Most of the time, when the electrical power gets interrupted due to a heavy downpour or a severe storm or any other reason, the reliable source of power when you require it the most is the power inverter. Power inverter is designed to answer these power outages and pose as a reliable and economic alternate source of electricity. That is why, the power inverters have enjoyed great popularity since their introduction in the market.

Power inverters are designed to convert direct current to alternating current. Most of the power inverters work by converting 12 Volt DC power into 110 volts AC. With the use of power Inverters you can run household appliances from a car or any other DC source in areas where there is no electricity. Power inverters are available in two categories – The True Sine Wave Power Inverters and the Modified Sine Wave Power inverters.

Of these the True sine wave power inverters provide utility grade power but are expensive and can power almost anything including laser printers and fax machines. The sine wave power inverter is most suitable to operate higher-end electronic equipment which can be damaged by other inverters. On the other hand, the Modified sine waves are the most common types of power inverters available today. Like its counterpart, this inverter can sufficiently power most household appliances and power tools. It is more economical compared to the true sine wave inverter, but may ask for certain compromises with some loads such as microwave ovens, laser printers, clocks and cordless tool chargers.

Power inverters are widely used for large assortment of applications, from small power supplies for a computer to large industrial applications to transport bulk power. One of the most widely used applications of Power Inverters include running television sets, microwaves and other household appliances and charging cell phones, laptops from a car’s cigarette lighter outlet and running power tools from a 12 volt battery on jobsites where electricity is not available.

If you are looking forward to buy a power inverter, remember that most of your household electrical devices will run perfectly on both the type of wave form. Most of the users who are using a power inverter to run a laptop, a/c cell phone charger, fan, or camera agree that a modified-sine wave power inverter that operates through the cigarette lighter socket is the easiest to use. While you buy a power inverter it is suggested to choose an inverter that is rated under 300 watts when using the 12-volt cigarette lighter socket found in most vehicles. This is because after reaching 300 watts of draw on the inverter, the fuses in your car might blow off. Such power inverters are a great choice for dashboarders who would like an easy solution to power their devices. It has only one outlet, but since plugging it into a 12 volt socket is all that is required for operation. This little inverter can supply 140 watts of continuous operation and has a built-in surge protector.

In countries such as Sweden, biogas is used to power trains. A biogas run train operates between Vaestervik and Linkoeping. The train is generated with energy that is derived from sewage and animal waste. The reason why Sweden has adopted the gas as a form of energy for its large motor vehicle industry is that the gas has been shown to generate less carbon dioxide emissions compared to other forms of diesel such diesel. The country produces the gas from alcoholic beverages that have been confiscated by other agencies. Most industries also concentrate the Methane gas that is found in biogas through biogas upgrader to standards such as natural gas. The resulting product known as biomethane is then used in the local energy distribution centers and in the pipeline industries. Further, biomethane is compressed and concentrated where it is used in the transport industries to power vehicles.

Other investors such as Bates transformed their cars in order to power them with biogas energy. Short documentaries that were produced in early 1974 show the simple benefits and process of powering cars using biogas. The documentary showed such gas being used to power vehicles for periods as long as seventeen years. In countries such as India, biogas is used to generate a gas known as gober gas. Gobar gas is a form of biogas that is made from animal waste. It is also made using various household plants. In other countries such as Pakistan, the government offers about 50% funds that are used in the creation of gas chambers. The flammable methane energy gas that is generated from the process is usually smokeless and odorless. This makes it quite economical in environmental sustenance. Due to this, the gas is largely used in the motor vehicle industries to power vehicles making true the assertion that biogas could be the fuel that will be used in powering most vehicles in the near future.

SunCatchers. (Credit: Image courtesy of Sandia National Laboratories)

Stirling Energy Systems (SES) and Tessera Solar recently unveiled four newly designed solar power collection dishes at Sandia National Laboratories’ National Solar Thermal Test Facility (NSTTF). Called SunCatchers™, the new dishes have a refined design that will be used in commercial-scale deployments of the units beginning in 2010.

“The four new dishes are the next-generation model of the original SunCatcher system. Six first-generation SunCatchers built over the past several years at the NSTTF have been producing up to 150KW [kilowatts] of grid-ready electrical power during the day,” says Chuck Andraka, the lead Sandia project engineer. “Every part of the new system has been upgraded to allow for a high rate of production and cost reduction.”

