| Sun-powered electric options were once limited to | | | | Crystalline modules lose efficiency at higher |
| large dark panels, but now consumers have a | | | | temperatures. Solar film units are less sensitive to |
| choice. In addition to panels of single or | | | | environmental temperature, losing perhaps 2% of |
| multi-crystal solar cells, solar film or thin film solar | | | | their power at 100F, compared to 6% power loss |
| units are available in frames or in building materials | | | | for a traditional crystalline system. The cell |
| such as roof laminates. Each technology has | | | | temperature can be modified by allowing for air |
| advantages. The choice depends on budget, | | | | flow around the system, but if ambient |
| space, climate, and aesthetics. | | | | temperatures tend to be high, a thin-film system |
| The cells that make up a crystalline photovoltaic | | | | may be the right choice. |
| module stand out as dark rectangles or octagons. | | | | New amorphous silicon modules produce 20% to |
| A multi-crystalline cell often appears as a sparkly | | | | 25% more energy production than rated. While |
| rectangle. The electrical connections in both | | | | this will stabilize to the normal rated output within |
| technologies show as a pattern of silver lines. | | | | six to twelve months, any system using these |
| "Thin-film" does not refer to a specific material. | | | | modules must be able to handle the initial higher |
| These modules can be made of amorphous silicon | | | | output. Traditional modules stabilize immediately, |
| (a-Si), copper indium gallium diselenide (CIGS), and | | | | which eliminates this consideration. Once the a-Si |
| cadmium telluride (CdTe). Amorphous silicon is | | | | modules become stable, they will degrade at |
| popular for applications where looks matter. Since | | | | approximately the same rate as other systems. |
| it can be put on plastic, as well as on glass, a-Si | | | | Not all climates are sunny, so shade and low-light |
| can be produce in flexible continuous rolls. | | | | performance may be an additional concern. |
| Amorphous silicon is used in laminates, solar | | | | Flexible sun-powered panel cells can be the same |
| shingles and roofing tiles. | | | | length as the module they are on. These cells are |
| Aside from appearance and versatility, efficiency | | | | less likely to be completely in shade than |
| is a factor in PV material selection. A convention | | | | crystalline cells, which are usually just five or six |
| framed crystalline system will produce more | | | | inches across. |
| power in less space. The flexible photovoltaic | | | | One type of technology that gives good |
| systems, while more aesthetically pleasing, are | | | | performance in shade or conditions of low light is |
| about half as efficient. This means a flexible | | | | that used by Uni-Solar products. These modules |
| module will need twice as much space to | | | | are flexible, and have triple junction cells made of |
| generate the same amount of energy as a | | | | amorphous silicon. This technology allows bypass |
| conventional system. | | | | diodes to be used within the module, so that any |
| This has a big effect on system size. A three by | | | | cell that is in shade can be bypassed. In addition, |
| three foot solar laminate system can deliver 60 | | | | this arrangement lets each element in the |
| to 70 W, with efficiencies as high as 8%. A three | | | | multi-junction cell capture a different wavelength |
| by five foot crystalline module can provide 170 to | | | | of light. This gives better energy production in |
| 220 W, with up to 17% efficiency. But power | | | | conditions where lighting is indirect or not uniform. |
| density is not the only consideration. | | | | For more information on Solar Film, check out our |
| Cell temperature has an impact on PV cell power. | | | | website. |