| Solar power and solar panels are getting a lot of | | | | applications, from boats and RV's to electric cars and |
| attention as part of the solution to our energy crisis. | | | | space stations. |
| Solar energy, also called photovoltaic energy, is | | | | The Solar Array |
| undergoing rapid changes thanks to massive | | | | Modules are combined to create solar arrays. An |
| investment in research and development. This article | | | | array is a group of modules assembled together and |
| will discuss the basic makeup of photovoltaics in | | | | designed to meet a certain electrical load. You've |
| hopefully easy-to-understand terms. | | | | probably seen most arrays mounted on the rooftops |
| Solar Cells | | | | of homes. These arrays are designed to generate a |
| A solar panel is made of several photovoltaic cells. | | | | certain amount of electricity over the course of a year. |
| The cells are very thin, about 1/100th of an inch thick | | | | Efficiencies |
| and usually 3 to 4 inches square. These cells convert | | | | Generally solar modules convert about 10-15% of the |
| sunlight to energy by the photovoltaic effect (we will | | | | energy that strikes them into electricity. This means |
| discuss this effect in detail in a later article). These cells | | | | that for every 100 units of energy that actually hit the |
| do not require fuel and have a standard lifetime of | | | | panel, only 15 of them actually enter the home as |
| 20-30 years. | | | | electricity. This is the biggest area of research now, as |
| Solar Panels & Modules | | | | scientists recognize that significant advancements in |
| Photovoltaic (PV) cells are assembled together to | | | | solar efficiency will lead to cheaper solar energy. |
| create a solar module. The module is what you are | | | | AC vs DC |
| used to seeing as a panel. It has anywhere from 2 to | | | | Panels generate direct current (DC) electricity. Think of |
| 200 cells assembled together, encased in tempered | | | | a garden hose that is simply turned on produces water |
| glass and aluminum to make them weather resistant. | | | | in a steady stream. Most household electronics and |
| Tying Them Together | | | | the electrical power grid are designed to take |
| Like batteries, cells can be combined in series or in | | | | alternating current (AC) power. Now imagine that the |
| parallel to create larger and more specific voltages | | | | water of coming out of the garden hose is being |
| and amperages. For instance, four 1-volt/1-amp cells in | | | | turned off and on so quickly that it has a "pulse". This is |
| series will combine for 4 volts, but the amperage will | | | | done because AC power travels over long distances |
| stay at 1 amp. By contrast, four 1-volt/1-amp cells in | | | | much more efficiently. |
| parallel will maintain 1 volt but have 4 amps of output. | | | | This means however, that the electricity coming out of |
| You can multiply the amperage by the wattage (in the | | | | the solar array must be converted to AC if it is going |
| example above 4 x 1) to get the watts generated. A | | | | into your home. This is done with an inverter, which |
| watt is a measure of energy (think of a 40-watt light | | | | takes the DC power and makes AC power. The |
| bulb). | | | | power is then ready to service your home, an |
| Sizes and Shapes | | | | electrical grid, or a device. Some devices (certain lights, |
| Modules can be made in a many sizes and shapes to | | | | batteries, special devices) use DC power and |
| fit their application. Panels come in standard | | | | therefore do not need an inverter. |
| rectangular, triangular, foldable, and even thin-film rolls. | | | | Check out Solar Panels for more information. |
| This means they can be used in a wide variety of | | | | |