Numerical study of the effect of using twisted tape and a nanofluid on the thermal performance of a cylindrical-parabolic collector

Cylindro-Parabolic Collector (CPC) is a solar energy technology known for its established role in concentrated solar power systems. Ongoing research aims to improve its thermal efficiency by exploring modifications in the geometry of the absorber tube and using innovative heat transfer fluids. The main objective of this work is to evaluate the combined effects of modifying the absorber tube geometry and using advanced heat transfer fluids on the thermal performance of CPCs. The absorber tube design incorporates twisted tape inserts, which act as turbulators to enhance heat transfer. The heat transfer fluids used include Syltherm 800, a synthetic heat transfer fluid, and Syltherm 800+Cu, a nanofluid that adds copper nanoparticles (φ=1-4% )improved thermal properties. The performance of a collector with a twisted tape turbulator ( CTT) is compared with that of a plain collector tube (PC) by calculating the Nusselt number (Nu) and outlet temperature. The findings results indicate a significant enhancement in thermo-hydraulic performance with the twisted tape turbulator and Syltherm 800+Cu nanofluid combination. The twisted tape increases turbulence, improving heat transfer, while the nanofluid enhances the thermal conductivity of the fluid.