Exploitation of the bond graph methodology's unified modelling approach over many energy domains has enabled a comprehensive, generic, computer-aided conceptual design tool (Schemebuilder) to be developed. This paper describes how bond graph fragments representing individual components are assembled into complete system models from which steady state performance and dynamic simulations may be computed. It is concluded that the bond graph methodology provides an excellent basis for the concurrent conceptual design of interdisciplinary products through to the generation of a “rapid prototype”