Effects of synthetic oil nanofluids and absorber geometries on the exergetic performance of the parabolic trough collector

The parabolic trough collector is 1 of the most deployed solar concentrating collectors in the world. In this research, the commercially available LS-2 collector has been modeled using the engineering equation solver. The developed model is validated using the experimental results of the Sandia National Laboratory, LS-2 collector test. The study presents a comparison of the exergetic performance of 4 different absorber tube geometry configurations: conventional absorber tube, longitudinal finned tube, absorber tube with twisted tape insert, and converging-diverging absorber tube. The system is analyzed to observe the nature of exergy losses and exergy destruction for the various design configurations with the use of Therminol VP-1 and Al2O3-Therminol VP-1 nanofluids. The results show that the biggest cause of reduced useful work is because of the destructed exergy from the sun to the absorber. While the optical errors account for a higher percentage of exergy losses. The converging-diverging absorber geometry produced the best exergetic enhancement of 0.65% with the use of Therminol VP-1 and 0.73% with the use of Al2O3/Therminol VP-1 nanofluid.