Page 109 - Solar Power in Building Design The Engineer's Complete Design Resource

GROUND-MOUNT PHOTOVOLTAIC MODULE INSTALLATION AND SUPPORT HARDWARE 79

of random-access memory (RAM), and a 60-gigabyte (Gbyte) hard drive. The oper-
ating system should preferably be based on Windows XP or an equivalent system
operating software platform.

Wireless transmission system specification. Data communication system hard-
ware must be based upon a switch selectable RS-232/422/485 communication
transmission protocol, have a software selectable data transmission speed of
1200 to 57,600 bits/s, and be designed to have several hop sequences share mul-
tiple frequencies. The system must also be capable of frequency hopping from
902 to 928 MHz on the FM bandwidth and be capable of providing transparent
multipoint drops.

ANIMATED VIDEO AND INTERACTIVE PROGRAMMING
REQUIREMENTS
A graphical program builder must be capable of animated video and interactive
programming and have an interactive animation display feature for customizing the
measurements listed earlier. The system must also be capable of displaying various
customizable chart attributes, such as labels, trace color and thickness, axis scale,
limits, and ticks. The interactive display monitor should preferably have a 30- to
42-in LCD or light-emitting diode (LED) flat monitor and a 17- to 24-in touch
screen display system.

Ground-Mount Photovoltaic Module
Installation and Support Hardware

Ground-mount outdoor photovoltaic 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-mount solar power installation is
shown in Figure 3.15.
In general, the 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 optimum aver-
age tilt angle for obtaining the maximum output power is approximately the local
latitude minus 9 or 10 degrees (see Appendix B for typical PV support platforms and
hardware and Appendix A for tilt angle installations for the following cities in
California: Los Angeles, Daggett, Santa Monica, Fresno, and San Diego).
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 are generally secured on tilted prefabri-
cated or field-constructed frames that use rustproof railings, such as galvanized
Unistrut or commercially available aluminum or stainless-steel angle channels, and