Energy and Exergy Performance Optimization of Heat Exchanger with Turbulators and CQD Nano Coolant Using Taguchi-Grey Approach

Abstract

In the present work, the optimization of energy and exergy performance was carried out using the Taguchi-Grey relational analysis method in a heat exchanger (HX)  featuring turbulators and carbon quantum dot (CQD) nano-coolants with various base fluids [Water (W), ethylene glycol (EG), and propylene glycol (PG)]. The most important parameters, such as the Reynolds number (4000 to 8000), HX types (PT, TI inserted, PTI inserted), and CQD nano-coolants (CQD PG, CQD W, CQD EG), were analysed in terms of the Nusselt number, heat transfer rate, pumping power, friction factor, COP, and entropy generation rate. Taguchi analysis carried out to determine the optimum situations showed that the highest Nusselt number and heat transfer correspond to 8000 Reynold number, PTI-inserted HX, and CQD-PG; the lowest pumping power and entropy were found at 4000 Reynold number, PT HX, and CQD-W; the maximum COP was observed at 4000 Reynold number, TI-inserted HX, and CQD-PG; and the minimum friction factor was at 8000 Reynold number, PT HX, and CQD-W; the overall performance was found to be at 8000 Reynold number, PTI-inserted HX, and CQD-EG. The variable that notably influenced the friction factor, entropy, and power is Re, and HX significantly affected the COP and heat transfer. These insights have immense industrial potential in the areas of automotive radiators, HVAC, and power plant condensers by way of compact, energy-efficient designs.