Page 138 - Alternative Energy Systems in Building Design

114 SOLAR POWER SYSTEM PHYSICS AND TECHNOLOGIES

SHADING ANALYSIS AND SOLAR ENERGY PERFORMANCE
MULTIPLIER
One of the most significant steps prior to designing a solar power system is investigating
a location for the solar platform where the solar PV arrays will be located. In order to
harvest the maximum amount of solar energy, theoretically, all panels, in addition to
being mounted at the optimal tilt angle, must be totally exposed to the sun’s rays without
shading that may be cast by surrounding buildings, objects, trees, or vegetation.
To achieve this objective, the solar power mounting terrain or platform must be ana-
lyzed for year-round shading. It should be noted that the seasonal rise and fall of the
solar angle has a significant effect on the direction and surface area of shadows cast. For
instance, shadows cast by a building or tree will vary from month to month, changing in
length, width, and the shape of the shade. In order to analyze yearly shading of a solar
platform, solar power designers and integrators make use of a commercial shading-
analysis instrument known as the Solar Pathfinder (shown in Fig. 3.60). This instrument

Figure 3.60 Solar Pathfinder and shading graphs. Courtesy of Solar Pathfinder.