Alternative Energy Glossary – Solar Energy Information

Photovoltaics (PV): the field of technology and research related to the application of solar cells to supply energy by converting sunlight directly into electricity.

Photovoltaic module: or photovoltaic panel or solar panel is a packaged interconnected assembly of photovoltaic cells, also known as solar cells.

String: A number of modules or panels interconnected electrically in series to produce the operating voltage required to start the inverter typically consisting of 9 to 12 modules. (most situations, 9 modules is a minimum to start the inverter.)

Array: The total module layout at a given entry point or meter consisting of 1 or more strings.

Balance: An array having modules with same output and strings with same number of modules

Inverter: a type of electrical device that is made to change the direct current (DC) electricity from a photovoltaic array into alternating current (AC) for use with home appliances and possibly a utility grid.

Switchgear: (electrical panel, main panel, subpanel) used in association with the electric power system, or grid, refers to the combination of electrical disconnects, fuses and/or circuit breakers used to isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream.

DC Disconnect: a switch placed between the array and the inverter to shut off the input of DC power to the inverter.

AC Disconnect: a switch placed between the inverter and the switch gear to shut off the input of AC power to the building and power grid

Monocrystalline: Silicon that is pulled as a single crystal.

Polycrystalline: silicon is a material consisting of multiple small silicon crystals.
(Both forms of Silicon crystal are used in the manufacture of photovoltaic cells. Monocrystalline has a higher efficiency rating and is also more costly to produce. The majority of panels being purchased today are polycrystalline)

Thin film: A Thin-Film Photovoltaic Cell (TFPV) is a solar cells that is made by depositing one or more thin layers (thin film) of photovoltaic material on a substrate. Thickness ranges from a few nanometers to tens of micrometers. Thin Film Solar Cells are made up of what is generically referred to as Thin-film silicon or TF-Si. They are more specifically categorized according to the photovoltaic material used:

Cadmium Telluride (CdTe)
Copper indium gallium selenide (CIS or CIGS)
Dye-sensitized solar cell (DSC)
Organic solar cell

The TFPV types that appear in bold letters are currently in mass production while the rest are still in the development or pilot-plant phase.

Thin film technologies are also being developed as a means of substantially reducing the cost of photovoltaic (PV) systems. They are cheaper to manufacture owing to their reduced;

material costs
energy costs
handling costs
capital costs

However, Thin film produces less wattage in a given area. Thus, it takes more area or modules to produce the same output as crystalline modules.

Thin film is produce in a flexible form for direct film applications on metal roofs, railings on commercial building or any surface with curved or non-flat surface. It is also available in a glass encasement for standard rack mount installations