An optimization methodology, based on process integration techniques, is applied on a high temperature PEMFC based micro-CHP simulation model to improve its performance, in terms of net electrical efficiency and total HEN cost. This is accomplished by solving two objective functions: (1) maximization of the net electrical efficiency of the system, (2) minimization of the total HEN cost. The first optimization strategy includes a pinch analysis and process change procedure. Pinch analysis is applied on the initial set of stream data, and then by use of the plus–minus principle (process change), the system is optimized with a genetic algorithm optimization methodology. This approach is diverse, because it allows studying and evaluation of the optimum system