This paper considers the relative merits of three optimization objective functions for the design of an energy efficient pervaporation membrane network for ethanol dehydration: the minimization of the standard deviation of the thermodynamic driving force, of the entropy generation, and of the power of separation. The resulting designs are compared with those of a standard numerical optimization minimizing the total exergy consumption of the compressors and heat exchangers. Results reveal that in terms of total exergy consumption, the equipartition af all three functions give results close to the reference case. However, in terms of the distribution of the membrane surface areas, the equipartition of the power of separation gives results closest to the reference case.This paper is an updated version of a paper published in the ECOS'09 proceedings.