PVsyst supports simulations with many plane orientation modes:
| - | Fixed tilted plane: you just have to define the Plane tilt and azimuth. |
| - | 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). |
| - | Seasonal tilt adjustment: the plane tilt may be adjusted with two values, for winter and summer chosen months. |
| - | 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. |
| - | 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. |
| - | 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. |
| - | 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°. |
| - | 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. |
| - | 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). |
| - | Tracking sun-shields: is a particular case of the Tracking, horizontal E-W axis. It may yield solutions causing difficult optimization between sun protection and PV production. For full efficiency, this should involve a Backtracking control strategy. |
| - | 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. |
| - | 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 in terms of the sun's position.
With horizontal or tilted axis trackers, you can also use a strategy that 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 used is rather low (lower GCR).
The Backtracking control strategy that adjusts the orientation to avoid mutual shadings at any time, may help optimize 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 the construction of the 3D shading.
