Thermal and energy management prospects of γ-AlOOH hybrid nanofluids for the application of sustainable heat exchanger systems

This study focuses on double-tube heat exchanger (DTHE) to numerically examine their thermal performance by considering two types of hybrid nanofluids: (i) TiO 2 -γ-AlOOH/water and (ii) TiO 2 -γ-AlOOH/ethylene glycol. γ-AlOOH is an efficient material for heat transfer application. The heat exchanger consists of two tubes, which are called the inner and the outer tubes. The coolant and the hot oil, respectively, flow into the inner and the outer tubes. The volume proportion and volume fraction of nanoparticles are 90:10 (γ-AlOOH/TiO 2 ) and from 0.1 to 0.5%, respectively. The rates of mass flow, alongside the heat transfer rate and the pumping power, are evaluated. The employed model to solve the governing equations is a multiphase mixture, validated with earlier reports. The boundary conditions are reliable for industry deployment. When TiO 2 -γ-AlOOH/water is employed rather than TiO 2 -γ-AlOOH/EG, 50% improvement in heat transfer rate is obtained. It is noted that TiO 2 -γ-AlOOH/EG possesses a higher (30%) pumping power than TiO 2 -γ-AlOOH/water. However, to estimate the energy consumption in industrial scale, an additional analysis on pumping power of heat exchanger with EG-based coolants are needed in the future. Graphic abstract