Saturday 14 January 2017

What is roof top solar panel?

What is rooftop solar photo voltaic cell/panel?
As the name defined it is a photo voltaic system that generate electricity by its solar panels mounted on the rooftop of a residential or commercial building. Here the panel are supported by a stand or structure.The no of panels connected as per total power requirement/demand.The rooftop system can be off line or online with grid. The capacity can be installed in residential area 5 to 20 KW while in commercial purpose 100 KW or more.


IMAGE OF ROOFTOP PANEL

The various components of solar rooftops:-
Photo voltaic modules,
 Mounting systems,
Cables and trays,
Solar inverters .




Advantage of solar rooftops:-
Reduces requirement of land for solar Power.
It reduces need for additional transmission infrastructure
Power can be available in remote area.
Savings in transmission and distribution losses.
No requirement of additional land.
Local employment generation.

Tuesday 10 January 2017

What is solar thermal power plant and its working?


Working principle of Solar thermal power plant:-
It works in the principle of conversation of  heat energy of sun's rays in to steam by utilizing to high temperature fluid. The fluid is then circulated through pipes so that it can transfer its heat to water and produce steam. The steam is directed through a steam turbine which convert heat energy of steam into mechanical energy into mechanical energy , which drives a generator to produce electricity. it is the one type of renewal energy used now a days.

Types of solar thermal power plant:-


A) Parabolic troughs.

Parabolic troughs are used in the longest operating solar thermal power facility in the world,A parabolic trough collector has a long parabolic-shaped reflector that focuses the sun's rays on a receiver pipe located at the focus of the parabola. The collector tilts with the sun as the sun moves from east to west during the day to ensure that the sun is continuously focused on the receiver.Because of its parabolic shape, a trough can focus the sun from 30 times to 100 times its normal intensity (concentration ratio) on the receiver pipe located along the focal line of the trough, achieving operating temperatures higher than 750°F.The solar field has many parallel rows of solar parabolic trough collectors aligned on a north-south horizontal axis. A working (heat transfer) fluid is heated as it circulates through the receiver pipes and returns to a series of heat exchangers at a central location. Here, the fluid circulates through pipes so it can transfer its heat to water to generate high-pressure, superheated steam. The steam is then fed to a conventional steam turbine and generator to produce electricity. When the hot fluid passes through the heat exchangers, it cools down, and is then recirculated through the solar field to heat up again.The power plant is usually designed to operate at full power using solar energy alone, given sufficient solar energy. However, all parabolic trough power plants can use fossil fuel combustion to supplement the solar output during periods of low solar energy.

B) Solar dishes:-

Solar dish/engine systems use concentrating solar collectors that track the sun, so they always point straight at the sun and concentrate the solar energy at the focal point of the dish. A solar dish's concentration ratio is much higher than a solar trough's concentration ratio, and it has a working fluid temperature higher than 1,380°F. The power-generating equipment used with a solar dish can be mounted at the focal point of the dish, making it well suited for remote operations or, as with the solar trough, the energy may be collected from a number of installations and converted into electricity at a central point.

The engine in a solar dish/engine system converts heat to mechanical power by compressing the working fluid when it is cold, heating the compressed working fluid, and then expanding the fluid through a turbine or with a piston to produce work. The engine is coupled to an electric generator to convert the mechanical power to electric power.

Solar power tower:-
A solar power tower, or central receiver, generates electricity from sunlight by focusing concentrated solar energy on a tower-mounted heat exchanger (receiver). This system uses hundreds to thousands of flat, sun-tracking mirrors called heliostats to reflect and concentrate the sun's energy onto a central receiver tower. The energy can be concentrated as much as 1,500 times that of the energy coming in from the sun.Energy losses from thermal-energy transport are minimized because solar energy is being directly transferred by reflection from the heliostats to a single receiver, rather than being moved through a transfer medium to one central location, as with parabolic troughs.This is promising technology for large-scale grid-connected power plants. 




Friday 9 September 2016

How the solar cell works.

How the solar cell works.




 Solar cells or (P V) photovoltaic cells which convert the light energy of sun into directly electrical energy. It is one of the best renewal energy available in the world. ​ Working of solar cell- The working principle of a solar cell same as principle of P-N junction silicon diode .The cell consists of a semiconductor device of P-N junction. Silicon is used for solar cell material. Here are generally two junctions of P-N .One is high concentration of holes known as P- type and another is high concentration of electron known as N- type material. Sun light consists of plenty of photons .When the sun light falls on the P-N junction, due to excess of electron in N- type it try to diffuse with holes of P-type where as excess holes from P-type try to diffuse with electron of N-type. Due to exchange of electron and holes across the junction current flows through the junction .The dc EMF are generated with P-terminal is known as positive and N-terminal is known as negative. The EMF generated is depending upon the intensity of sun light. No of cells are connect in series to form a string and several strings are connect in parallel to form a module and several modules are connect in parallel to collect final electricity. The power generation depend on the number of cells connect.​ 


The website www.mnre.gov.in give complete details of update news of renewable energy .

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