Effects of hybrid nanofluids and turbulator on efficiency improvement of parabolic trough solar collectors

The simultaneous use of turbulators and nanofluids as the working fluid is an effective strategy for improving the thermal performance of parabolic solar collectors (PTCs). In the present study, a three-dimensional numerical simulation was used to investigate the effects of using a turbulator and adding hybrid nanoparticles on the heat transfer rate and entropy generation in a parabolic trough collector. Two types of turbulators are used, one of which is completely new. The heat transfer coefficient, friction coefficient, thermal entropy, viscous entropy, and Bejan number are also studied. Conical helical gear rings used as discs in the absorber tube have shown that the heat transfer increases by 35.7% compared to the case without turbulators. Also, in this case, the total entropy generation decreases by 32.8%. In all cases, the Bejan number is greater than 0.9, which indicates the pre-dominance of thermal entropy generation.