Heat Transfer and Exergy Analysis of a Shell and Tube Heat Exchanger using PGW based ZnO Nanofluids

Abstract

In this experimental work, ZnO nanoparticles were synthesized using the chemical precipitation method, and the nanoparticle structure and morphology were characterized through XRD and SEM. Heat transfer and exergetic characteristics were then studied in a shell and tube heat exchanger using PGW-based ZnO nanofluids varying nanoparticle volume concentration and nanofluid (shell side) flow rate at 6, 8, 10 and 12 litres/min. The hot water flow rate was fixed at 12 litres/min. The experimental results show that the heat transfer rate was improved by increasing the nanoparticle concentration and nanofluid flow rate. When the nanoparticle volume concentration was 0.3 per cent, the maximum enhancement of heat transfer rate and average heat transfer coefficient using ZnO nanofluids were 35.9 per cent and 40.2 per cent, respectively, in comparison to the base fluid. Exergy loss and dimensionless exergy loss both increased with nanofluid flow rate and dropped substantially with increased nanoparticle volume concentrations. The average increment of exergetic effectiveness at three different nanoparticle volume concentration (0.1%, 0.2%, and 0.3%) are 10.68%, 23.64%, and 31.23% respectively. The highest exergetic sustainability index (0.41) and lowest environmental impact factor (2.42) were observed when the nanoparticle concentration was 0.3% with the nanofluid flow rate of 6 litres/min.