Thermal exergo-economic investigation of heat exchanger assisted with inserts under CQD nanofluid

Rapid development in recent machinery requires a serious heat eradication system to fulfil the energy demand and improve compact heat exchanger performance. The passive approach is employed to accelerate the rapid heat removal processes and thermal efficiency. The present paper investigates the energy, exergy, and sustainable economic development of a compact Heat Exchanger (HX) operated with water, Ethylene Glycol (EG), and Propylene Glycol-based Carbon Quantum Dots (CQD) nanofluid assisted with two modified geometrical inserts, Turbulator Insert (TI) and Perforated Turbulator Insert (PTI) in a plain tube. The thermophysical properties of the coolant and HX performances have been evaluated using a mathematical model. Results show that the use of geometrical inserts with nanofluid significantly enhances the thermo-economic parameters of the compact heat exchanger. The passive PTI inserts in the core of the plain tube operated with CQD-PG nanofluid result in 11.7% higher overall heat coefficient, 10.4% higher exchange of exergy, and a superior Sustainable index at a lower Reynolds number. The heat transfer rate of HX with PTI and CQD-PG nanofluid results in 9.5% higher, and with TI, 8.5% higher than without inserts. In the meantime, PTI geometrical inserts require 93.3% higher operating cost with CQD-PG nanofluid. The operating cost of CQD-PG is found to be 17.4% than CQD-EG nanofluid. This work is the first to integrate passive heat transfer inserts with CQD nanofluids in HX. It offers a comprehensive framework for maximizing heat exchanger performance while guaranteeing economic viability by fusing thermal, exergy, and economic evaluations. The results have broad implications for sustainable engineering solutions and energy-efficient thermal systems.