Solar Power Systems

How Solar Energy is being converted into Eletrical

2008-07-16T03:11:00.000-07:00

Today let's have a brief overview of methodology involved in the conevrsion of Solar Energy to Electrical Power. First of all, deifintions for some of the common terminology.
Photovoltaic energy :
Photovoltaic energy is the conversion of sunlight into electricity.
Photovoltaic cell :
A photovoltaic cell, commonly called a solar cell or PV, is the technology used to convert solar energy directly into electrical energy. A photovoltaic cell is a nonmechanical device usually made from silicon alloys.
Technology involved :
Sunlight is composed of photons, or particles of solar energy. These photons contain various amounts of energy corresponding to the different wavelengths of the solar spectrum. When photons strike a photovoltaic cell, they may be reflected, pass right through, or be absorbed. Only the absorbed photons provide energy to generate electricity. When enough sunlight (energy) is absorbed by the material (a semiconductor), electrons are dislodged from the material's atoms. Special treatment of the material surface during manufacturing makes the front surface of the cell more receptive to free electrons, so the electrons naturally migrate to the surface.
When the electrons leave their position, holes are formed. When many electrons, each carrying a negative charge, travel toward the front surface of the cell, the resulting imbalance of charge between the cell's front and back surfaces creates a voltage potential like the negative and positive terminals of a battery. When the two surfaces are connected through an external load, electricity flows. The photovoltaic cell is the basic building block of a photovoltaic system. Individual cells can vary in size from about 1 centimeter (1/2 inch) to about 10 centimeter (4 inches) across. However, one cell only produces 1 or 2 watts, which isn't enough power for most applications. To increase power output, cells are electrically connected into a packaged weather-tight module. Modules can be further connected to form an array. The term array refers to the entire generating plant, whether it is made up of one or several thousand modules. The number of modules connected together in an array depends on the amount of power output needed.
The performance of a photovoltaic array is dependent upon sunlight. Climate conditions (e.g., clouds, fog) have a significant effect on the amount of solar energy received by a photovoltaic array and, in turn, its performance. Most current technology photovoltaic modules are about 10 percent efficient in converting sunlight. Further research is being conducted to raise this efficiency to 20 percent.
The success of PV in space generated commercial applications for this technology. The simplest photovoltaic systems power many of the small calculators and wrist watches used everyday. More complicated systems provide electricity to pump water, power communications equipment, and even provide electricity to our homes.

Why Windows Vista is unique :

2008-07-07T20:48:00.000-07:00

We have summarized some of the unique features of Windows Vista, which definitely pave your mind about the verstylity of the Operating System. Let's have a look.
Windows Aero: The new hardware-based graphical user interface is named Windows Aero, which is an acronym for Authentic, Energetic, Reflective, and Open. The new interface is intended to be cleaner and more pleasing than those of previous Windows, including new transparencies, live thumbnails, live icons, and animations, thus providing a new level of eye vision. One of the drawback is that Laptop users report however that battery life is shortened with the feature enabled.
Windows Shell: The new Windows shell is significantly different from Windows XP, offering a new range of organization, navigation, and search possibilities. Windows Explorer's task pane has been removed, integrating the relevant task options into the toolbar. A "Favorite links" pane has been added, enabling one-click access to common directories. The address bar has been replaced with a breadcrumb navigation system. The preview pane allows users to see thumbnails of various files and view the contents of documents. The details pane shows information such as file size and type, and allows viewing and editing of embedded tags in supported file formats. The Start menu has changed as well; it no longer uses ever-expanding boxes when navigating through Programs. The word "Start" itself has been removed in favor of a blue Windows Orb (also called "Pearl").
Instant Search (also known as search as you type) : Windows Vista features a new way of searching called Instant Search, which is significantly faster and more in-depth (content-based) than the search features found in any of the previous versions of Windows.
Windows Sidebar: A transparent panel entitled to the side of the screen where a user can place Desktop Gadgets, which are small applets designed for a specialized purpose (such as displaying the weather or sports scores). Gadgets can also be placed on other parts of the desktop.
Windows Internet Explorer 7: New user interface, tabbed browsing, RSS, a search box, improved printing, Page Zoom, Quick Tabs (thumbnails of all open tabs), Anti-Phishing filter, a number of new security protection features, Internationalized Domain Name support (IDN), and improved web standards support.
Windows Media Player 11 :
Windows Media Player 11, a salient feature of Microsoft's program for playing and organizing music and video. New features in this version include word wheeling (or "search as you type"), a new GUI for the media library, photo display and organization, the ability to share music libraries over a network with other Vista machines.
Backup and Restore Center: Includes a backup and restore application that gives users the ability to schedule periodic backups of files on their computer, as well as recovery from previous backups. Backups are incremental, storing only the changes each time, minimizing disk usage. It also features Complete PC Backup (available only in Ultimate, Business, and Enterprise versions).
Windows Mail: A replacement for Outlook Express that includes a new mail store that improves stability, and features integrated Instant Search. It has the Phishing Filter like IE7 and Junk mail filtering that is enhanced through regular updates via Windows Update.
Windows Calendar is a new calendar and task application.
Windows Photo Gallery, a photo and movie library management application. It can import from digital cameras, tag and rate individual items, adjust colors and exposure, create and display slideshows and burn slideshows to DVD.
Windows DVD Maker, a companion program to Windows Movie Maker that provides the ability to create video DVDs based on a user's content.
Windows Media Center, which was previously exclusively bundled as a separate version of Windows XP, known as Windows XP Media Center Edition, has been incorporated into the Home Premium and Ultimate editions of Windows Vista.
Games and Games Explorer: Games included with Windows have been modified to showcase Vista's graphics capabilities. New games are Chess Titans, Mahjong Titans and Purble Place. A new Games Explorer special folder holds shortcuts and information to all games on the user's computer

