directly into electricity.
Photovoltaic cells are made of special materials called semiconductors such as silicon, which is currently used most commonly.

The silicon in a solar cell has impurities -- other atoms  mixed with the silicon atoms -- which changes the way things work a bit. Consider silicon with an atom of phosphorous here and there, maybe one for every million silicon atoms. Phosphorous has five electrons in its outer shell, not four. It still bonds with its silicon neighbor atoms, but in a sense, the phosphorous has one electron that doesn't have anyone to hold hands with. These electrons, called free carriers. The resulting silicon is called N-type ("n" for negative) N-type doped silicon is a much better conductor than pure silicon.
The other part of a typical solar cell is doped with the element boron, which has only three electrons in its outer shell instead of four, to become P-type silicon. Instead of having free electrons, P-type ("p" for positive) has free openings and carries the opposite (positive) charge.





  How do photovoltaic solar cells work?

Sunlight contains packets of energy called 'photons'. When the sunlight strikes the n-type silicon layer, the energy that photons carry makes some electrons free and they move. They move to the p-type layer causing electrical current in the circuit. The device that we want to run will be contact to the Front contact and Bach contact. Look at figure below.
How do photovoltaic solar cells work? Photovoltaic Effect:

What are Photovoltaic (PV) panels?



What are Photovoltaic (PV) panels?
Photovoltaic panel or module is a combination of solar cells which is connected together in series or in parallel and collected in one frame called solar panel or solar module.
A solar array as shown is a combination of solar panels connected together in one frame.







Types of PV panels:

While there are many brands on the market, there are essentially just three types of technologies involved in making a solar panel – monocrystalline, polycrystalline and thin film (amorphous).
The info-graph blow will be more efficient to know difference between them:
Photovoltaiv PV solar panels types: Monocrystalline solar cells are made out of silicon ingots, which are cylindrical in shape. To optimize performance and lower costs of a single monocrystalline solar cell, four sides are cut out of the cylindrical ingots to make silicon wafers, which is what gives monocrystalline solar panels their characteristic look. A good way to separate mono- and polycrystalline solar panels is that polycrystalline solar cells look perfectly rectangular with no rounded edges. Polycrystalline Depositing one or several thin layers of photovoltaic material onto a substrate is the basic gist of how thin-film solar cells are manufactured. They are also known as thin-film photovoltaic cells (TFPV). The different types of thin-film solar cells can be categorized by which photovoltaic material is deposited onto the substrate:      Amorphous silicon (a-Si)     Cadmium telluride (CdTe)     Copper indium gallium selenide (CIS/CIGS)     Organic photovoltaic cells (OPC) Outstanding performance in cooler conditions. Excellent life span / longevity. Usually come with a 25yr warranty. Slightly better performance in hotter conditions (lower heat derating coefficient) - Expected lifespan is less than crystalline panels.  - Optimal efficiency in hot weather, less effective in cooler conditions.

Which type of PV panels is more suitable with your usage:

Remember: the best solar panels may be different depending on your needs and location!

To make this decision you must study the three types first and take these factors in consideration:
- Your location ( solar intensity)
- Space or area you have.
- Temperature.
- Economical view.

Now the decision is yours.

We never forget to recommend you that having a clean world and powerful energy sources is the responsibility of all of us. So as you are here you must play your role by sharing this topic with your friends. We know that your dream is to see our world as a large solar city.


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Size & Cost of PV panels you need to cover your electricity consumption.

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Size of pv panels you need to cover your electricity consumption

Economical view:

 A solar Photovoltaic power system is a technology that converts the energy from sunlight into electrical energy. Residential solar Photovoltaic systems can offset much of your household's power needs, depending on the size of the system ,your household's needs and your location.
Before deciding to spend thousands of dollars on a Photovoltaic system, It’s wise to evaluate how energy-efficient your home is, and how much your family’s lifestyle affects your energy usage. Without knowing this information, you really can’t determine the size of the Photovoltaic system that’s right for your home.
 So the fist thing you need to know is your average monthly consumption of Electrical energy and we mentioned how to get it in a previous topic of "photovoltaic systems".
But let's talk about me for example: my average monthly consumption is about 200kWh and this cost me about ( 200 * 0.2$ = 40$ per month).

Ok- Let's see if it is economical for me to setup a PV solar system? and what area I need to install it?

