Page 121 - Alternative Energy Systems in Building Design

GROUND-MOUNTED PV MODULE INSTALLATION AND SUPPORT 97

Ground-Mounted PV Module

Installation and Support

Ground-mounted outdoor PV array installations can be configured in a wide variety of
ways. The most important factor when installing solar power modules is the PV module
orientation and panel incline. A ground-mounted solar power installation is shown in
Fig. 3.46.
In general, maximum power from a PV module is obtained when the angle of solar
rays impinge directly perpendicular (at a 90-degree angle) to the surface of the panels.
Since solar ray angles vary seasonally throughout the year, the optimal average tilt angle
for obtaining the maximum output power is approximately the local latitude minus
9 or 10 degrees (see App. B for typical PV support platforms and hardware and
App. A for tilt-angle installations for Los Angeles, Daggett, Santa Monica, Fresno, and
San Diego, California).
In the northern hemisphere, PV modules are mounted in a north-south tilt (high-end
north), and in the southern hemisphere, in a south-north tilt. Appendix A also includes
U.S. and world geographic location longitudes and latitudes. To attain the required
angle, solar panels generally are secured on tilted prefabricated or field-constructed

Figure 3.46 Typical ground-mounted solar power system
installation. Photo courtesy of DPW Solar.