Solar Equipment Innovations

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

Along with a growing demand for PV systems comes pressure for lower-cost and higher-efficiency equipment, safer operation, and faster installations. Manufacturers of PV equipment—inverters, modules, racks, and other balance-of-system components—respond with innovative devices, drawing upon feedback from installers and designers.

PV Module Innovations

Changes in PV modules happen in two areas. First, manufacturers make incremental improvements that result in efficiency—and power—gains. Second, major design changes happen, like increases in the size or number of cells in a module, different frames or mounting methods, and different materials used for the front and back protection.

Higher Power

The PV industry experiences a seemingly inevitable march toward more powerful, larger modules: In 2000, 75-watt modules were commonplace; in 2009, 200 W modules were plentiful; in 2012, 250 W modules were becoming the norm. Today, there are more than 1,000 different models of 300 W or greater modules on the market and manufacturers continue to expand the selection in this size range.

Larger modules mean more power installed more quickly—15 years ago, a 3,000-watt array would have meant racking and wiring 40 modules. Today, that can be accomplished with 10 modules. Fewer wired connections mean savings for both the system owner and the manufacturer. For framed modules, the ratio of aluminum frame material to the module footprint decreases with wattage increases, which lowers costs for manufacturers and reduces mount costs.

Most higher-wattage modules, in the range of 300 to 445 W, are designed with 72 (or 96) cells in series, rather than 60 cells, which was the standard for many years. Six-inch-diameter cells have replaced 5-inch cells—a 44% increase in surface area, and more area means more current per module.

Because all those cells are wired in series, higher voltage is produced as well. The open-circuit voltage on 72-cell modules can exceed 45 volts (60 V on 96-cell modules). Higher-voltage modules can limit design options for arrays connected to step-down charge controllers or string inverters. Higher voltages equate to bigger “building blocks” and means fewer choices for PV string sizing. Depending on the equipment’s voltage window, it may be impossible to specify the right number of 72- or 96-cell modules that won’t exceed the equipment’s high-voltage limit on the coldest days, nor drop below its low-voltage window on hot days. This is especially true for climates that experience wide temperature swings.

Higher-wattage modules can sometimes limit the overall array size. For example, if a string inverter has a voltage input window of 300 to 600 VDC, in many locations when temperatures are hot at least 10 of the 72-cell (300-watt) modules need to be in series to keep the inverter humming. This translates to a (minimum) 3,000 W array—with only one string. Furthermore, with average 72-cell module specifications, if the expected low temperature is 14ºF (-10ºC) or less, then the maximum number of modules in series would be 11. This results in a very narrow range of system size options: 3.0, 3.3, 6.0, 6.6 kW, etc.

One solution is to use an inverter with a wider maximum power point tracking (MPPT) window (such as the PowerOne Aurora PVI models, which have a window of 200 to 530 VDC). This could allow as few as six or seven modules in series. AC modules or microinverters (see below) are another option for high-wattage modules.

Higher-wattage modules also have a larger footprint. For example, while 72-cell modules are generally about the same width (about 39 inches) as 60-cell modules in the 180 W to 260 W range (six cells wide), they are 12 cells high instead of 10—about 12 inches taller and 8 pounds heavier. This increases the load on the rack attachment points, with the same amount of rail holding more module weight. Also, more caution is needed when moving larger modules—typically it requires that two people carry each module.

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