Homogenization of solar furnace concentrated flux over a cylindrical receiver

Secondary mirrors (SM) can significantly enhance the homogeneity of the flux produced by solar concentrators, reducing thermal gradients in receivers. Two cases of Secondary Mirror designs are proposed here to uniformize the flux of a solar furnace over a cylindrical reactor: an elliptic cone and a flat-faceted mirror. The axis of the cylindrical reactor is perpendicular to the optical axis of the concentrator, a problem not previously addressed in the literature, where part of the challenge is the transformation of the point-focus flux into a line-focus distribution by the SM. Monte Carlo Ray Tracing simulations were employed to evaluate the optical performance and optimize the proposed secondary mirrors in terms of flux uniformity and optical efficiency. Additionally, a computational fluid dynamics analysis was conducted to assess the impact of flux homogenization on the reactor’s temperature distribution and overall thermal efficiency. The faceted SM was more effective for homogenization than the elliptic cone, increasing uniformity by more than 80% and reducing peak flux by more than 90%. Furthermore, the thermal analysis confirmed that the optimized flux distribution of both types of SM leads to significantly reduce thermal gradients. • Point-focus concentrated flux homogenized over a perpendicular cylindrical receiver. • Elliptic cone and faceted trough secondary mirrors optimized for a solar furnace. • Point-focus concentrated flux partially transformed into line-focus flux. • Flat-faceted secondary produces 84.3% uniformity and 71.7% optical efficiency. • The faceted mirror reduces thermal gradients by up to 86%.