A Brief on solar energy and its uses…….

Sun is a continuous source of energy.The energy produced by the sun is renewable type and is unending.

It is the reason why there is survival of the entire universe.

The constant and continuous energy released by the sun is known as solar energy. The energy is transmittedby a process known as RADIATION. Out of all the energythat is being concentrated on the Earth only a 70% is being received by the Earth due to its albedo.

Advantages and Disadvantages• Advantages

• All chemical and radioactive polluting byproducts of the thermonuclear reactions remain behind on the sun, while only pure radiant energy reaches the Earth.

• Energy reaching the earth is incredible. By one calculation, 30 days of sunshine striking the Earth have the energy equivalent of the total of all the planet’s fossil fuels, both used and unused!

• Disadvantages• Sun does not shine consistently.• Solar energy is a diffuse source. To harness it, we

must concentrate it into an amount and form that we can use, such as heat and electricity.

• Addressed by approaching the problem through: 1) collection, 2) conversion, 3) storage.

Using a device known as solar cell the solar energy is being converted to usable electrical energy that is DC in nature.

What is a Solar Cell ?

A solar cell is a semiconductor device which convertselectromagnetic radiation into electrical signals.It is a device which generates electricity directly from Sun’sradiation by means of the photovoltaic effect so it is also calledPhotovoltaic cell.

In order to generate useful power, it is necessary to connect anumber of cells together to form a solar panel, also known as aphotovoltaic module.

The nominal output voltage of a solar panel is usually 12Volts, and they may be used singly or wired together into an array.

The number and size required is determined by the availablelight and the amount of energy required.

The Photoelectric Effect

• The photoelectric effect relies on the principle that whenever light strikes the surface of certain metals electrons are released.

• In the p-n junction the n-type wafer treated with phosphorus has extra electrons which flow into the holes in the p-type layer that has been treated with boron.

• Connected by an external circuit electrons flow from the n-side to create electricity and end up in the p-side.

Working of solar cells

WWKJRHKJHWKJEHREWLRKJWERJcted to the solar cell , electrons flow in the circuit and the current is generated.

When the solar cell is placed in the influence of heat energy anelectron hole pair is being created by the p-type and n-type semiconductors.And thus the current is generated and is used By the respective device as per requirement and efficiency.

Different Types of Solar Cells

Amorphous Solar Cell

Crystalline Solar Cell

Types of Crystalline Solar Cells

Single Crystal Solar cells

Polycrystalline Solar Cells

Multicrystaline solar cell

Monocrystaline solar cell

Efficiency of Solar Cell

• Efficiency of a Solar cell is the ratio of the electrical power output to the light input.

• The Efficiency can be increased by using an anti-reflection coating on the thin heavily doped surface.

• The maximum efficiency so far is 18.7%.

How Does A Cell Become A Module?

• A solar cell is the basic building block of a PV system.

• A typical cell produces .5 to 1V of electricity.

• Solar cells are combined together to become modules or if large enough, known as an array.

• A structure to point the modules towards the sun is necessary, as well as electricity converters, which convert DC power to AC.

• All of these components allow the system to power a water pump, appliances, commercial sites, or even a whole community.

Solar car

Solar heater Solar lights

Applications

Solar cars

Solar water heaters Street lights

Pros and Cons of electricity production

• PV can be designed for a variety of applications

• No noise or air pollution

• Require minimal maintenance and have long service life times.

• Power can be either centralized in individual homes or distributed by electrical companies.

Photovoltaic (PV) systems—have very little impact on the environment, making them one of the cleanest power-generating technologies available .Solar power produces no air pollution. •Solar power produces no greenhouse gases, so it does not contribute to global warming.

Pros and Cons of electricity productionContd…

Life

• Average 20-30 years

• Efficiency decrease 1% a year.

• Research on manufacturing and output efficiency and recycling ongoing.

• Payback or energy break even - 15 years.