Skip to Content
Find More Like This
Return to Search

FirstOPTIC Software Package for Parabolic Trough Evaluation

National Renewable Energy Laboratory

Contact NREL About This Technology


PDF Document PublicationASME Article (900 KB)

Technology Marketing Summary

Parabolic trough collectors are one of the main concentrating solar power (CSP) technologies used in commercial utility-scale power generation plants. A key param­eter for trough performance evaluation is the collector optical efficiency, which is the ratio of the absorbed solar power by the receiver to that intercepted by the collector aperture. This has a direct influence on annual electricity generation, annual plant revenue, and, eventually, the levelized cost of energy (LCOE).

The factors determin­ing a trough collector’s optical performance include the sun shape, various system optical/geometrical errors, and physical properties of system components. Optical performance is often evaluated using either a simple but low-accuracy analytical probability-approximation method, or an accurate but potentially time-consuming ray-tracing technique.


The National Renewable Energy Laboratory (NREL) has developed a new, fast, and accurate analytical method for the optical evaluation of parabolic trough collectors: First-principle Optical Intercept Calculation (FirstOPTIC). FirstOPTIC employs first-principle optical treatment of collector optical error sources and derives analytical mathematical formulae to calculate the intercept factor of a trough collector and the optical efficiency when combined with optical material properties. The analyti­cal nature of the method makes it suitable for fast and accurate evaluation of large sets of collector design options, while the first-principle treatment of optical error sources inherent in this method yields high accuracy. In the future, FirstOPTIC may be naturally extended to other types of CSP technologies such as linear Fresnel collec­tors and central receiver towers.

  • Fast
  • Accurate
Applications and Industries
  • Solar Thermal
  • Parabolic Trough
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
NREL SWR 13-10PrototypeAvailable10/14/201310/14/2013

Contact NREL About This Technology

To: Jean Schulte<>