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Wednesday, January 23, 2013

Go Green With The Latest Electrical Trends


Chances are that you have heard a lot about "going green" in all kinds of industry and business contexts. When it comes to finding the right electrical products for your company or property, going green means reducing your energy consumption and carbon footprint while safely disposing of hazardous waste materials that your used electrical products may contain.
Harnessing the following electrical trends will help you effectively manage your energy consumption levels and reduce the environmental impact of your business or residential property:
  1. Daylight Harvesting
    Using photo-sensors and a set of integrated controls, daylight harvesting systems reduce the use of artificial indoor lighting when natural daylight is available in order to reduce energy consumption. Daylight harvesting systems are designed to maintain a minimum recommended light level and can be customized according to the unique needs and uses of each individual space.
  2. Occupancy and Vacancy Sensors
    With strategically installed sensors, these "smart" motion detection systems adjust light levels from room to room based on occupancy, ensuring that you use only the electricity you need. Once a room is vacated, these sensors automatically manage the operation of lights to help minimize use.
  3. Fluorescent Lighting
    Fluorescent lighting has become an increasingly energy efficient solution over the years by utilizing smaller diameter tubes which consume less electricity. With double the average rated life of their predecessors, they also save companies significantly on maintenance costs. The required electronic ballast systems required for T8 and T5 bulbs further reduces the energy consumption of these lamps.
  4. LED Lighting
    LED lighting offers significant improvements in energy consumption and product lifespan when compared to incandescent lamps of similar size and output. Unlike fluorescent options, LEDs contain no mercury, which saves your company on disposal costs and helps to reduce environmental impact.
  5. Photoluminescent Signage
    Glow-in-the-dark design elements use zero energy and thus incur no operational or maintenance costs. There are currently a variety of low-cost photoluminescent indoor signage options available, such as "Exit" and "Fire Extinguisher" signs.
  6. VFDs (Variable Frequency Drives)
    Sometimes referred to as AFDs (Adjustable Frequency Drives), these units are commonly used in large-scale ventilation systems and in conjunction with heavy machinery (pumps, elevators, conveyor belts, etc.) to save energy by effectively matching system output to demand.
  7. Power Factor Correction
    The power factor of an AC electric system is defined as the ratio of the real power flow to the apparent power contained in the circuit. An automatic power factor correction unit significantly improves this power factor, resulting in greater overall system efficiency.
  8. Energy-Efficient Electrical Transformers
    In 1992, the Environmental Protection Agency determined that 61 billion kWH of electricity was being wasted each year in transformer losses. In the two decades since this discovery, thanks in no small part to revised industry regulations, dramatic advances in transformer technology have corrected this waste, resulting in 97.7% to 99% efficiency standards. Replacing old, outdated commercial and industrial transformers can reduce your company's energy costs significantly and help save the environment.
  9. Hazardous Waste Disposal
    It is important to consider the environmental impact of your choices when designing green lighting systems. Fluorescent bulbs contain mercury and the accompanying ballast systems may contain PCBs. Due to the presence of these hazardous substances, disposal of used bulbs and ballasts requires special methods and techniques. By switching to LEDs, you can save your company on disposal costs and reduce your environmental impact.

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Sunday, January 6, 2013

Corona Effect on Transmission lines




Corona Effect:
The phenomenon of violet glow, hissing noise and production of ozone gas in an overhead transmission line.

 Reason :
Due to cosmic rays, ultraviolet radiations some ionization is always present in the air. Under normal condition air around the transmission cable contains ionized particles i.e. free electrons, positive ions and also neutral molecules. When the line becomes live means when potential difference applied between the lines, potential gradient is set up in the air and have maximum value at the conductor surfaces. Because of this potential gradient the free electrons acquire greater velocity. With the increase of the line voltage the potential gradient increases and the velocity of the free electrons increase also. When the potential gradient of the conductor surface crosses the maximum limit then the free electrons get enough kinetic energy to strike a neutral molecule and make some more electrons free from that molecule. One electron free then creates one positive ion and some free electrons. Usually 30KV per cm treated as the limit of potential gradient. Those free electrons strike more neutral molecules and keep this process going all like nuclear fission. So this process of ionization is cumulative. The result of this ionization is that either corona is formed or spark takes place between the conductors.

