Solar cell basics
Solar cell basics
Converting solar energy to electricity via photovoltaic cells is one of the most exciting and practical scientific discoveries of the last several hundred years. The use of solar power is far less damaging to the environment than burning fossil fuels to generate power.
In comparison to other renewable energy resources such as hydro power, wind, and geothermal, solar has unmatched portability and thus flexibility. The sun shines everywhere.
These characteristics make solar power a key energy source as we move away from our fossil fuel dependency, and toward more sustainable and clean ways to meet our energy needs.
The sun is a powerful energy resource. Although very little of the billions of megawatts per second generated by the sun reaches our tiny Earth, there is more than enough to be unlimited in potential for terrestrial power production.
The sunlight that powers solar cells travels through space at 186,282 miles per hour to reach the earth 8.4 minutes after leaving the surface of the sun. About 1,368 W/M2 is released at the top of the earth's atmosphere. Although the solar energy that reaches the Earth's surface is reduced due to water vapor, ozone layer absorption and scattering by air molecules, there is still plenty of power for us to collect.
Harvesting photons for use in homes, factories, offices, vehicles and personal electronics has become practical, and economical, and will continue to increase in its importance in the energy supply equation.
In my opinion, the most exciting aspect of photovoltaic power generation is that it creates opportunities for the individual power consumer to be involved in the production of power. Even if it is only in a small way, you can have some control of where your energy comes from.
Almost anyone can set up a solar panel and use the power – independent of the grid and other "powers that be."
Batteries and super capacitors for the electronic devices that we use on a daily basis can be recharged by this natural and renewable energy resource. Doing so cuts down on pollution and makes life better for everyone. Practically every aspect of our lives will be touched in a positive way by the increasing use of solar electric power.
A solar cell is a solid state semiconductor device that produces DC (direct current) electricity when stimulated by photons. When the photons contact the atomic structure of the cell, they dislodge electrons from the atoms. This leaves a void which attracts other free available electrons. If a PN junction is fabricated in the cell, the dislodged photons flow towards the P side of the junction.
The result of this electron movement is a flow of electrical current which can be routed from the surface of the cell through electrical contacts to produce power. The conversion efficiency of a solar cell is measured as the ratio of input energy (radiant energy) to output energy (electrical energy).
The efficiency of solar cells has come a long way since Edmund Becqueral discovered the photovoltaic effect in 1839. Present research is proceeding at a fast clip to push the efficiencies up to 30% and beyond.
The efficiency of a solar cell largely depends on its spectral response. The wider the spectrum of light that the cell can respond to (the spectral response), the more power is generated. Research is ongoing to develop techniques and materials that can use more of the light spectrum and thus generate more power from each photovoltaic cell.
The reflectivity of the cell surface and the amount of light blocked by the surface electrodes on the front of the cell also affect the efficiency of solar cells.
Anti-reflective coatings on cells and the use of thin electrodes on the surface of cell faces help to reduce this loss of photonic stimulation. Another factor in cell efficiency is the operating temperature of the cell. The hotter a cell gets, the less current it produces.
Inherently, solar cells in use get hot, so it is important to have them mounted in such a way that they are cooled as much as possible to keep current production at its maximum.
Silicon is the most widely used material for solar cells today, though this is changing as thin film amorphous technologies are achieving greater efficiencies using materials such as gallium arsenide, cadmium telluride and copper indium diselenide.
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Our planets natural resources of non-renewable fossil fuel energy are fast diminishing and the harsh global warming effect is increasing every day. Solar energy is the most important invention that humans every made because it has enabled us to harness the power of sun to create a clean renewable energy source. The growth of the solar cells in the 19th century has taken on the most significance importance when we look at how important solar energy has become today.
Australian National University has developed new technology that reduces the cost of solar cells and may revolutionize solar energy. This is very exciting as the sun one of the few natural renewable energy sources that can cope up with human demands in the long run. At this stage of our global warming crisis solar power energy is looking like one the most important inventions of mankind.
The low energy photons are part of the infrared spectrum, the high energy photons are part of the ultraviolet spectrum and in between these two exists visible light of all colours.
1. Difference between crystal and amorphous? Daily to see the solid is divided into two major categories of non-crystalline and crystalline, non-crystalline arrangement of atoms within the material is not necessarily the law of the fracture when the fracture is random, such as plastic and glass, and called the crystal material, represent the natural shape of a regular polyhedron, with obvious edges and corners with the plane, the atom is in accordance with its internal law must line up neatly, s
Solar Cell Type Introduce The classification of solar cells Crystalline solar cell according to the state Department of membrane can be divided into crystalline and amorphous thin film system (hereinafter expressed as a-) two categories, while the former is further divided into single-crystalline and multi-crystalline.
In 2009, affected by the upcoming subsidy decline, the newly added installed capacity of Germany saw substantial growth, reaching 3.80 GW. It reached 1.50 GW in December 2009. In 2010, the installed capacity will continue to increase and even exceed 5.40 GW.
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arren and molten, the new planet earth first orbited the sun five to ten billion years ago. Even after the crust solidified and the depressions filled with water, this barrenness persisted. Chemical elements and simple compounds were randomly scattered on the surface. Organization of the elements into complex organic compounds was unknown.
At most sites, what is called run of river is the best mode of operation. This means that power is produced at a constant rate according to the amount of water available. Usually the power is generated as electricity and stored in batteries and can be tied to an existing PV or other system. The power can take other forms: shaft power for a saw, pump, grinder, etc. Both head and flow are necessary to produce power.
At most sites, what is called run of river is the best mode of operation. This means that power is produced at a constant rate according to the amount of water available. Usually the power is generated as electricity and stored in batteries and can be tied to an existing PV or other system. The power can take other forms: shaft power for a saw, pump, grinder, etc. Both head and flow are necessary to produce power.
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Anybody can make biodiesel. It's easy, you can make it in your kitchen -- and it's BETTER than the petro-diesel fuel the big oil companies sell you. Your diesel motor will run better and last longer on your home-made fuel, and it's much cleaner -- better for the environment and better for health.
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