Thermal integration is an important element in the planning and design of chemical engineering processes. This is especially true when energy optimisation is embedded in a software environment permitting unimpeded data transfer and exchange between the design elements can take place in a straightforward and intelligent manner, i.e. in a manner supporting the user. These advantages are demonstrated for a selected process. Expert systems which can extract data relevant for thermal integration from the process data and hence generate an entry data set for subsequent processing in a thermal integration program have proved to,be particularly advantageous. in addition, the process engineer also has the possibility of modifying the data manually and undertaking appropriate adaptions and corrections. Subsequent analysis of thermal Integration (e.g. by the pinch method) often suggests improvements extending beyond the pure thermal regime and lead process flow chart.