Solar Altitude

Solar Altitude

Earth Rotation Around the Sun

As a result of the earth rotating around the sun, the sun appears to move between the Tropic of Cancer 23.45 degree North in the Northern Hemisphere and the Tropic of Capricorn 23.45 degree South in the Southern Hemisphere.

When the sun is over either of the two tropics, its is known as solstice and when the sun is over the equator is known as Equinox.

The Sun reaches the Tropic of Cancer at the Northern Solstice (June 21st) and the Tropic of Capricorn at the Southern Solstice (December 22nd). The Sun crosses the equator at the equinoxes in March 21st and September 23rd. This means that the altitude of the Sun at solar noon varies a total 46.9 degree during the calendar year.

The formula for calculating the altitude of the sun when its is over the equator (ỿ_e) for a specific altitude is:

ỿ_e=90 - Latitude (in degrees)

The formula for calculating the altitude of the when it is over the tropics (ỿt), i.e. either the Tropic of Cancer or Tropic of Capricorn, is:

                                    ỿt=90 - Latitude (in degrees) ± 23.45 degrees

Whether to use the + or - is dependent on the hemisphere (Northern or Southern) where you are located and over which "tropic" (either Cancer or Capricorn) you wan to determine the sun's altitude. when applying this formula it is assumed that you are facing the equator, for example, facing south in the Norther Hemisphere.

As a rule of thumb, when the latitude is in the same hemisphere as the tropics you add 23.45 degrees and when the latitude is in the opposite hemisphere as the tropic you subtract 23.45 degree.

For Delhi (which is outside if the tropics), the sun will never be directly overhead, as depicted in the figure below. its important to understand where the sun will actually be in the sky when positioning solar modules, as you need to determine if any obstacles will shade the modules.

In the tropics it is important that the sun can be in both the northern and the southern skies as shown in the figure below. If you are in the tropics it is important to determine the amount of time, and at what time of the year, the sun is in the northern and southern directions. This is to ensure that objects like trees and buildings will not shade the solar modules.

In the tropics, the sun is in the southern part of the sky at solar noon during Summer. In Mumbai for example, for the period from May 16th to July 28th, the sun will actually be in the northern part of the sky. Therefore you willneed to look for potential obstacles that could cause shading in both the Southern and Northern directions.

Table below provides information on altitude of the sun for various latitude in the northern hemisphere tropics (i.e. India). This table also provides the altitude of the two equinoxes and also indicated when the sin is in the northern sky with respect to the altitude. This can help locate possible obstacles that will shade the modules at various times of the year.

Defining The Position Of The Sun

Defining The Position Of The Sun

The location of the sun is specified by two angles:

• Altitude (γ) the angle between the sun and the horizon (in degree).
• Azimuth (α) the angle between north and the sun's position. Similar to using a compass where the direction being faced is measured as a number of degrees from north. The altitude and azimuth of the sun are constantly changing throughout the day and year as the Earth rotates on its axis (day/night) and around the sun (seasonal variation).

Altitude

Altitude refers to the angle between the sun and horizontal (or ground), and is always an angle between 0 degree and 90 degree. The sun is higher in the sky in summer and lower in the sky in winter due to the neutral tilt of the earth with respect to the sun as the Earth orbits the sun throughout the year.

Azimuth 

The sun moves from east to west across the sky through the day. The angle between north and the point of the compass where the sin is position is called the  azimuth angle. In general, the azimuth is measured clockwise going from 0 degree (true north) to 359 degree. East is 90 degree, South is 180 degree and West is 270 degree.

In the diagram, altitude and azimuth are shown with points of the compass.

Variation in the altitude and azimuth are shown in the table along with time of days and time of years for Delhi. The table provides the time for solar noon, when the sun is at the highest altitude for the day, midway between sunrise and sunset. In India this is typically between 12 pm an 1 pm.

Defining The Position Of The Sun

Defining The Position Of The Sun

The location of the sun is specified by two angles:

• Altitude (γ) the angle between the sun and the horizon (in degree).
• Azimuth (α) the angle between north and the sun's position. Similar to using a compass where the direction being faced is measured as a number of degrees from north. The altitude and azimuth of the sun are constantly changing throughout the day and year as the Earth rotates on its axis (day/night) and around the sun (seasonal variation).

