Different ways to improve parabolic trough solar collectors’ performance over the last four decades and their applications: A comprehensive review

This paper presents an extensive review of experimental, numerical, and numerical-experimental studies focused on compiling different aspects that lead to improved PTSC performance using the different electronic base sources during the last four decades. Different applications and future research prospects have also been presented, guiding the researchers that focus on developing new working fluids, receiver configurations, applications, among other aspects for PTSC performance enhancement. Experimental studies reveal that the combination of nanofluids and turbulators leads to the best improvement in PTSC thermal efficiency, followed by the use of internal fins and nanofluids only. Numerical studies affirmed that fin inserts have a more significant influence on heat transfer than nanofluids, but its main drawback is that it has a cost increase of 5%. The dispersion of Cu and CuO in the base fluid showed a remarkable increase in the heat transfer coefficient than other nanoparticles. Therefore, they are the best options to improve the PTSC's performance. Numerical-experimental studies reveal that the tube with an internal annular porous combined with the nanofluid Al2O3/Synthetic oil showed the best increase in thermal efficiency with a value that varies from 8% to 15%. Electronic analysis of publications focused on improving the PTSC's performance shows that China participates with 25%, followed by India with 11%. The PTSC applications proved that it is ideal for electrical energy stability and less dependent on limited fossil fuel reserves. Furthermore, more experimental studies are required to mature nanofluids' application and new receiver tube configurations on an industrial scale.