Page 39 - Design of Solar Thermal Power Plants
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32 1. INTRODUCTION
b
c
a
FIGURE 1.16 Geometrical dimensions of heliostat.
a a
b b
c c
FIGURE 1.17 Geometrical dimensions of parabolic trough concentrator.
17. Receiver aperture area. The maximum receiver flat area that
accepts concentrated solar radiation. This is the area of the flat
surface defined by the outer perimeter of the receiver, including
nonactive zones (if any) between adjacent receiver elements
composing the receiver. For receivers without a secondary
concentrator and composed of several parallel tubes, it is given by
the product of the total length of each tube and the total width of
the receiver. For receivers without a secondary concentrator and
composed of a single tube, it is given by the product of the total
length and the diameter of the receiver tube (excluding the glass
cover, if any). For receivers with a secondary concentrator, it is given
by the product of the total length of the receiver and the width of the
aperture area of the secondary concentrator. For cavity receivers, it is
the flat surface associated with the aperture of the cavity.
18. Concentrator performance requirements.
While the concentrator is receiving and reflecting solar energy,
there exist specular reflectance losses, including specular loss,
Cosine loss, shading and blocking loss, atmospheric attenuation loss,