 Factors affecting corona are
a) Atmosphere: During stormy or rainy weather corona occurs at much less voltage as compared with fair weather. Because during those cases ion density around the conductors is much more than that of fair weather.
b) Conductor Size: The unevenness of the surface of the conductors decreases the breakdown voltage. Because of this reason with low voltage the insulation will breakdown and create sparks and corona. That’s why solid conductors are used mostly instead of stranded conductors to reduce the corona.
c) Spacing between conductors: Larger the gap between the conductors lesser the corona.
d) Line voltage: Every line voltage has a limit. After that limit breakdown will occur and will create corona and spark. So with the application of small line voltage possibility of occurring corona is lesser.

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Friday, January 4, 2013

Eggshells for Energy Storage

                            Researchers hope to improve super capacitors using chicken-egg shells

7 December 2012—Owners of electric cars may soon be driving on eggshells, ifDavid Mitlin has anything to say about it.
Mitlin, a professor of chemical and materials engineering at the University of Alberta, in Edmonton, Canada, is working on a way to turn waste eggshell membranes and egg whites into materials for high-performance supercapacitors. Supercapacitors offer high power density, charging and discharging far faster than rechargeable batteries. Unfortunately, they store much less energy. Mitlin thinks the membranes inside eggshells could help crack that problem.
“If you could keep the very nice power of a supercap but extend the energy density even to be that of a mediocre lithium-ion battery, you’d really enable the applications world in the automotive sector and in consumer products,” Mitlin told attendees at the Materials Research Society’s Fall Meeting in Boston last week.
Supercapacitors are electrochemical devices that store a double layer of charge on activated carbon as electrodes. Mitlin and postdoctoral fellow Zhi Li propose replacing the activated carbon with eggshell membranes from certain industrial chicken farms. These farms provide eggs yolks for the production of medicine and cosmetics but discard the shells.
Mitlin and Li start by heating the shells to 800 °C. They then activate the material by heating it to 300 °C in air for two hours. “You take the membranes and transform them into this almost construction-paper-looking thing,” says Mitlin. The carbonized membranes retain their porous structure, providing plenty of surface area on which to hold an electrical charge. And their relatively high nitrogen content—about 8 percent after processing—leads to capacitance that isn’t just chicken feed, though scientists are unsure why this happens. Mitlin measured a capacitance of approximately 300 farads per gram in the eggshell supercapacitors, about 100 times as much as those that used activated carbon. The material retained 97 percent of its efficiency even after 10 000 charge-discharge cycles in an acidic electrolyte.
But Mitlin didn’t just stop at the shell. He also used carbon from the egg whites to create a porous material that he used as the anode in a lithium-ion battery. He wouldn’t go into detail about the production process, but he says the anodes showed a capacity of 1800 milliamp hours per gram. “As far as we know, it’s the highest ever reported reversible capacity for carbon,” he says.
Mitlin and his colleagues are founding a start-up company, to be named Altacap, to look into commercializing the technology. “We’re trying to figure out the target market to go after,” he says. “The obvious one is automotive.” The power density of supercapacitors could significantly shorten the time for recharging electric vehicles, which now takes several hours.
One challenge of competing commercially is that activated carbon is already very cheap. But Mitlin says the egg-based approach could compete on performance. For example, the carbonized shells work well with a water-based electrolyte, allowing the replacement of the usual polymer electrolytes, which can be more costly and potentially toxic.
The membrane material also meets one of the goals of Canada’s clean-energy initiative, which seeks to use biowaste to produce energy. He says that industry produces hundreds of tons of eggshells, and the supply of egg whites is virtually unlimited. Because the pharmaceutical industry generally uses the yolks, he hasn’t explored potential uses for that part of the egg. But if the shells and the whites turn out to be as useful as he hopes, Mitlin’s technology could be a real chicken coup.


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