An integrated knowledge approach for conceptual equipment design

This paper addresses two real life engineering design problems . A main design problem is the synthesis task : given a requirements specification and an unsatisfactory design, how should this design be changed in order to fullfil the specification ? When a satisfactory design has been found, it is often the case that only the values that describe this design are stored . Because all information about the origin of these values is lost, reuse of (parts of) the design is difficult and the same design problem is solved many times . In this paper we describe a design system for heat exchanger design that automates and gives support for the main design tasks : synthesis, analysis and evaluation. Heuristic synthesis rules, qualitative and quantitative models have been integrated for use in the synthesis and analysis tasks . Causal graphs are used to justify the origin of variable values . The system is equipped with explanation and advisory facilities . The design modifications proposed by the heuristic rules can be questioned, and in certain cases these rules are justified by the numerical models . Further, the system uses the qualitative model to help the designer in finding its own modifications . Finally, explanation facilities are present to trace the origin of design values, if necessary back through several design alternatives .