The present study describes the technique of Flow Network Modeling (FNM) and its application for the design of an air-cooled server. The technique of FNM involves representation of the flow system as a network of flow paths and components for the prediction of system-wide flow and bulk temperature distribution. The FNM technique is very efficient in terms of the effort required for model definition, solution, and examination of results because it employs overall component characteristics for analyzing their system-wide interaction. Further, use of empirically measured component characteristics ensures good accuracy of the predicted flow distribution. Application of this technique for the design of an air-cooled server involved investigation of the flow distribution in different system layouts, generation of ideas for performance improvements based on predicted system-wide flow distribution, and evaluation of these modifications on the air-flow performance of the system. Use of FNM is shown to significantly reduce the time required for a comparative performance evaluation of different system configurations. Such rapid analysis enabled development of a good system design during the Conceptual Design Stage, before the design proceeded to a stage where changes are very costly to implement. An enhanced design cycle is outlined that uses FNM analysis during the early design stage for shortening the overall design process, enhancing the quality of the final design, and improving the productivity of the thermal design engineer in a significant manner.