This work focuses attention on the contribution of the excess Gibbs function of the working pair to the performance of the absorption cycle. Using water/triethylene glycol, water/glycerol, water/diethylene glycol, water/glycol and water/ sulfolane as working pairs, respectively, the exergy analysis and simulation for the absorption heat transformer show that the maximum excess Gibbs function of the working pair is an essential description of the cycle performance to assess new working pairs. However, this work modified Morrissey and Odonnell's assertion (Morrissey AJ, Odonnell JP. Endothermic solutions and their application absorption heat pumps. Chem Eng Res Des. 1986; 64: 404-6) and proposed that the systems exhibiting the negative deviation from the Raoult's law may be valid within an appropriate range, one or several systems may exist, and their performances overpass others. (C) 2001 Elsevier Science Ltd and IIR. All rights reserved.
