Details of an ICS unit developed by the author are presented here (Kalogirou,
1997). The system employs a non-imaging CPC cusp-type collector. A fully
developed cusp concentrator for a cylindrical receiver is shown in Figure 5.5.
The particular curve illustrated has an acceptance half angle, c, of 60° or a full
acceptance angle, 2c, of 120°. Each side of the cusp has two mathematically
distinct segments, smoothly joined at a point P related to c. The first segment,
from the bottom of the receiver to point P, is the involute of the receiver’s circular cross-section. The second segment is from point P to the top of the curve,
where the curve becomes parallel to the y-axis (McIntire, 1979).