DESCRIPTION

r.suntrack combines elements of r.sun and r.pv to calculate computes beam (direct), diffuse and ground reflected solar irradiation raster maps and optionally the photovoltaic (PV) system energy output, for a PV system mounted on a suntracking surface. For the details of the solar radiation calculations, see the r.sun documentation. For the details of the PV model and model coefficients, see the r.pv documentation.

r.suntrack and its sister modules r.pv and r.sunyear are part of the PVMAPS software package. This package consists of these GRASS modules together with scripts giving examples of how to run the modules, and, most importantly, a large amount of input data to run the modules.

All options are the same as for r.sun or r.pv except the numaxes option described in the following.

Like r.sun, r.suntrack can calculate either the solar irradiance for a single time and day, or it can calculate the total irradiation for one day. r.suntrack can calculate the solar radiation on a number of different tracking surfaces. The choice of tracking type is given by the option numaxes, which may take the following values:

  1. plane moving around a single horizontal axis oriented north-south. This plane will face eastwards in the morning, face straight up (be horizontal) at noon and westwards in the evening.
  2. True two-axis tracking, whereby the normal of the plane is always pointing directly toward the sun.
  3. Plane mounted on a single vertical axis, at an angle to the ground. The inclination angle of the plane is fixed and rotated around the axis so that the plane faces east in the morning, south (north in the southern hemisphere) at noon and west in the evening.
  4. Plane moving around a single horizontal axis oriented east-west. This plane will always face south (north in the southern hemisphere) but the inclination of the plane changes during the day and with the seasons.
  5. plane moving around a single inclined axis oriented north-south. This plane will face eastwards in the morning, face south (north in the southern hemisphere) at noon with the inclination angle of the axis, and westwards in the evening. Option 1 can be seen as a special case of this option, with the inclination angle set to 0.

All other options except numaxes are the same as for r.sun or r.pv.

REFERENCES

See also references in the documentation of r.sun and r.pv