Investigation on mass transfer characteristics of the falling film absorption of LiBr aqueous solution added with nanoparticles

A set of mathematical models is developed based on energy and mass conservation to predict the mass transfer characteristics of falling film absorption of lithium bromide (LiBr) aqueous solution added with nanoparticles. Experimental measurements are conducted to validate the mathematical models, and good agreement is acquired. Simulations are performed to investigate the mass transfer of LiBr aqueous solution added with nanoparticles. Results showed that nanoparticles could significantly improve the water vapor absorption rate of nanofluid in the process of falling film absorption. Moreover, the water vapor absorption rate increased with the number of nanoparticle additives. With the same number of nanoparticles, the water vapor absorption rate of LiBr solution increased with the solution flow and with the change of solution flow trend for logarithmic curve. The mass transfer enhancement factor also increased with the number of nanoparticles. In addition, the mass transfer coefficient of absorber increased with the number of nanoparticle additives. When the flow rate of nanofluid with 0.05% and 0.1% added nanoparticles was 1.0 L min−1, the mass transfer coefficient increased by 1.28 and 1.41 times, respectively. These results are beneficial in improving the mass transfer of the working medium used for an absorption refrigeration cycle and enhancing the performance of an absorption chiller.