Concentrating solar-thermal (CST) systems with parabolic trough collectors (PTC) can provide low-emission heat and electricity with temporal flexibility. Conventional plants typically deploy numerous temperature sensors for thermal balancing but, for economic reasons, lack sufficient mass-flow sensors to quantify the mass-flow distribution within the solar field.



This work advances the Time-of-Flight method, using commercial power-plant data, specifically for line-focusing CST to determine the mass flow distribution across the solar field. The approach enables straightforward localization of underperforming collectors and, moreover, attribution of losses - for example, distinguishing optical from thermal causes such as vacuum losses. Because the method is simple, safe, cost-effective, precise, and fully non-invasive, it offers substantial potential to enhance the competitiveness of line-focusing CST systems.