Comparisons of mechanical and chemical treatments and nano technologies for absorption applications

The objectives of this paper are to investigate the effects of surfactant and surface roughness on absorption performance, to apply binary nanofluid to the absorption system, and to compare the effects of three technologies on absorption performance. In order to compare the effect of surface roughness and that of surfactant, two micro-scale hatched tubes and a bare tube are tested on the H₂O/LiBr falling film absorber with the addition of n-Octanol 400 ppm in the first experiment. The effect of binary nanofluid is compared with that of surfactant on NH₃/H₂O bubble absorption performance in the second experiment. The results show that the absorption performance for the micro-scale hatched tubes with surfactant becomes up to 4.5 times higher than that for the bare tube without additive, the addition of 2-Ethyl-1-Hexanol 700 ppm can enhance the NH₃ absorption rate 4.8 times, and the addition of Cu nano-particles 0.1 wt% can enhance it 3.2 times. It is concluded that the absorption enhancement by the surfactant is more significant than that by the micro-scale hatched tubes in the H₂O/LiBr falling film absorber, and the effect of nano-particles on the absorption performance is comparable to that of surfactant in the NH₃/H₂O bubble absorber.