Solar Equipment Innovations: Page 4 of 5

Intermediate

Inside this Article

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

Charge Controller Innovations

Modern modules come in a wide range of voltages that rarely match nominal battery bank voltages, so higher-voltage charge controllers make designing battery-based systems much simpler. These MPPT controllers include a voltage-step down capability to convert higher array voltage into lower battery-bank voltage. The controller input is at a higher voltage and lower current; the output is at a lower voltage with a higher current. For example, a 240 W module may have a maximum power voltage of 30 V and a maximum power current of 8 amps. With the module operating at maximum power and charging a 12 V nominal battery, a step-down charge controller would output around 17.5 A to a battery at 13.5 V.

Schneider Electric—and, expected in late 2013, Morningstar—makes controllers to handle PV arrays up to 600 V maximum. One of Schneider’s Conext MPPT controllers can handle a 2,560 W array connected to a 24 V battery bank, or a 4,800 W array at 48 V. (The output is current-limited, so a higher-voltage battery bank allows more array watts to pass through the controller.) MidNite Solar offers controllers that can handle maximum voltages of 150, 200, or up to 250 volts from the array, depending on the model. OutBack Power’s Flexmax charge controllers can be connected to a 150 V array, and are available in 60- or 80-amp models. Morningstar also offers the TriStar MPPT controller that can output 45 or 60 A and accommodate arrays up to 150 V.

Rack Innovations

Auto-Grounding

Racks may be the fastest-evolving section of the PV industry, as there is lots of room for innovation. One of the biggest rack innovations is making it easier to ground the metal module frames to the equipment-grounding conductor or rail. Manufacturers including PanelClaw, S-5!, Schletter, Zep Solar, and others have had their racks tested to Underwriters Laboratories (UL) standard 2703, which includes testing the integrity, continuity, and longevity of metal parts bonded during the construction process, and allows them to offer clips and/or bolts to integrate grounding. This means that modules are bonded to the metal rack as part of the mechanical installation and do not need any other grounding device. Other manufacturers like Daetwyler and Zilla are using mounting hardware listed to UL standard 467 for grounding to accomplish the same result (see “Code Corner: Grounding & Bonding PV Systems” in HP153.)

Railless Mounting

Several rack manufacturers offer pitched-roof mounts designed to reduce installation time by eliminating the traditional module support rails. Proprietary designs by Westinghouse Solar, Silicon Energy’s Cascade Series, Zilla, DynoRaxx, and Zep Solar-compatible modules enable module connection directly to mounting feet. PMC Industries’ AceClamp Solar Kit and the S-5-PV Kit offer module clamps for standing-seam metal roofs that attach directly to the roof.

Innovations for Safer Systems

Dealing with DC Arc-Faults

Section 690.11 of the 2011 NEC added a requirement for direct current arc-fault circuit protection from faults resulting from the failure in continuity of a wire, connection, or other piece of equipment in a system. This can occur when there is a loose connection—for example, when modules’ touch-safe connectors are not properly latched together, or when a DC conductor is connected under a screw that is not properly torqued. These high-resistance connections can cause an arc-fault, resulting in temperatures greater than 5,000°F. Arc-faults can quickly burn through conductor insulation, plastic connectors, module back sheets, and even metal conduit and electrical boxes. They can also lead to ground-faults. For example, when a current-carrying conductor behind a module burns through, one energized end may fall onto the metal rack, allowing fault current to flow through the grounded metal until detected by the ground-fault protection device.

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