<p>This study presents a three-dimensional (3D) numerical investigation of a novel receiver configuration of an LS-2 parabolic trough collector (PTC). It is enhanced by a dodecahedron lattice structure inserted inside the absorber tube. The lattice insert functions as a passive heat transfer enhancement strategy for PTCs. The objective is to evaluate its thermo-hydraulic performance while accounting for the associated pressure drop. Simulations were performed using ANSYS Fluent with Syltherm 800 as the heat transfer fluid. The conventional absorber tube was compared with three lattice structure configurations: a full lattice, an upper half-lattice, and a lower half-lattice. Three lattice edge thicknesses of 0.7, 1.2, and 1.7&#xa0;mm were also examined. The results show that the full lattice configuration provides the best performance. Increasing the lattice edge thickness enhances the Nusselt number ratio from 5.04 to 14.89, accompanied by increases in the relative friction factor from 4.84 to 16.19 and the performance evaluation criteria (PEC) from 2.98 to 5.89. This offers a favorable balance between heat transfer improvement and pressure drop penalty. The thermal efficiency increases from 65.11% for the conventional absorber tube to 69.18%, 77.24%, and 92.99% for the three lattice edge thicknesses, respectively. These findings demonstrate that incorporating an additively manufactured lattice structure into the absorber tube substantially improves the thermo-hydraulic performance and thermal efficiency of the LS-2 PTC, offering a promising design route for high-performance solar thermal systems.</p>