Performance assessment of an air-cooled heat exchanger for multiwalled carbon nanotubes-water nanofluids

This study used a two-step synthesis method to prepare multiwalled carbon nanotubes (MWCNTs)-water nanofluids (MWNFs) with a dispersant of sodium dodecylbenzenesulfonate (SDBS) and an evacuation procedure. The basic characteristics of the MWNFs were measured and analyzed. Then, the MWNFs were used in a cooling system with an air-cooled heat exchanger (ACHE) to evaluate the heat exchange capacity, pumping power, and efficiency factor (EF) of the ACHE. The results show that the pumping power of the cooling system increased with an increase in the MWNFs concentration under all experimental conditions; the maximum enhancements of MWNFs at 0.25 wt.% for the heat exchange capacity and EF were approximately 7.77% and 7.53%, respectively, compared with water. However, increasing the concentration of the MWNFs did not increase the heat exchange capacity and EF. The optimal configuration of the MWNF concentration was 0.25 wt.%.