Altitude

Altitude refers to the angle between the sun and horizontal (or ground), and is always an angle between 0 degree and 90 degree. The sun is higher in the sky in summer and lower in the sky in winter due to the neutral tilt of the earth with respect to the sun as the Earth orbits the sun throughout the year.

Azimuth 

The sun moves from east to west across the sky through the day. The angle between north and the point of the compass where the sin is position is called the  azimuth angle. In general, the azimuth is measured clockwise going from 0 degree (true north) to 359 degree. East is 90 degree, South is 180 degree and West is 270 degree.

In the diagram, altitude and azimuth are shown with points of the compass.

Variation in the altitude and azimuth are shown in the table along with time of days and time of years for Delhi. The table provides the time for solar noon, when the sun is at the highest altitude for the day, midway between sunrise and sunset. In India this is typically between 12 pm an 1 pm.

Some Electrical Basics For Solar Power Plant

Electrical Basics

In this post I'll be telling some electrical basics which should be know before getting started with solar power plant project.

Polarity

A lack of electrons (positive charge) or an excess of electrons (negative charge) results in a material assuming a charge. When the electrons distribution in equal, the material will be electrical neutral. Changing the balance of electrons produces a potential difference, which can then be applied to a change by rubbing a piece of plastic, or it may be the chemical energy stored in a battery which gives rise to the positive and negative polarity.

A charged battery with a large potential difference discharges, until the potential difference is zero

 Type of Materials

1. Conductors

A conductor is a material in which electrons can move easily from one atom to another. Generally, all

metals are conductors with silver being the best conductor and copper second. The purpose of a conductor is to allow an electric current (electrons) to flow from a source to a load with the least amount of opposition. For example, the wire connecting a torch globe to the battery of the torch are conductors. Copper is generally used because it cost less than silver, although long transmission lines are now likely to be aluminium, which is only slightly behind copper as a conductor but is lighter and cheaper.

    2.  Insulators

Insulators are materials in which the electrons do not move easily, but are move tightly bound in their atomic orbits. These materials resists the flow of electrical current from areas where it is not required or where it might prove dangerous. An example would be the coating/covering on cables.

An insulator is able to store an electric charge because it resist the movement of electrons within its structure. An insulator used to store a charge is called a dielectric. Dry air is a dielectric, an anyone who has received a static electricity shock can confirm. On days when the air is humid, static electricity drains away through the air to ground.

    3.  Semi - Conductors
Materials which area neither insulator nor conductors, but exhibits some of the properties of both, are called semi conductors. Examples of semi conductors materials are carbon, silicon and germanium. Germanium was very popular in early manufacture but now has largely been replace by silicon. the microchip industry, as well as the solar cell industry, is a large consumer of silicon.

Volts and Potential Difference

Potential refers to the possibility of doing work. When energy is applied to a material to cause a change in its state of charge (that is, we give it potential) it is given the ability to do work as it attempts to return to the neutral state. One unit if charge, called a Coulomb (C) has a quantum number of 6.27 x 10^18 electrons. The difference between between two charge states is called the Potential Difference (PD) and is measured in units called Volts.

The volt (V) is the unit that measures the work needed to move one unit of charge between two points. Briefly, when 1 Joule of energy is needed to move 1 coulomb of charge two points, there is a potential difference between the two points of 1 volt. Voltage  is the potential difference two points.

Voltage is sometimes referred to as Electromotive Force or EMF and given the symbol (ξ) but the standard for a potential difference is V, either for a generating source (e.g. solar cell) or voltage drop across a passive component (e.g. resistor).

Parts Used In Completed Solar PV system......

A Solar PV System:

A Solar PV System may comprise of may parts and those parts may comprise of some more parts.

First we are going know what are the major key components of the system which makes it to convert solar energy into useful electrical energy.

 

COMPONENTS:

Photovoltaic Panels.

Solar Inverts.

PV Mounting Structure.

Batteries.