Solar radiation data:

As we know the amount of solar radiation that you can collect varies depending on your location, the season and all over the day. It's complicated to make a full report about this and you can find these details in previous topics "Solar radiation and The seasons", but we are talking now about average as we are looking at the matter with economical view.
But is there any other way to know nearly the solar power per square meter amount without owning a solar power meter? Of course yes. But you can't get an exact number with it. You can get a range.
Look at the annual world solar energy map below.
- See more at: http://www.solar-city.net/2013/08/solar-radiation-data-necessary-to-go.html#sthash.NbtpHpLP.dpuf
There are many ways to know solar energy per square meter that sun can provide you at your location like buying a solar power meter, but as you are just talking about average you can use one of the online tools available. But you can't get an exact number with it. You can get a range.
Look at the annual world solar energy map below.
Solar Radiation
But is there any other way to know nearly the solar power per square meter amount without owning a solar power meter? Of course yes. But you can't get an exact number with it. You can get a range.
Look at the annual world solar energy map below.
- See more at: http://www.solar-city.net/2013/08/solar-radiation-data-necessary-to-go.html#sthash.NbtpHpLP.dpuf
But is there any other way to know nearly the solar power per square meter amount without owning a solar power meter? Of course yes. But you can't get an exact number with it. You can get a range.
Look at the annual world solar energy map below.
- See more at: http://www.solar-city.net/2013/08/solar-radiation-data-necessary-to-go.html#sthash.NbtpHpLP.dpuf
You can see that each color represents a range of energy that the place collects all over the year with the unit (KWh/m2) per year.
and to get more accurate number I recommend you to use this online tool.
If you have a problem with understanding any thing feel free to let your comment. - See more at: http://www.solar-city.net/2013/08/solar-radiation-data-necessary-to-go.html#sthash.NbtpHpLP.dpuf
You can see that each color represents a range of energy that the place collects all over the year with the unit (KWh/m2) per year.
To get more accurate number I recommend you to use this online tool.
If you have a problem with getting your annual solar radiation feel free to let your comment with your exact location.
Again about me: in my location my annual solar radiation is about 2200kWh/m^2.
So monthly solar radiation energy could be about: 2200 / 12 = 183.3 let's say 180kWh/m^2


Efficiency of Photovoltaic cells will reduce power:

Unfortunately we can't convert all of this amount of energy into electrical power as Photovoltaic cells have an efficiency range from 10% to 20% according to type. Let's say the efficiency is 15% so power that I can get will be: 180 * 0.15 = 27 let's say it's 25 kWh/m^2 monthly.

Size and cost:

Now about me again to get 200kWh monthly I'll need: 200 / 25 = 8 m^2 of PV panels.
about cost to evaluate cost I need to get daily energy consumption first: 200/30(days per month) = about 7kwh/day.
a general rule of thumb for calculating the cost of a PV system is $3.50 per installed watt.
so this could cost me 7000 * 3.5 = 24,500$
Notice that my consumption is considered very high.

Now I'll need 8 meter square of area on my roof (out of shade) and 24,500$ to cover my electrical consumption which is 200kWh every month.
so I'll save about 50$ per month (remember that electricity cost increases with time)
so I'll need 24,500 / 50 = 490 month = 41 years to cover It's cost.

Now follow the steps above and try to fill the table below for you:


If you faced any trouble feel free to ask in a comment.
In the coming topic of "photovoltaic systems" we are going to tell you more about PV solar panels types.

We never forget to recommend you that having a clean world and powerful energy sources is the responsibility of all of us. So as you are here you must play your role by sharing this topic with your friends. We know that your dream is to see our world as a large solar city.

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Average electric power consumption bill.

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average electric power consumption bill

This topic will lead you to know the amount of power you need to get from a Photovoltaic solar system in order to start going solar, but why we change to Photovoltaic solar systems?
The perfect answer to this question is to say: "To decrease pollution and get renewable energy bla bla bla" ,but to be honest with ourselves most of people see problems in a personal way or exactly in an economical view. Anyway we start our survey and take the economical view in the consideration.

When you want to know your electric power consumption, you need also to know if your are going to calculate it your self or you already are on the electric grid and can read the consumption on
the
Electricity meter.

If you are already connected to electricity grid and have an electricity meter, all you need is to notice the monthly change in the reading of the electricity meter. Also you already get a bill monthly and pay for electricity.(you can tell us how much you pay monthly)

you will get the reading with the unit (kwh) and if you want to change it to (Kwatt) :
[average monthly change (kwh) / 730 = average monthly change (Kwatt)](730 is the total hours per month)

 What if you don't have an electricity meter or you are not connected to electricity grid or you are making your personal project in a remote place?  So you have to calculate your consumption according to machines and devices you need to run.(summation of watts)
Picture below shows the consumption of some devices if you don't find it written on your device.

electric power consumption -photovoltaic survey-solar city

In the upper picture you must notice that the consumption is in watts not Kwatts so you will need to divide the result by 1000 to get the result in Kwatts.

