Page 68 - Design of Solar Thermal Power Plants

60 2. THE SOLAR RESOURCE AND METEOROLOGICAL PARAMETERS

The azimuth angle of surface normal can be either 90 or 90 degrees,
which is determined by the symbol of solar azimuth angle; namely:

g ¼ 90 ; if g 0

s
(2.14c)
g ¼ 90 ; if g < 0

s
For a surface that continuously revolves by surrounding a northesouth
axis parallel to Earth’s axis and is required to revolve to the point where
the solar incidence angle is of minimum value at a specified time, the
corresponding incidence angle equation is:
cos q ¼ cos d (2.15a)
The continuously changing surface slope angle is:
tan f
tan b ¼ (2.15b)
cos g
The corresponding azimuth angle of surface normal is:
sin q z sin g s
1

g ¼ tan þ 180 C 1 C 2 (2.15c)
cos q sin f
0
In which:
0
cos q ¼ cos q z cos f þ sin q z sin f (2.15d)
8

0;
> 1 sin q z sin g s
s
< if tan þ g ¼ 0
0
C 1 ¼ cos q sin f (2.15e)
>
1; else
:
1; if g 0

s
C 2 ¼ (2.15f)
1; if g < 0
s
A surface that continuously conducts double-axis tracking is always
capable of incident solar radiation perpendicular to the surface, and thus:
8
> q ¼ 0
<
b ¼ q z
>
g ¼ g s
:
2.5 DISTRIBUTION OF THE SOLAR RESOURCE IN
SEVERAL TYPICAL AREAS OF CHINA
In order to facilitate the understanding of readers, we would now like
to introduce the solar energy resources in Beijing, Lhasa, Golmud, Dun-
huang, Turpan, Guizhou, Hainan, and Harbin.