Thermal conductivity measurement of oil in Water (O/W) nanoemulsion and oil in H2O/LiBr (O/S) binary nanoemulsion 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 used to prepare the stable oil-in-binary solution (O/S) emulsion. To stabilize the nanoemulsions in a strong electrolyte, four different polymers are 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 found that the measured thermal conductivities of the oil in water (O/W) nanoemulsion and binary nanoemulsion (O/S) with a stabilizer enhance up to 6.4 and 3.6%, respectively compared with the Maxwell's model. It is also found that GA (Gum Arabic) gives the highest thermal conductivity enhancement. It is finally confirmed that the initial stable condition of the O/S nanoemulsion can be recovered by the re-dispersion in actual absorption systems. (C) 2011 Elsevier Ltd and IIR. All rights reserved.