Étendue and angular acceptance of the asymmetric compound parabolic concentrator

Although the use of the asymmetric compound parabolic concentrator (ACPC) for solar concentration has been addressed, documentation regarding étendue and angular acceptance of the ACPC is absent from the literature. This paper delves into the two-dimensional design of the ACPC and discusses its étendue and angular acceptance, offering a design tool regarding such instances when symmetry is broken. It is found that unlike the compound parabolic concentrator whose angular acceptance fills a symmetric ellipse, the ACPC’s angular acceptance fills an asymmetric ellipse in some cases and a folded ellipse in others. Both cases are dependent on the maximum acceptance angles of the design. Ray tracing is utilized to confirm the angular acceptance ellipses and étendue, as well as to offer a visual representation of the intensity distribution for asymmetric designs in both angular and phase spaces.