Systematization of an energy saving grass-root design and retrofitting technology based on process integration is a subject of increasing interest in plants running under the batch mode of operation. In this work, the solution to the product changeover problem is studied in order to achieve a feasible and optimized heat exchance network design for multiproduct batch plants. A new methodology is presented which is based on : (a) the campaign-mode of plant operation; and (b) the study of energy integration for each campaign. The concept of Macronetwork is also introduced. This includes the heat exchanger network of all campaigns in an overall design, and contemplates the common matches between networks of campaigns of different products. Algorithms to obtain the best feasible matches and energy targets are presented and results of test-case studies are discussed to illustrate this methodology.