 

Photovoltaic Panels:

This part is THE most important part of the system. Panels are the parts which absorbs solar energy from the sun and converts into electrical energy right away at the panel junction box. Lets talk about how these solar panels convert energy of sun into useable electrical energy. Solar panels comprise of may small solar cells which are made from silicon. A solar cell is a solid state electrical device converts the sun light into electrical energy by photovoltaic effect. These solar cells can be made up from many type of substances. The major cells which we generally use are made up of silicon. Let me give you a brief on type of substances solar cells.

1. Amorphous Silicon solar cell (a-Si)
2. Bio-hybrid solar cell
3. Buried contact solar cell
4. Cadmium telluride solar cell (CdTe)
5. Concentrated PV cell (CVP and HCVP)
6. Copper indium gallium selenide solar cells (CI(G)S)
7. Crystalline silicon solar cell (c-Si)
8. Dye-sensitized solar cell (DSSC)
9. Gallium arsenide germanium solar cell (GaAs)
10. Hybrid solar cell
11. Luminescent solar concentrator cell (LSC)
12. Micro-morph (tandem-cell using a-Si/μc-Si)
13. Mono-crystalline solar cell (mono-Si)
14. Multi-junction solar cell (MJ)
15. Nano-crystal solar cell
16. Organic solar cell (OPV)
17. Perovskite solar cell
18. Photo-electrochemical cell (PEC)
19. Plasmonic solar cell
20. Plastic solar cell
21. Polycrystalline solar cell (multi-Si)
22. Polymer solar cell
23. Quantum dot solar cell
24. Solid-state solar cell
25. Thin film solar cell (TFSC)
26. Wafer solar cell,  

 

These are the solar cell that can be used in solar panels. The solar cells which are widely used in the market or by companies or by individual are:

Poly- Crystalline.

Mono- Crystalline.

Amorphous.

Thin Film.

 

Poly-Crystalline:

 It is also called polysilicon or poly-Si, is a high purity, polycrystalline form of silicon, used as a raw material by the solar photovoltaic and electronics industry. These cells are effectively a slice cut from a block of silicon, consisting of a large number of crystals. They have a speckled reflective appearance and again you can you see the thickness of the slice. These cells are slightly less efficient and slightly less expensive than mono-crystalline cells and again need to be mounted in a rigid frame.

Mono- Crystalline:

These cells are cut from a single crystal of silicon- they are effectively a slice from a crystal.
In appearance, it will have a smooth texture and you will be able to see the thickness of the slice. These are the most efficient and the most expensive to produce. They are also rigid and must be mounted in a rigid frame to protect them.

Amorphous:

These cells are manufactured by placing a thin film of amorphous (non crystalline) silicon onto a wide choice of surfaces. These are the least efficient and least expensive to produce of the three types. Due to the amorphous nature of the thin layer, it is flexible, and if manufactured on a flexible surface, the whole solar panel can be flexible.One characteristic of amorphous solar cells is that their power output reduces over time, particularly during the first few months, after which time they are basically stable. The quoted output of an amorphous panel should be that produced after this stabilization.

Thin Film:
A thin-film solar cell, also called a thin-film photovoltaic cell, is a second generation solar cell that is made by depositing one or more thin layers, or thin film of photovoltaic material on a substrate, such as glass, plastic or metal.Thin-film has always been cheaper but less efficient than conventional c-Si technology. However, they significantly improved over the years, and lab cell efficiency for CdTe and CIGS are now beyond 21 percent, outperforming multi-crystalline silicon, the dominant material currently used in most solar PV systems.

Lets Talk About Photovoltaic Effect:
The photovoltaic effect is the creation of voltage or electric current in a material upon exposure to light and is a physical and chemical phenomenon. The standard and obvious photovoltaic effect is directly related to the photoelectric effect, though they are different processes. When the sunlight or any other light is incident upon a material surface, the electrons present in the valence band absorb energy and, being excited, jump to the conduction band and become free. The chemical bonds of the material are vital for the process to work, as crystallized atoms are ionized and creates a chemical electric imbalance, driving the electrons. These highly excited, non-thermal electrons diffuse, and some reach a junction where they are accelerated into a different material by a built-in potential (Galvani potential). This generates an electromotive force, and thus some of the light energy is converted into electric energy.

