Energy-Economic and Exergy-Environment Performance Evaluation of Compact Heat Exchanger With Turbulator Passive Inserts Using THDNF

Abstract

Technology innovation requires advanced heat transporting techniques to fulfill better exergy and economic behavior of compact air heat exchangers (HXs). Three different turbulator inserts, TTIs, PTTIs, and DTTIs (twisted turbulator inserts, perforated twisted turbulator inserts, and dimpled twisted turbulator inserts, respectively), are used in air HX on the tube side as a passive technique for heat transfer enhancement. The present investigation deals with the exergo-economic with a sustainable analysis of air HX utilizing several water-based tripartite hybrid nanofluids (THdNFs), formed from three different nanoparticles intermixing, six different compositions based on the structure of nanoparticles, and three various turbulator placed to the tube core of HX. The detailed investigation of 4Es and sustainability of the device are investigated under various operating conditions. Results disclosed that nanofluid alone is not enough for energy and exergy improvement. However, turbulator passive device inserts in HX with THdNF show a remarkable improvement in thermal and thermohydraulic performance. The DTTI passive device in plain tubes using THdNF 5(Al2O3 + TiO2 + graphene–water) results in the highest 27% overall coefficient, 24.7% exergy change, 6.4% exergy efficiency, 7.4% performance index, and higher sustainability index at lowest Reynolds number than without inserts. Meanwhile, turbulator inserts yield to most increased 91.4% operating cost and equivalent CO2 emissions to the environment. Investigation revealed that the passive device DTTI with THdNF 5(Al2O3 + TiO2 + graphene–water) as a working fluid is likely to be preferred due to the highest performance evaluation criteria (PEC) ranges 2.3–2.45 for the same power, and the least preferred working fluid would be THdNF 2 (Al2O3 + Fe2O3 + SiC–water) due to its high operating cost.