Cell:
The basic unit of a PV system is the cell. First a silicon crystal is
grown into a bar shape called an ingot. This is then cut into thin slices
and electrodes are attached to create the cells. Module:
A module is a package in which a set of cells are arranged in rows and
covered with sturdy glass so that they can be mounted on a roof. Array:
An array consists of multiple modules (panels) arranged either in series
or in parallel and mounted on a frame.
What is conversion efficiency?
The conversion efficiency expresses the percentage
of light energy from the sun that is actually converted into electricity.
The following formula can be used to calculate the
conversion efficiency of a PV module.*
* Calculation using exterior dimensions with protrusions
omitted.
The ideal PV panel angle from the standpoint of volume
of electricity generated is 30 degrees in Japan. Though there are regional
variations when installation and maintenance are taken into account,
there should be no problem if the roof gradient is between 20 and 40
degrees. This amount of variation from the ideal will only result in
a difference of about 2% in the amount of electricity produced.
Are only roofs with a southern exposure suitable for
installation of PV arrays?
Which direction does your roof face? The amount of
electricity produced differs depending on the orientation of the roof.
Make sure to confirm the orientation of your roof before installing PV
panels. Note that it is also possible to combine panels oriented east
and west, for example, in the same system.
What is the durability and service life of a typical
system?
Service life: Typically, PV modules have a service
life exceeding 20 years. The other equipment used in the system employs
parts with a design service life of about 10 years.
Equipment and System Components