Sandia’s concentrating solar-thermal power (CSP) team has been working closely with SES over the past five years to improve the system design and operation.

The modular CSP SunCatcher uses precision mirrors attached to a parabolic dish to focus the sun’s rays onto a receiver, which transmits the heat to a Stirling engine. The engine is a sealed system filled with hydrogen. As the gas heats and cools, its pressure rises and falls. The change in pressure drives the piston inside the engine, producing mechanical power, which in turn drives a generator and makes electricity.

The new SunCatcher is about 5,000 pounds lighter than the original, is round instead of rectangular to allow for more efficient use of steel, has improved optics, and consists of 60 percent fewer engine parts. The revised design also has fewer mirrors — 40 instead of 80. The reflective mirrors are formed into a parabolic shape using stamped sheet metal similar to the hood of a car. The mirrors are made by using automobile manufacturing techniques. The improvements will result in high-volume production, cost reductions, and easier maintenance.

Among Sandia’s contributions to the new design was development of a tool to determine how well the mirrors work in less than 10 seconds, something that took the earlier design one hour.

“The new design of the SunCatcher represents more than a decade of innovative engineering and validation testing, making it ready for commercialization,” says Steve Cowman, Stirling Energy Systems CEO. “By utilizing the automotive supply chain to manufacture the SunCatcher, we’re leveraging the talents of an industry that has refined high-volume production through an assembly line process. More than 90 percent of the SunCatcher components will be manufactured in North America.”

In addition to improved manufacturability and easy maintenance, the new SunCatcher minimizes both cost and land use and has numerous environmental advantages, Andraka says.

“They have the lowest water use of any thermal electric generating technology, require minimal grading and trenching, require no excavation for foundations, and will not produce greenhouse gas emissions while converting sunlight into electricity,” he says.

Tessera Solar, the developer and operator of large-scale solar projects using the SunCatcher technology and sister company of SES, is building a 60-unit plant generating 1.5 MW (megawatts) by the end of the year either in Arizona or California. One megawatt powers about 800 homes. The proprietary solar dish technology will then be deployed to develop two of the world’s largest solar generating plants in Southern California with San Diego Gas & Electric in the Imperial Valley and Southern California Edison in the Mojave Desert, in addition to the recently announced project with CPS Energy in West Texas. The projects are expected to produce 1,000 MW by the end of 2012.

Last year one of the original SunCatchers set a new solar-to-grid system conversion efficiency record by achieving a 31.25 percent net efficiency rate, toppling the old 1984 record of 29.4.

Sandia National Laboratories. “Solar Power: New SunCatcher Power System Ready For Commercial Production In 2010.” ScienceDaily

Transparent solar cells offer a multitude of uses. (Credit: Image courtesy of Fraunhofer-Gesellschaft)

To translate the vision of see-through solar cells and transparent electronics into reality, two different transparent coatings would be required – one to conduct the electricity via electrons, the n-conductors, and one in which electron holes enable the electricity to flow, the p-conductors. To produce these coatings the engineers dope the base material with a few other atoms. Depending on which atoms they use, they obtain the differently conducting coatings. N-conducting transparent materials are state of the art, but the p-conductors are problematic. Their conductivity is too low and often their transparency is poor. Manufacturers need a transparent base material which is amenable to both n- and p-doping.

At present, indium tin oxide is mainly used for the n-conductors, but this is costly. Indium has become a rare commodity and its price has increased tenfold since 2002. The search for substitute materials is therefore in full swing. At the same time, various questions need to be answered, such as which materials would be best suitable, what they should be doped with to obtain good conductivity, and how good their transparency is. Research scientists at the Fraunhofer Institute for Mechanics of Materials IWM working in cooperation with other Fraunhofer colleagues have developed material physics models and methods which help in the search.

“If transparent p-conductors with adequate conductivity could be produced, it would be possible to realize completely transparent electronics,” says Dr. Wolfgang Körner, research scientist at the IWM. Using electron microscope images, the researchers initially determine the grain boundaries which most frequently occur in the material – i.e. irregularities in the ordered crystal structure. These defect structures are modeled atom by atom. Special simulation methods calculate how the electrons are distributed in the structures and thus in the solid body. From the data the researchers extract how conductive and transparent the material is. “We have found, for example, that phosphorus is suitable for p-doping zinc oxide, but that nitrogen is more promising,” says Körner.

Fraunhofer-Gesellschaft. “Transparent Solar Cells Made For Windows.” ScienceDaily