[Elsevier] Effect of hybrid and single nanofluids on the performance characteristics of chilled water air conditioning system Copy

In this work, the performance characteristics of a vapor compression refrigeration system associated with a chilled water air conditioning unit utilized nanofluids (Al2O3, TiO2, and a hybrid of Al2O3/TiO2 based H2O) were experimentally investigated.

The tested parameters were; nanoparticle concentration, nanoparticle type, nanofluid flow rate, nanoparticle hybridization ratios, and air velocity. The study incorporated different concentration ratios of nanoparticles 0.05, 0.1, 0.2, 0.3, 0.4, 0.6 and 1% for Al2O3/H2O whereas 0.1, 0.3, 0.4, 0.6 and 1% for TiO2/H2O. Five different concentrations of hybrid nanoparticles Al2O3/TiO2 were employed by 0.1/0.1, 0.2/0.1, 0.3/0.1, 0.3/0.2 and 0.3/0.3 wt%. Experiments were done at air velocity ranging 0.61–1.9 m/s whilst the fluid flow rate was varied by 0.12–0.3 m3/s. Experimental results indicated that the single nanofluid of Al2O3/H2O contributed a higher coefficient of performance and a lower elapsed time for cooling the fluid of a chiller system. Higher values of the VCRS coefficient of performance were obtained at lower values of air velocity of air conditioner and higher values of the nanofluid flow rate of the chiller unit. The Al2O3/H2O provided lower values of compression ratio and higher values of the refrigeration effect in comparison with TiO2/H2O by approximately 4.1% and 5.3%, respectively.