 

 

 

 

 

All Right! New Topic Types of Solar Power Plants Use By People.......

Types of Solar Power Plants

Countries all over the world have decided to have solar power plants installed. People are getting conscious about saving the environment and this led them to study about energy of sun and its usefulness and its financial feasibility. There are many different kinds of solar power plants which can be installed. It is possible to make use of solar power plants in an active and passive manner. A solar power plant can be called active when the energy from the sun is converted directly into a useable form which can be used for powering all kinds of appliances that are present in the house. Passive use of solar energy takes place when houses and building have been created in such a manner that they get the maximum exposure to the rays of the sun.

There are many different kinds of solar power plants. They include the Photovoltaic Solar Energy Plant, Solar Thermal Energy Plant and Concentrating Power Plant.

 

Photovoltaic Solar Energy Plant:

The electricity produced by this plant is the substitute of our regular gird electricity. Photovoltaic cells or PV cell or solar panels or solar modules etc. captures the energy of the sun and generates the electricity. This process is clean and simple and it does not involve injecting any kind of smoke or harmful chemicals into the atmosphere. A lot of companies and individuals have installed solar power plant in there home premises so that they can derive maximum amount of energy from them and also reduce their dependence on the traditional forms of electricity.

 

Solar Thermal Energy Plant: A solar thermal energy plant will be used for creating solar generated heaters which can be used for heating water and also as an indoor heating system. Thermal cells will be used to capture the energy which has been generated by the sun and then convert it into heat energy. It is also possible to make use of this energy for cooking purposes and also for drying clothes. Low temperatures can be used for heating water as well as swimming pools. Medium heat is used for heating up the inside of homes as well as office buildings. High temperatures will help in generating the electricity which is needed for everyday uses in homes and offices.

 

Concentrating power plant – The method of functioning of these solar power plants is similar to that of the photovoltaic solar energy plants. The extra addition in these concentrating power plants is that they make use of mirrors and lenses in order to capture energy from the rays of the sun. The light from the sun will be directed towards the photovoltaic cells and they will be converted into heat energy. Usually very big companies make use of these concentrating power plants for utilizing solar energy.

 

The presence of solar power plants in many parts of the world has made it possible for the energy from the sun to be utilized in the right manner. They help in reducing the consumption of electricity to a large extent.

Solar Energy Benefits Continued...

Here are some benefits of solar energy.

 

Solar Power helps to slow/stop GLOBAL WARMING:

Global warming threatens the survival of human society, as well as the survival of countless species living on plant EARTH. Luckily, decades or even centuries of research have led to efficient solar panel systems that create electricity without producing global warming pollution. Solar power is now very clearly one of the most important solutions to the global warming crisis.

 

Solar Power Provides Energy Independence:

Similar to the energy boost, solar power provides the great benefits of energy independence. Again, the FUEL for solar panels cannot be bought or monopolized. Its is free for all of us. Once you have solar panels on your rood, you have an essentially independent source of electricity that is all your. This is important for Individuals, but also for cities, countries, and even companies. Two days back I read about Ukraine's clean-tech initiatives and projects. I discovered that Ukraine in recent years has saved approximately $3 billion in reduced oil and gas imports from Russia, thanks to the solar power plants which is IMPRESSIVE.

 

Now people Its Time for jobs from solar YES!

As a source of energy, solar power is a job-creating powerhouse. Money invested in solar power creates two to three times more jobs than money invested in coal or natural gas. This is shown in sample chart below:

 

Some More Benefits or Advantages are listed below:

• Solar energy is not only sustainable, it is renewable and this means that we will never run out of it. It is a natural source of power as it is possible to generate electricity.
• The creation of solar energy requires little maintenance. Once the solar panels have been installed and are working at maximum efficiency there is only a small amount of maintenance required each year to ensure they are in working order.
• They are a silent producer of energy. There is absolutely no noise made from photovoltaic panels as they convert sunlight into usable electricity.
• There are continual advancements in solar panel technology which are increasing the efficiency and lowering the cost of production, thus making it even more cost effective.
• During operation solar electricity power plants produce zero emissions.