Viessmann Vitovolt 200 Technical Manual page 20

4.3 Glossary
Grid
(public power supply system, national
grid)
The grid joins all power stations and
consumers (network).
Hot−spot effect
The destruction of a solar cell through
heat development when a panel is
partially shaded. This is prevented by
means of bypass diodes.
Idle voltage
Intensity of voltage between the positive
and negative pole of a power source (e.g.
solar panel), when no consumer is
connected.
Inverter
Inverter with mains synchronisation and
mains monitoring, which transforms the
DC current (e.g. solar current) generated
by the solar panel, which is connected to
the power supply system, into
conventional AC current and feeds it into
the grid.
Mains coupling
The connection of decentralised power
generators, e.g. solar power systems and
the grid.
Mains feed system
Contrary to the island system, this system
is connected to the grid and requires no
storage batteries.
Mono−crystalline solar cell
In mono−crystalline solar cells, the
material (silicone) is arranged at the
atomic level in a perfectly regular crystal.
MPP − Maximum Power Point
A point on the panel curve where the
solar generator generates its maximum
output, which depends on irradiation and
temperature.
Output
Momentary output of an electrical
consumer or power generator (power
station, solar heating system), measured
in watts (W) and not to be confused with
electrical power (Wh). The watt peak (W
states the peak output of a solar
generator (cell, panel) under STC.
Partial load range
A photovoltaic system only rarely
produces peak power (kW ), but
p
generally less, depending on the
momentary brightness. This means the
system and its components (inverter)
operate in the partial load range, as they
only produce a portion of their maximum
output.
20
Photovoltaic (PV)
Terminology relating to the generation of
electrical power from solar light.
p−n junction
If a semiconductor is contaminated by
external atoms, the originally
non−conductive material becomes
conductive, i.e. either positive (electron
shortage) or negative (electron surplus). If
two such layers are immediately side by
side, the boundary layer is referred to as
the p−n junction. In this boundary layer an
electrical field is formed inside the
material.
Poly−crystalline solar cells
During manufacture, the material forms
many individual crystals, which can be
recognised by the frosted appearance of
the surface.
Power supply connection point
The connection point of the inverter in the
domestic electrical installation or the grid.
RCD switch
Earth leakage protection in the electrical
installation serving to protect people
against electrical shocks when touching
mains voltage.
Renewable energies
Sources of energy which do not consume
a finite raw material, but tap into natural
cycles, are described as renewable (sun,
wind, hydro power, bio−energy); in most
cases tides, sea currents and geo−heat are
also counted as such sources.
Renewable Energy Act (EEG) [Germany]
The [German] "Act for the prioritising of
renewable energies" (Federal Act)
prescribes minimum payments, terms of
connection and other contractual
conditions for feeding power from
renewable energies into the grid, became
law on the 1 April 2000.
Semiconductor
Material which in its physically pure state,
is non−conductive and can be made
conductive by deliberate contamination.
)
p
Short circuit current
Intensity of current, when the positive
and negative poles of the solar generator
are joined together (short circuit).
Subject to technical modifications.
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Solar cell
An individual element for gaining solar
power, which directly transforms solar
light on the basis of a purely physical
process without any mechanical or
chemical processes and without material
consumption, theoretically offering an
unlimited service life (size approx. 10 x 10
up to 15 x 15 cm).
Solar collector
Component for gaining heat from
sunlight (thermal solar energy).
Solar generator
All solar panels of a solar power
generator system.
Solar hours
Special weather recorders log the hours
of sunshine
sunshine enable the calculation of the
directly irradiated energy
irradiation is the precise value for this
measurement.
Solar panel (photovoltaic panel)
Individual component of a solar
generator. The solar panel electrically
combines many solar cells which are
encapsulated against weather influence.
STC (Standard Test Conditions)
Standard conditions, under which the
electrical parameters of a solar panel are
measured, to enable a comparison
between the products of various
manufacturers.
Thin−film solar panel
The solar cells are made in a
material−saving process by direct vacuum
metallisation onto a carrier material
(glass, stainless steel film), where they
only create a thin layer.
W (watt peak) and kW
p
See output and energy.
Yield factor
States the factor by which a solar
heating/power system yields more energy
during its operation life than was required
for its creation.
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the number of hours
global
(kilowatt peak)
p
VITOVOLT