Abstract
This study analyses the joint influence of aperture width and rim angle on the optical performance of a parabolic trough collector (PTC). Using Tonatiuh-based Monte Carlo ray tracing, 52 configurations combining aperture widths of 3–6 m and rim angles of 30°–150° were assessed under normal incidence. Average heat flux and flux distributions were used to identify favourable geometries, while ray-number convergence and optical-error sensitivity were assessed for the highest-performing configuration. Average heat flux increased with rim angle up to an intermediate optimum and then decreased due to focal broadening and spillage. The optimum rim angle was 100° for aperture widths of 3, 4, and 5 m, producing maximum average heat fluxes of 21,501.6, 28,453.8, and 35,145.7 W/m², respectively. For the 6 m aperture, the optimum shifted to 110°, yielding 41,279.8 W/m². Results observed with 10,000 rays deviated by at most 1.14% from 50,000-ray reference cases. For the 6 m–110° configuration, a 2.5 mrad slope error combined with ±16 mrad tracking errors reduced average heat flux by nearly 67%. The wide-range sweep, convergence check, and error analysis differentiate nominal optima from robust designs, demonstrating that aperture width and rim angle must be optimized jointly and that accurate manufacturing, alignment, and tracking are essential.