Direct methanol fuel cell (DMFC) systems are mostly composed of massive water recycling devices such as coolers, condensers or mixers even for small and light portable applications. Integrated systems, where system components serve more than one function, can be equipped with fewer components and have a lighter weight than conventional ones. However, the process integration can also bring about significant methanol evaporation in separators, resulting in low fuel efficiency. The here presented highly integrated system can minimize methanol loss with optimized concentration control to improve efficiency. Two system variants are compared with regard to concentration, temperature, water recovery controllability and efficiency. The simulation results are compared with the previously published mingled-outlet system and validated with experiments. (C) 2017 Elsevier Ltd. All rights reserved.