AC vs. DC Electric: Why should you care?
Thomas Edison, one of the most energetic and prolific inventors of all time, patented an electric distribution system in 1880 that was necessary to capitalize on the invention of the electric lamp. He called it the Edison Electric Illuminating Company. You know it today as General Electric. This new power was generated as direct current, otherwise known as DC. It worked great for lights and motors, but had one small drawback. Direct current could only transmit a limited distance and it required generating stations every mile or so.
In the early 1890's, a rival company offered a different mode of electricity. Pioneered by George Westinghouse and Nikola Tesla, alternating current, or AC, was a breakthrough technology that enabled power to be transmitted hundreds of miles between generating plants. In the "War of the Currents" era, there was tremendous competition between the two as to what system the country would go with. Edison and Westinghouse both submitted bids to wire the Chicago World's Fair. Westinghouse won and the rest is history.
It turns out, however, that direct current was pretty good stuff and it's still utilized by trains, planes, automobiles, ships, phones, and computers - virtually everything other than homes and buildings. Why? It so happens that DC is much more efficient, reliable and easier to control than AC. For example, a one horsepower AC motor draws 8 amps, while a one horsepower DC motor draws only 4 amps. Consequently, a DC motor is almost twice as efficient and uses half the electricity of an AC motor.
Why am I so charged up over the competing powers? Think about solar panels. All solar panels produce direct current and there's no reason to worry about the ability to transmit long distances since the panels are located on your roof or in your yard. If you have a swimming pool, the pump is usually the second most expensive electrical load in your home (after air conditioning) and it really doesn't care if it runs day or night. Pool pumps are now available in DC, which is a great way to lower your power bill. By utilizing the pump during daylight hours, it can run off solar panels whenever the sun shines. Bear in mind that pressure and submersible pumps are readily available in DC, as well as refrigerators, freezers and air conditioners. DC air conditioners seem to be better suited for large open spaces, though. A good way to utilize these is to install them independently of your normal household air conditioning and let them work during the day to help defray energy costs.
By utilizing DC power in your home, with DC motors, you can reduce the number of solar panels needed to power your house and if you choose to couple your panels with a battery, you may be able to run DC electrical items day and night to power lights and other household items without incurring charges from a power company. As a matter of fact, you might have surplus power to sell back to them.
Isn't it interesting how history has a way of repeating itself? Perhaps, Thomas Edison knew more about energy efficiency than generally thought. It's a testament to him that the entire New York City Subway system, to this day, is run by DC.
Whether you want to save money, save the earth, or rid our dependence on foreign oil, there are now steps you can take to be energy independent.
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© 2008 Jean Morrissette