Evaluation of γ-Al2O3/n-decane Nanofluid Performance in Shell and Tube Heat Recovery Exchanger in a Biomass Heating Plant

The performance of a ?-Al2O3/n-decane nanofluid shell-and-tube heat exchanger in a biomass heating plant is analyzed to specify the optimum condition based on the maximum heat transfer rate and performance index for wide range of nanoparticle volume fraction (0–7%). Compared with pure n-decane, the obtained results in this research show that by using ?-Al2O3/n-decane nanofluid as the coolant at optimum values of particle volume concentration for maximum heat transfer rate (?=0.021) and for maximum performance index (?=0.006), the heat transfer rate and pumping power increased by 10.84%, 13.18% and 6.72%, 2.3%, respectively. Increasing particles concentration raises the fluid viscosity, decreases the Reynolds number and consequently decreases the heat transfer coefficient. As a result, determining the optimum value of the particle volume fraction of nanofluid as the working fluid, can improve the performance of shell-and-tube heat exchangers.