PV Modules Flashcards
The most common PV module technology on residential and commercial projects is __________.
crystalline silicon
Thin-film modules are much less common than crystalline silicon modules on residential and commercial projects. Monocrystalline and polycrystalline are both types of crystalline silicon modules and are both commonly used.
The module type that dominates the market is __________.
crystalline silicon
True or False: Polycrystalline wafers are cut from cylindrical ingots that have been squared off, leaving the corners of these cells rounded.
false
The corners of a monocrystalline cell are rounded because the cells are cut from ingots that are __________.
cylindrical
Monocrystalline cells are cut from a cylindrical ingot, and the rounded corners are the extents of the cylinder before the ingot is squared off.
Match the following descriptions to monocrystalline, polycrystalline, or thin-film modules: Made from a square ingot
polycrystalline
Match the following descriptions to monocrystalline, polycrystalline, or thin-film modules: Made from a cylindrical ingot
monocrystalline
Match the following descriptions to monocrystalline, polycrystalline, or thin-film modules: Can be installed on a flexible substrate
thin-film
Match the following descriptions to monocrystalline, polycrystalline, or thin-film modules: Square-cut cells fit better inside rectangular module forms
polycrystalline
Match the following descriptions to monocrystalline, polycrystalline, or thin-film modules: Back sheet is more visible due to shape of cut cells
monocrystalline
Match the following descriptions to monocrystalline, polycrystalline, or thin-film modules: Costs typically are higher
monocrystalline
Match the following descriptions to monocrystalline, polycrystalline, or thin-film modules: High quality cells are marginally more efficient
monocrystalline
Match the following descriptions to monocrystalline, polycrystalline, or thin-film modules: Uncommon on residential projects
thin-film
True or False: Quality, availability, and cost typically drive the decision between monocrystalline and polycrystalline modules.
true
Polycrystalline and monocrystalline modules are both very widely used on PV projects. While polycrystalline modules tend to cost slightly less, and be marginally less efficient than monocrystalline modules, the cell technology itself is not typically the deciding factor. Rather, cost, availability, and quality are the typical considerations that outweigh others when deciding which modules to use
A junction box can be __________.
full-size or split
Some modules have single, full-size junction boxes, which contain bypass diodes and serve as a point of transition between internal circuit components and external circuit connections via module leads. Many newer modules have three junction boxes - “split” junction boxes - with each box containing one diode, and two of the boxes acting as transition points between the internal circuitry and the module leads. In the case of split junction boxes, one is positive and one is negative.
A junction box serves as a transition point from internal to external wiring and contains __________.
bypass diodes
Internal PV cell circuit wiring is connected to the external module leads (external wires that are used to connect a PV module to other modules or circuits) inside the junction box. The junction box also includes bypass diodes, which operate when shading falls on a module to allow the current to bypass the shading and avoid hot spots
One important safety feature that is part of a PV module and helps to eliminate hot spots and reduce fire hazards is a __________.
bypass diode
Bypass diodes are installed in PV module junction boxes and operate when a module experiences shading. Shade will essentially “block” current flow and cause a high-resistance point on the circuit, which becomes a “hot spot”. Bypass diodes allow the current to bypass those shaded areas and continue to flow, mitigating hot spots
When shading occurs on a PV module, the current flow is essentially blocked by the shade, which can cause a high-resistance hot spot. These hot spots are mitigated by the presence of __________.
bypass diodes
Bypass diodes are installed in a module junction box and will operate when a module experiences shading. Shade will essentially “block” current flow and cause a high-resistance point on the circuit, which becomes a “hot spot”. Bypass diodes allow the current to bypass those shaded areas and continue to flow, mitigating hot spots
Module quick connectors must be installed exactly per the manufacturer’s instructions, and they must be __________.
the same make and model
Connectors on module leads must be the same make and model or be listed / rated by both manufacturers to be able to work together (known as “intermatability”). Some connector types are listed by their manufacturer to be compatible with other brands, but those other brands may not reciprocate that compatibility listing so it’s important to verify compatibility listings for both types. It is extremely rare to find both, so the best option is to use the same make and model for all mated connectors
True or False: It is acceptable to use a connector on a source circuit “homerun” wire that is different from the connector on the PV module leads if they plug together securely.
false
Connectors on module leads must be the same make and model or be listed / rated by both manufacturers to be able to work together (known as “intermatability”). Some connector types are listed by their manufacturer to be compatible with other brands, but those other brands may not reciprocate that compatibility listing so it’s important to verify compatibility listings for both types. It is extremely rare to find both, so the best option is to use the same make and model for all mated connectors.
The number of cells in a PV module dictates the module __________.
voltage
Cells are connected in series within the module laminate. Cells are typically ≈0.5 volts each, so the number of cells in series will determine the voltage of the module (since voltage is additive in series connections)
A PV module’s voltage is determined by the __________.
number of cells
Cells are connected in series within the module laminate. Cells are typically ≈0.5 volts each, so the number of cells in series will determine the voltage of the module (since voltage is additive in series connections)
A half-cut cell module is configured into two halves, which gives them __________.
better shade response than full-cell modules
A half-cut cell module is internally configured in a way that if part of one half of the module is shaded (with the dividing line being at the center of the long edge, with a top half and a bottom half), the unshaded portions of that half will continue to produce (similar to how a full-cell module would) due to the presence of bypass diodes. The other half of the module will also continue to produce, which would not be possible in a typical full-cut cell module; therefore, power output will be greater than a full-cell module in the same shading scenario
True or false: A full-cell module has better shade response than a half-cut cell module due to the presence of bypass diodes.
false
A half-cut cell module is internally configured in a way that if part of one half of the module is shaded (with the dividing line being at the center of the long edge, with a top half and a bottom half), the unshaded portions of that half will continue to produce (similar to how a full-cell module would) due to the presence of bypass diodes. The other half of the module will also continue to produce, which would not be possible in a typical full-cut cell module; therefore, power output will be greater than a full-cell module in the same shading scenario
Calculate the efficiency of a half-cut PV module that is 2261 mm x 1134 mm and rated at 535 watts.
=20.9%
- Determine area of module in square meters
2.261 m x 1.134 m = 2.56 m² - Divide module wattage rating by module area
535 W ÷ 2.56 m² = 209 W/m² - Divide module rated W/m² by STC W/m²
209 W/m² ÷ 1000 W/m² = 0.209 x 100 = 20.9%
True or false: The larger a PV module’s size, the higher the efficiency will be.
false
Efficiency is a ratio of power-in (sunlight) to power-out (electricity produced by the cell or module) and it depends on several factors including manufacturing procedures. Modules of a given size are manufactured and tested in the factory, then placed into “bins” based on their tested wattage output and classified by that wattage rating. Inconsistencies in the manufacturing process lead to variations in wattage ratings, and the efficiency depends on the size of the module in relation to its wattage rating. Efficiency ratings provided by module manufacturers are based on standard test conditions, and efficiencies will vary based on actual irradiance levels
True or false: A PV module’s rated efficiency depends on its physical size and STC rated power output compared to STC irradiance.
true
Efficiency is a ratio of power-in (sunlight) to power-out (electricity produced by the cell or module). Modules of a given size are manufactured and tested at standard test conditions at the factory, then placed into “bins” based on their tested wattage result and classified by that wattage rating. A module’s rated efficiency is based on the actual tested watt rating at the factory compared to STC irradiance value of 1000W/m²
