Solar Equipment Innovations: Page 2 of 5

Intermediate

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Larger PV module can mean less installation time and expense
While a little more difficult to handle because of its physical size, a larger PV module can mean less installation time and expense.
Glass-on-glass modules
Some glass-on-glass modules allow light to pass through or between cells, creating a pleasant ambience beneath and the possibility of collecting more light reflecting up from below.
Glass-on-glass module from Trina Solar
This glass-on-glass module from Trina Solar offers a Class A fire rating.
SolarWorld’s Sunmodule Protect glass-on-glass module
SolarWorld’s Sunmodule Protect glass-on-glass module offers improved reliability (it’s less prone to water intrusion and cell breakage) and a 30-year linear performance guarantee.
Enphase Energy Microinverter
Microinverters offer module-level multiple power point tracking, monitoring, and simplified array design.
Power-One's Aurora Microinverter
Microinverters offer module-level multiple power point tracking, monitoring, and simplified array design.
AC modules
AC modules have microinverters pre-attached, providing the same benefits as microinverter installations, but reducing installation time and complexity.
Transformerless inverter
Transformerless inverters offer more safety features, as well as higher efficiency and lower weight.
SMA America’s Sunny Boy TL series
SMA America’s Sunny Boy TL series with Secure Power Supply is the first grid-tied inverter that can provide limited PV-direct power during a grid outage—without battery backup.
High-voltage charge controller
High-voltage charge controllers enable the use of smaller-diameter wire from the array to the controller, and the ability to use a wider range of higher-voltage modules in the system.
Railless mounting
Railless mounting decreases the time, materials, and cost of mounting PV arrays,
Auto-ground solutions
Auto-ground solutions - like the dimpled disk which scratches through the anodization on the aluminum module frame to electrically bond it to the adjacent module via the disk - decreases the time, materials, and cost of mounting PV arrays.
Fronius IG Plus inverter
Some inverters, such as this Fronius IG Plus, now provide arc-fault protection, as required by the 2011 NEC.
Screening underneath an array provides an additional measure of system protection.
Screening or mesh that keeps critters out from underneath an array provides an additional measure of system protection.
Wire management solutions
Proper wire management is key to professional-looking installations, and helps ensure that wiring stays safe and secure.
Wire management solutions
Proper wire management is key to professional-looking installations, and helps ensure that wiring stays safe and secure.
Larger PV module can mean less installation time and expense
Glass-on-glass modules
Glass-on-glass module from Trina Solar
SolarWorld’s Sunmodule Protect glass-on-glass module
Enphase Energy Microinverter
Power-One's Aurora Microinverter
AC modules
Transformerless inverter
SMA America’s Sunny Boy TL series
High-voltage charge controller
Railless mounting
Auto-ground solutions
Fronius IG Plus inverter
Screening underneath an array provides an additional measure of system protection.
Wire management solutions
Wire management solutions

Frameless & Glass-on-Glass Modules

The 2012 International Building Code, while still not yet widely adopted in the United States, requires that rooftop rack-mounted PV systems have the same fire classification as required of the roof assembly—Class A, B, or C depending on the building type and location. Class A roofing materials or assemblies have a greater ability to resist fire spreading and to resist burning embers. While residential roofs have not generally been required to be Class A, some areas with high fire hazards are moving in that direction for new construction or significant reroofing projects. For example, Colorado Springs, Colorado, and many cities in California have local agency ordinance requirements for residential Class A roofs. Some roofing materials are considered Class A, like slate, clay, concrete roof tiles, and steel, although they must be installed correctly (for example, eliminating gaps between the roof covering and decking where birds could build nests) to earn this rating. Class A fiberglass-reinforced asphalt composition shingles are also available, while other types of asphalt or wood shingles will typically have a lower Class B or C rating.

Most glass-front, plastic-backed modules have a Class C fire rating, but modules with glass on both sides may meet higher Class A rating requirements. Trina’s TSM PDG5 and Silicon Energy’s Cascade Series are both fire Class A-certified, glass-front and glass-backed modules.

Besides their improved fire resistance rating, some glass-on-glass modules have the benefit of allowing dappled light to pass through for structurally integrated arrays like patio or walkway covers. Looking up at the back of a module that is letting light into an atrium and seeing the PV cells instead of an opaque plastic backsheet is considered by many people an aesthetic improvement and architecturally interesting.  Another advantage of glass-on-glass modules is superior protection for the back of the module as compared to plastic, and enhanced resistance to sheer stresses.

Frameless versions of glass-on-glass modules are available (including many thin-film modules) that have no metal frames to ground, so the labor and material costs of grounding module frames to racking are eliminated. (Note that the rails still have to be grounded.)

AC Modules & Microinverters

The benefits of AC module and microinverter systems include simplified array design with no string sizing necessary and MPPT for every module, rather than a whole array or string. Unlike with a string inverter, one module or inverter failure does not affect the whole system. In addition, module-level data monitoring capabilities allow easy troubleshooting of an underperforming array or module, and arrays are more easily scalable, as modules can be added without dealing with the constraints of series strings.

Both system types are extremely safe to install and operate, compared to systems with string inverters, because DC voltages are kept to a one-module maximum; all equipment connectors are touch-safe; and DC voltages will generally stay below the 50 V limit associated with shock hazards. Shutting off the main service AC disconnect or PV system disconnect also immediately deenergizes all the PV system conductors except module leads, as the inverters shut off immediately without the presence of grid voltage. One of the benefits of AC modules includes even-quicker installation, since the inverter is preinstalled—there is no DC field wiring, and no DC arc-fault protection necessary. (Metal module frames and any other metal equipment like junction boxes or racks still need equipment grounding.)

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