Page 133 - Solar Power in Building Design The Engineer's Complete Design Resource

SITE EVALUATION 103

Figure 4.10 The Solar Pathfinder showing the remov-
able shading graph, the leveling bubble at the center and
the compass. Photo courtesy of Solar Pathfinder.

the true magnetic pole) to orient the device toward the true magnetic pole. Pulling
down on the small brass lever allows you to use the center triangle to pivot or rotate
the shading pattern toward the proper magnetic declination angle.
Global magnetic declination angle charts are available through magnetic declination
Web sites for all countries. U.S. magnetic declination maps can be accessed at www.
ga.gov.us/oracle/geomag/agrfform.jsp. For Australia, go to www.ga.gov.au/oracle/
geomag/agrfform.jsp. For Canada, go to www.ga.gov.ca/oracle/geomag/agrfform.jsp

Site Evaluation

Perhaps the most important step when undertaking a solar power design is to thor-
oughly investigate the site conditions. This section discusses the items for which the
solar platform where PV units are to be installed must be evaluated.

Roof-mount solar power systems For roof-mount systems evaluate the roof-
mount obstacles such as heating, ventilating, and air-conditioning (HVAC) or air-
handling units, vents, roof-mount chiller, ducts, surrounding trees and buildings, parapets,