PVsyst supports simulations with many plane
orientation modes:
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Fixed tilted plane: You just have to
define the Plane
tilt and
azimuth. |
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Multi-orientations: you can define PV planes for up to 8
different orientations. You have to associate a different
electrical sub-array to each orientation. You also have the
possibility of sharing strings of one inverter on two different
orientations (see
Mixed Orientations). |
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Seasonal tilt adjustment: the plane tilt
may be adjusted with two values, for winter and summer chosen
months. |
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Unlimited sheds: To be used when the sheds are
very long with respect to their width. If the sheds are too short
as one cannot neglect the edge effects, you should define sheds in
the "Near shadings" CAO option instead. |
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Unlimited sun-shields: Same remarks as for sheds. The
optimization of electrical yield of sun-shield systems is very
difficult, and only suited for south façades. |
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Tracking, tilted axis: the axis tilt and azimuth should be
defined (the axis azimuth will usually be around 0, i.e. near the
south in northern hemisphere). The rotation angle is called Phi
(value 0 when plane azimuth = axis azimuth), with the same
sign conventions as for plane
azimuth. Mechanical limits on the Phi stroke are
required. |
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Tracking, horizontal N-S axis: this is the usual configuration of
horizontal axis tracking systems. You should use the "Tilted axis" option (above), with axis
tilt = 0°. |
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Tracking, vertical axis: the collector is
kept at a fixed tilt, but rotating according to the sun azimuth.
This configuration may be used with "dish" arrangements, when a big
rotating support holds several rows of modules; this particular
case is made possible as the rotating axis of one row may be
displaced with respect to the collector. |
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Tracking, horizontal E-W axis: the orientation
axis is defined as the normal to
the horizontal axis. This configuration is here for completeness,
but is indeed not suited for PV systems. Stroke
limits should be defined (here Phi = plane tilt), from lower limit
(minimum -90° = vertical north) to upper limit (maximum 90° =
vertical south). |
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Tracking sun-shields: is a particular
case of the Tracking, horizontal
E-W axis. It may yield
solutions to the difficult optimization between sun protection and
PV production. For full efficiency this should involve a
Backtracking control strategy. |
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Tracking, two axes: the limit mechanical
angles of the tracking device (in tilt and azimuth) should be
defined, and are taken into account during the simulation. |
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Tracking, two axis with frame: the
collectors are fixed and rotating within a frame, itself rotating.
This is therefore a variant of the 2-axis
tracking. Two configurations are available: a frame with
North-South axis (and collectors with tracking tilt) or a frame
with East-West axis (and collectors tracking according to the sun
azimuth). |
Remarks and Limitations
The tracking strategy in computed using the
solar geometry (so-called "astronomical"
algorithms), in order to minimize the incidence angle as
function of the sun's position.
With horizontal
or tilted axis trackers, you can also use a strategy which
optimizes the irradiance on the tracker. See
Tracking strategies.
For sheds, please carefully see the special
combination of "Orientation" option and "Near shadings"
treatment
Also be aware that with tracking planes, the
mutual shadings of several neighbour tracking units can become very
important at extreme angles (see the
shed optimization tool with very tilted collector
plane!). The collector's spacing should usually be very
large, so that the horizontal space use is rather low (lower
GCR).
The
Backtracking control strategy, which adjusts the
orientation to avoid mutual shadings at any time, may help
optimizing the electrical shading effects. However, even if there
is no mutual shadings for the beam component, the mutual
shading on the diffuse and albedo components should be
evaluated. This requires that the 3D shading scene must be
constructed in any case.
