Experimental and theoretical description of a technique for the concentration measurement of binary liquids containing nanoparticles

Nanoparticles are known to enhance both the heat and mass transport properties of fluids in which they are suspended resulting in significant interest for many fields, including refrigeration systems whose efficiency is linked to effective heat and mass transport. Within absorption refrigeration the concentration of the binary liquid is a key component in evaluating the performance during operation. Conventional techniques for concentration measurement rely on properties such as the density or electrical conductivity which are changed when nanoparticles are present. In addition to changing the thermophysical properties by adding nanoparticles, the volume fraction of the nanoparticles changes during a mass transfer process which further complicates the concentration measurement. The method presented here is a density based measurement that incorporates the changing volume fraction of the nanoparticles and concentration of the base fluid. Experiments include LiBr and LiCl solutions containing silver and iron-oxide nanoparticles at multiple initial volume fractions and particle sizes. The method developed is extremely robust and useful, as it is possible to determine the concentration of any unknown sample based only on knowledge of the initial concentration of base liquid and nanoparticle volume fraction when the sample is synthesized.