Experimental study of heat and mass transfer for ammonia-water falling film absorption on novel S-shaped capillary tubes bundle

Compact absorber is beneficial for bulk reduction and cost-saving of absorption systems. This paper presents an experimental study on the heat and mass transfer performance of a novel absorber which consists of an S-shaped capillary coils bundle. Experiments were carried out for a practical ammoniawater absorption system under practical working conditions. The effects of operating parameters such as degree of subcooling, concentration and mass flow rate of inlet solution, as well as absorption pressure, on absorption were investigated. Specifically, with the selected pressures of 300kPa, 400kPa and 500kPa and concentrations of inlet solution of 6.6%, 15.5% and 22.4%, we obtained the heat and mass transfer coefficients ranging from 622 similar to 1945 Wm(-2) K-1 and 5.1 similar to 34.3 x10(-6) ms(-1), respectively. The heat and mass transfer experimental data were processed in terms of the empirical correlations for the Nusselt and Sherwood numbers, respectively, and the correlations can fit all the experimental data with error bands of +/- 15%. (C) 2020 Elsevier Ltd. All rights reserved.