Performance of single phase natural circulation loop using hybrid nanofluids for heating above 100°C
In the present work, various thermal oils and glycols (Therminol VP-1, Paratherm-CR, Dowtherm Q, Dowtherm A, Ethylene glycol and Propylene glycol) based hybrid nanofluids have been used as working fluid in single phase natural circulation loop (SPNCL) applicable for heating temperature range of 100-200°C. Considered fluids are compared based on performance parameter such as mass flow rate, effectiveness and entropy generation. Influence of nanoparticle volume fraction and heating power on the performance parameter are studied. The two nanoparticles Al2O3 and Ag of equal volume ratio are suspended in base fluids to prepare hybrid nanofluids. The result illustrates that the mass flow rate and effectiveness are enhanced with nanoparticle volume concentration whereas entropy generation rate decreases. Hybrid nanofluid improves the performance of SPNCL. Maximum increment in mass flow rate (9.7%) and effectiveness (59%) whereas maximum decrement (24%) in total entropy generation is observed for Paratherm-CR based hybrid nanofluid at 2% volume fraction compared to base fluid. Within considered fluids, the Paratherm-CR based hybrid nanofluid is found to be best because it has highest mass flow rate and effectiveness, lowest entropy generation rate for studied operating range.