Many recent proposals for alternative power cycles employ non-azeotropic binary mixtures in a Rankine cycle. Most power cycles cited in the literature are characterized by their high degree of recuperation. However, little information is given in the way these cycles are designed. The objective of this work is to develop a methodology based on heat-exchanger network syntheses to study and optimize the performance of an ammonia-water Rankine cycle. The results of this study show that the design of heat-exchanger networks can have a significant impact on the performance of power cycles.