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| PV is an abbreviation for photovoltaics. Photo means light, and Voltaic refers to voltage or electrical energy. The photovoltaic effect was discovered over 150 years ago by a French scientist named Edmund Becquerel in 1839. | |
| Today's solar cells use silicon as their base material, and then special coatings are applied to turn thin wafers of purified silicon into a solar battery of sorts. This modern PV cell was discovered by accident in 1954 when Bell Telephone Labs was experimenting with silicon for uses like computer chips. Since that day PV has been getting more efficient and cheaper for consumers. | |
| Did you know? Silicon is the most abundant element on the earth, being present in dirt, rocks and sand. The silicon from 1 ton of sand made into PV cells would make as much energy as 500,000 tons of coal! All that and it doesn't have to be mined! |
| Take a look at your calculator. I'd just about bet that your calculator or your friends' calculator has a little PV window on it. It seems that about 1/2 of all calculators these days have PV power on them. There are PV powered devices all around us: watches, clocks, lights at bus stops, mountaintop radio & TV transmission stations, roadside emergency call boxes, satellites in space and even this web site! Yes, this web site is 100% powered through PV. |
| Well, PV has been used for home installations since the 1970's. It was expensive then, but some people still got their hands on it and managed to set it up. Today is a different story though. There are estimates of over 120,000 homes using PV in the USA, and many times that number elsewhere. Some experts have estimated that well over 1 million homes in Europe alone are powered with PV. | |
| You can't run your central air conditioner all day long, use that electric stove or electric water heater very cost effectively with a PV system. (You can do it, but the key phrase is "cost effective"!) There are people that do use PV & wind power (wind is a solar energy by-product) to run very high power consumption devices. I've seen articles and heard stories of people running heliarc welders and hydrogen gas production facilities on PV based systems. |
| Our PV array currently is made up of 16 - 90watt modules and 4 - 50watt modules. Normally, that would give me a standard rating of 1640 watts. It would be great if the system really produced 1640 usable watts, but battery & charging are only about 90% efficient at best, inverters only reach about 90-95% total efficiency, and these figures are based on having the panels angled directly at the sun, but we have them sitting at an angle of about 5 degrees south fixed slope on the top of the garage, further reducing the wattage depending on the time of the year. The system probably puts out 1100 usable watts in the summer, and 500 usable watts or less during the winter. This may all sound complicated, but actually it works very simply. Multiply this figure by about 5 hours of prime sunlight (barring any clouds) and you have the approximate maximum output this array will produce on any given day. Currently we are only using 1 charge conroller for about 60% of the system, and the other panels are connected directly to the batteries. (Of course using breakers for safety!) |
| Well, the next stop for the energy is the charge controller, but before it get's there it must pass through the electrical safety devices, commonly known as breakers. |