aleo
aleo solar Deutschland GmbH
| Osterstraße 15| 26122 Oldenburg |
Germany
installation instructions Edition 01/2012 en-GB-Intl (120508b)
Page
51
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60
Fig. 37 Avoidance of a full shadow by an edge (shadowing only
by half shadow, diagram)
Avoidance of a half shadow
Avoid the half shadow of an edge by moving the solar module
upward, opposite the line of sight of the sun/edge.
If the lower edge of the lowest cell of a module is
above
the
line of sight of the 'sun/cell lower edge' by at least this
displacement, the module will not be struck by a full or a half
shadow.
RECOMMENDATION
To determine the minimum height displacement h
PE
of
the lower edge of the lowest cell of the solar module
above the line of sight of the sun/edge (e.g. a flat roof)
with a clearance a
K
, the same formula can be used:
h
PE
= a
K
/ 214
Fig. 38 Avoidance of a full and half shadow by an edge
(diagram)
This is relevant, above all, for the height of the midday sun at
the time of the winter solstice, as the horizon height of the
sun at around midday is low and only changes slowly. The
lower edge of the shadow is therefore at its maximum height
and can strike parts of the photovoltaic generator for long
periods.
The shadow cast by edges located at a distance in a horizon-
tal direction (e.g. the upper edge of the flat roof on which the
photovoltaic generator is installed) is less critical as it only
strikes shortly after sunrise or shortly before sunset and
therefore only negligibly reduces the yield.
Example
The ridge of a neighbouring building is located, in the line of
sight of the sun/edge, 8.56 m from the lower edge of the
lowest cell of a solar module. Therefore, there are the
following options to avoid shadowing:
Full shadow avoidance:
The lower edge of the lowest cell can be at the most 4 cm
below the 'sun/roof edge' connection line, so that even in an
extreme case
15
the lowest row of cells is only in the half
shadow cast by the edge.
Half shadow avoidance:
The lower edge of the lowest cell should be at least 4 cm
above the 'sun/roof edge' connection line, so that even in an
extreme case, the module is neither in a full nor a half shadow
cast by the edge.
15
The midpoint of the sun, as viewed from lowest cell, is
located exactly on the roof edge.
a
PE
UM
h
K
h
PE
K
GID AS006a
a
K
h
>
a / 214
GID AS007a
PE
UM
h
K
K
h
h
K
h
PE
