This chapter introduces the conventional and latest energy saving technologies for process systems, especially for use in oil refineries and petrochemical plants. One of the most famous energy saving technologies for these processes is a well-known heat recovery technology that uses pinch technology. The hot and cold stream lines can be moved horizontally within the temperature limits in the temperature-heat diagram. Process systems are designed based on this graphical analysis. In contrast, in the latest energy saving technology termed self-heat recuperation technology, the hot stream line is shifted vertically by using the adiabatic compression of the hot stream in the temperature-heat diagram. Thus, the whole process heat can be recirculated into the process without any heat addition, leading to further energy saving in the process systems. In addition, process design methodology based on self-heat recuperation and the overall energy efficiency of the designed process are illustrated using simple thermal and distillation process examples.