- To know how much money you will save per month :
Kilo wattage   x   hours used  x  price per kWh  =   cost of electricity

For example lets say that we leave a 100watt bulb running continuously (730 hours monthly) and  you're paying 15¢/kWh. Your cost to run the bulb all month is 0.1 x 730 x 15¢ = $10.95.
(price per kWh changes from country to other so you need to ask about it yourself but in 2013 it is about 0.16EUR or 0.2USD per kWh)

You can't always trust the wattage printed on the device, because many devices don't use the full listed wattage all the time but we are talking about average also we keep in mind more usage for dramatically situations.

Now you can calculate the average kWatts you will need and money you can save, but you must ask yourself now : how many watts can I get from the sun per meter square?
The answer of this question will be covered in the next topic "Size of PV panels you need to cover your electricity consumption."
Size of PV panels you need to cover your electricity consumption. - See more at: http://www.solar-city.net/2013/09/size-of-pv-panels-you-need-to-cover.html#sthash.t1HKA8zn.dpuf
of photovoltaic systems.

We never forget to recommend you that having a clean world and powerful energy sources is the responsibility of all of us. So as you are here you must play your role by sharing this topic with your friends. We know that your dream is to see our world as a large solar city.

We never forget to recommend you that having a clean world and powerful energy sources is the responsibility of all of us. So as you are here you must play your role by sharing this topic with your friends. We know that your dream is to see our world as a large solar city. - See more at: http://www.solar-city.net/2013/08/solar-radiation-data-necessary-to-go.html#sthash.AvQOep2W.dpuf
We never forget to recommend you that having a clean world and powerful energy sources is the responsibility of all of us. So as you are here you must play your role by sharing this topic with your friends. We know that your dream is to see our world as a large solar city. - See more at: http://www.solar-city.net/2013/08/solar-radiation-data-necessary-to-go.html#sthash.AvQOep2W.dpuf

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Solar Radiation Data necessary to go Solar

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when you decide going solar it's easy to pay for a specialist to install your solar device, but if you want to do it yourself, you are now in the right place.
there are two issues to know as a start.
1st: what is solar radiation and what data you will need? Answered in this topic.

2nd: position and best angle for solar panels or solar device to install? see here

simply...to answer the first question (solar radiation data). we need first to know What is solar radiation?
The Earth receives energy from the sun by way of radiated energy. This radiated energy is carried by tiny particles having no mass called photons. Photons behave like waves and, as such, have a characteristic wavelength, frequency, and energy. It is the energy of these photons that is used in photovoltaic cells to excite electrons so that an electrical current can be produced.

All energy carried by photons is referred to as electromagnetic (EM) energy and spans all possible values for wavelength and frequencies. Ranges of this spectrum—from shortest wavelength to longest—are referred to as gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves, and radio waves.


However, different types of stars produce differing amounts of energy in each region of the spectrum. Our sun emits more photons in the visible light and surrounding regions than in any other part of the EM spectrum. This phenomenon may be why our eyes have evolved to see that part of the EM spectrum and not microwaves, gamma rays, or any of the other wavelengths that are emitted at lower intensities by our sun.


The Earth’s atmosphere protects us from the higher-energy forms of light, such as ultraviolet rays. In fact, the existence of life on Earth would be far less likely if these more damaging forms of energy were more abundant. The terrestrial spectrum in Left Figure describes the light that actually reaches the Earth’s surface after passing through the atmosphere. Notice that there are various wavelengths in which the number of photons is greatly reduced as compared to the space solar spectrum. This difference is due to photons being absorbed by atmospheric gases, the best known being ozone (O3), which absorbs higher-energy (lower-wavelength) ultraviolet light below 400 nm. Photons with wavelengths near 900, 1100, and 1400 nm are absorbed by water vapor in the atmosphere.

Now, how can we measure solar power (solar flux)? It's measured by the unit (Watt/m2) or (Btu/ft2*h) depending on the unit used commonly in your country.
To measure it - there is a digital device called (Solar power meter)
It's shown in the Left figure and it has also other shapes but this one is common.
by using solar power meter you can measure solar power per square meter The sun gives at the moment and place you are now.(Watt/m2) Of course the amount of power changes by time all over the day.

If you want to be a professional it's recommended to own one - It's easy to get one online from a trusted market like Amazon and we recommend This solar power meter to you.
But is there any other way to know nearly the solar power per square meter amount without owning a solar power meter? Of course yes. But you can't get an exact number with it. You can get a range.
Look at the annual world solar energy map below.

You can see that each color represents a range of energy that the place collects all over the year with the unit (KWh/m2) per year.
and to get more accurate number I recommend you to use this online tool.
If you have a problem with understanding any thing feel free to let your comment.

We never forget to recommend you that having a clean world and powerful energy sources is the responsibility of all of us. So as you are here you must play your role by sharing this topic with your friends. We know that your dream is to see our world as a large solar city.

Read More »