The mechanisms of surfactant admixture effect on heat and mass transfer were studied experimentally at steam absorption by a salt solution at operation of the heat pump absorber. Steam absorption by initially immobile water solution of lithium bromide with additives of n-octanol with concentrations of 25400 ppm (both lower and higher than the solubility limit) was studied. Thermograms of a layer surface, moving during absorption, were obtained by thermal imaging equipment. Data on surface tension of lithium bromide solution with small additives of n-octanol was analyzed. (C) 2008 Elsevier Ltd. All rights reserved.