Solar shingles

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Solar shingles (or photovoltaic shingles) are a new type of solar energy system that, at first glance, look like regular asphalt shingles but are actually photovoltaic cells (PV). There are several varieties of solar shingles, including shingle-sized solid panels that take the place of a number of conventional shingles in a strip, semi-rigid designs containing several silicon solar cells that are sized more like conventional shingles, and newer systems using various thin film solar cell technologies that match conventional shingles both in size and flexibility. They are manufactured by only a few companies worldwide including SunPower Corporation and Atlantis Energy Systems.

1 History
2 How they work
3 How they look
4 What is in a PV module
5 How they connect to the grid
6 Cost
7 See also
8 References
9 External links

[edit] History

The technology has grown considerably since their inception for use for thermal-solar hot water heaters during the 1920s in Florida and California. Recently there has been a surge toward large-scale production of PV systems. In parts of the world with significantly high insolation levels, PV output and their economics are enhanced. PV (Photovoltaic) modules are the primary component of most small-scale solar-electric power generating facilities. Since the turn of the century, there have been major advancements in solar power and their efficiency; this includes the 2005 release of solar shingles.

[edit] How they work

They act as any normal solar energy system would. They capture sunlight and transform it into energy. Most Solar Shingles are 12 inches wide (when stacked have 5 inches of exposed area) by 86 inches long and can be stapled directly to the roofing cloth. Different models of shingles that are produced have different mounting requirements. For example Uni-Solar's SHR 17 can be applied directly onto roofing felt intermixed with regular asphalt shingles. As opposed to Atlantis Solar Energy's Sunslates^TM which are fastened to the roof by steel storm anchor hooks mounted on 2X2 sleepers, these tiles are fastened together by gas-tight connections that connect with a screwdriver-like tool (provided) which locks and secures them into place.

Roof tiles provide optimal solar cell placement and eliminates shading from upper roof tiles. They also require less roof space and allows for optimal system placement.

[edit] How they look

Solar-shingled roofs have a deep, dark, purplish-blue color, and therefore look similar to other roofs in most situations. They have aesthetics that are positive in some peoples’ opinion. Unlike other upcoming alternative resources for the home, such as wind turbines or home diesel generators (to reduce transmission costs), they are not obviously solar collectors.^[1]

SunPower shingle roof tiles are all-black in design to blend into Flat or S-Tile roofs.

[edit] What is in a PV module

The most common set up are PV shingles with mono or polycrystalline solar cells directly integrated with regular asphalt shingles. The main design of photovoltaic cells, consist of a large-area, single layer p-n junction diode, which is capable of generating usable electrical energy from light sources with the wavelengths of sunlight. These cells are typically made using a silicon wafer. First generation photovoltaic cells (also known as silicon wafer-based solar cells) are the dominant technology in the commercial production of solar cells, accounting for more than 86% of the solar cell market. The typical power output spans several watts (roof shingles) to about 50 watts (roof tiles with crystalline solar cells).

For more information on theory and energy processing, see Solar cell.

[edit] How they connect to the grid

PV systems connected to the grid can be broken up into two categories. Those that have battery backup and those that do not. PV systems that lack a battery backup are integrally connected with utility power. The system's power output goes straight into the grid; as a result, this type of system usually saves the owner the most money on electric bills. The other type of PV systems are those that are equipped with battery backups. In these systems, excess power is used to charge up backup batteries which can provide up to 8 hours of power in the event of a power outage.

As would be expected, these systems require different hardware in order to serve different functions. Non-battery backup units require an inverter which converts the direct current output from the shingles into alternating current that most household appliances use. A meter would also be beneficial to allow one to track the system's performance. On the other hand, battery backup units require an array of additional hardware. This includes batteries, battery enclosures, battery charge controllers, and separate sub panels for critical load circuits.

[edit] Cost

Solar shingles are more expensive to install than typical PV panels, but the extra cost is sometimes considered a small price to pay for the aesthetic benefits. Also, the solar shingles offset the cost of traditional shingles for that section of the roof.^[2]

Large homebuilders in California like Lennar are partnering with SunPower to offer new construction solar homes that have solar systems installed prior to moving in. Reducing the overhead and using solar roof tile technology makes solar a standard option like granite countertops, making solar an affordable solution to reduce electricity costs.^[3]