UI-Kennlinienmeßgerät für Solarmodule und -generatoren


UI-Kennlinienmeßgerät für Solarmodule und -generatoren

PVPM Users Manual Page 52

Slope of the roof

For the optimum use of solar radiation the sun rays should fall on

the collectors in a right angle. The optimum elevation and angle

of setting-up correspond to the geographical latitude of a

location. (Freiburg is located on the 48. degree of latitude;

Lübeck on the 54. degree of latitude) Since the sun stands

higher in the summer than in the winter it depends on in which

time of the year the solar equipment is predominantly being

used. Photovoltaic plants for example carry the highest yield on

long summer days, while thermal solar plants are taken to

support heating installations in the winter. As a rule of thumb for

the angle of setting up a latitude of -10° in the summer and a

latitude of +10° in the winter is considered to be effective.

Not to be confused with the slope is the orientation (azimuth) to

the south. In practice smaller deviations from the optimum slope

or orientation decrease the productivity insignificantly. A

temporary clouding of the collectors impairs the effectiveness far


13.3 DC

Short for direct current, as it is being produced by solar cells and

modules and stored by the battery. If many solar cells are

connected in series to a module, the voltages mount up.

13.4 Degradation characteristic

The degree of efficiency of amorphous solar cells declines at the

beginning of the phase of irradiation rapidly and first stabilises

after 3 weeks to 5 month. Next to this irreversible degradation,

another reversible degradation is taking place. That means

amorphous solar cells have a better degree of efficiency in

spring-/summer-time compared to autumn/winter.

PV-Engineering GmbH

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