Thermal conductivity enhancement of binary nanoemulsion (O/S) for absorption application

Binary nanoemulsions, oil-droplet suspensions in binary solution (H2O/LiBr), are developed to enhance the heat and mass transfer performance of absorption refrigeration systems. In this study, a novel four-step method is proposed to prepare the stable oil-in-binary solution (O/S) emulsion. To stabilize the nanoemulsions in a strong electrolyte, a polymer (Gum Arabic) is used as a steric stabilizer. The droplet size and the thermal conductivity of binary nanoemulsions are measured by the dynamic light scattering method and the transient hot-wire method, respectively. It is concluded that the ratio of 2:1 (oil:surfactant) is the best condition to obtain the distribution stability. It is also found that the measured thermal conductivity of the binary nanoemulsion with a stabilizer enhances up to 3.6% compared with the estimated one from the Maxwell's model. It is finally proposed that the thermal conductivity of the binary nanoemulsion could be enhanced by adding nano-sized droplets of n-decane oil, which has a lower thermal conductivity than that of the base fluid.