Line-focus solar concentration 10 times higher than the 2D thermodynamic limit

Line-focus solar concentrators have traditionally been limited by the 2D concentration limit due to the continuous  translational symmetry in these systems. This limit is orders ofmagnitude lower than the 3D  limit, severely limiting the achievable concentration ratio comparedto point-focus  systems. We propose a design principle for line-focus solar concentrators thatbypasses this 2D  limit, while maintaining a trough-like configuration and only requiring singleaxisexternal solar tracking. This  is achieved by combining the concept of étendue squeezing withthe concept  of tracking integration. To demonstrate the principle, we present a design examplethat achieves a  simulated average yearly efficiency of 80% at a geometric concentration of 335xunder light with a ±9mrad angular distribution and horizontal single-axis  external tracking.
We also show how the same design principle can achieve a line-focus with 1563x geometric
concentration at 90% efficiency if design constraints are relaxed by foregoing tracking-integrationand assuming  two-axis external solar tracking. This design principle opens up the design spacefor high-concentration  line-focus solar concentrators, and may contribute to a reconsideration ofthe trade-off between  concentration and acceptance angle in such systems.