Solar Energy : Living Solution to Energy Crisis

2008-07-04T02:11:00.000-07:00

Despite the energy crisis and soaring Oil prices, a considearable attention is not going to be diverted to the utiliztion of easy to use Solar energy. Lets have a look to the basic concepts in this regard and after that discuss some possible technologies to utilize this enegry.
Solar Energy is the heat and light radiated from the Sun that drives Earth's climate and supports life. Solar technologies make controlled and efficient utilization of this energy resource. Some of the common solar technologies include photovoltaics which converts solar energy into electrical energy, concentrating solar thermal devices or various experimental technologies.
Before going into details of any of the solar technologies, let us have a brief overview of the significance of solar energy and also how vital is it for our common life.
Earth continuously receives 174×1015 Watts of incoming solar radiation at the upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by the atmosphere, oceans and land masses. After passing through the atmosphere, the insolation spectrum is mostly split between the visible and infrared ranges with a small part in the ultraviolet. The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850 x 1021 Joules per year. The point to be noted here is the worldwide electricity consumption was approximately 567 x 1017 Joules in 2005.
Solar power technologies convert sunlight into electricity using photo voltaic, concentrating solar thermal devices, or various experimental technologies. PV has mainly been used to generate power for small and medium-sized applications, from the calculator powered by a single solar cell, the solar powered watch to off-grid homes powered by a photovoltaic array. For large-scale generation, multi-megawatt PV plants are becoming more common. Completed in 2007, the 14 MW power station in Clark County, Nevada and the 20 MW site in Beneixama, Spain are characteristic of the trend toward larger photovoltaic power stations in the US and Europe.
A solar cell which is also called photo voltaic (PV) cell is a device that converts light into direct current using the photoelectric effect. The first solar cell was constructed by Charles Fritts in the 1880s. Although the prototype selenium cells converted less than 1% of incident light into electricity, both Ernst Werner von Siemens and James Clerk Maxwell recognized the importance of this discovery. Following the fundamental work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the silicon solar cell in 1954. These early solar cells cost 286 USD/watt and reached efficiencies of 4.5-6%.
The high cost of solar cells limited terrestrial uses throughout the 1960s. This changed in the early 1970s when prices reached levels that made PV generation competitive in remote areas without grid access. Early terrestrial uses included powering telecommunication stations, off-shore oil rigs, navigational buoys and railroad crossings. These and other off-grid applications have proven very successful and accounted for over half of worldwide installed capacity until 2004.
Germany has become the leading PV market worldwide since revising its Feed-in tariff system. Installed PV capacity has risen from 100 MW in 2000 to approximately 4,150 MW at the end of 2007. Spain has become the third largest PV market after adopting a similar feed-in tariff structure in 2004, while France, Italy, South Korea and the US have also seen rapid growth recently due to various incentive programs and local market conditions.
Storage is an important issue in the development of solar energy because modern energy systems usually assume continuous availability of energy. Solar energy is not available at night, and the performance of solar power systems is affected by unpredictable weather patterns; therefore, storage media or back-up power systems must be used.

Apple Launches iPhone 3G

2008-07-02T00:10:00.000-07:00

Apple's new mobile device features sound improvements, which includes a more attractive price tag that will likely ignite demand

Almost a year after its beginning with its first wireless handset, the iPhone, Apple launched a state of the art second version of the device, the iPhone 3G.

Salient Features :

Introduced by Apple CEO Steve Jobs in a June 9, the iPhone 3G has a number of salient features, some of the major are listed below,
• iPhone 3G has very competitive price. It will sell for $199 for an 8GB version and $299 for a 16GB version, which is on average 33% less from a year ago when the first devices sold.
• The new phone derives its name from the faster Internet downloads available on advanced, or third-generation (3G), wireless networks. It downloads Web pages as much as 36% faster than comparable phones from Nokia and Palm.
• The new phone also has a unique feature that lets users know their location using GPS satellites.
• This version of the iPhone is more attractive to business users. These include the ability to read documents from Microsoft Office, including documents in Word, spreadsheets in Excel, and PowerPoint presentations.
• Another new feature is a service called MobileMe, an expansion of Apple's existing .Mac Web service, which offers hosted e-mail, online storage, and other services for users of Apple's Macintosh computers.
• Improvements over the original device include improved audio quality on phone calls

The iPhone 3G will be available in 22 countries beginning July 11, and will eventually be sold in 70 countries in all.

Welcome to the Technology Heaven

2008-07-01T22:06:00.000-07:00

Dear Visitor,

You are most welcome to the heaven of technical resources, where you can find all the stuf related to techincal hot topics, guidelines to the beginners and usefull information for the experts.

Today's world has severe demand and thurst of knowledge, and it can be told without any hesitation that knowledge is the only power which is leading, ruling and reshaping this world. The people, communities and the nations which are sound in technical literacy and are aware as well as well prepared to deal with the upcoming challanges, are prosperious and are well progressing, which is quite obvius and according to the law of nature, "Survival for the fittest".

Here is a minor and quite sensible try to update the visitors and meet the demands related to knowledge, skill and innovation. On these pages one can find a large variety of topics, editorials, discussions, books and a number of related items on scientific issues in general and technology and engineering, in particular.

Any sugessions, updates and info which may help our cause are more than welcome.

Keep in touch and updated.

Kind Regards,