Physical system modelling languages: from Allan to Modelica

Modelling and simulation play a number of roles in engineering design studies. For Gaz de France, these studies must satisfy exacting criteria of quality and rapidity. Studies are even more effective if models developed on previous occasions can be stored and reused and if the company is able to share models with its partners. The development of model exchanges is therefore a key factor determining the future scope of modelling/simulation activities. The Modelica design group was set up to design of a new language for physical modelling. There are already several modelling tools with their own language for object-oriented, non-causal modelling, such as Dymola, gPROMS, MOSES, NMF, Omola, ALLAN and U.L.M. This working group is attempting to unify the concepts and to introduce a common basic syntax and semantics. Gaz de France is very much looking forward to the existence of such a language, shared by different users with different modelling environments. We will present a simlifide model of a water heater in ALLAN and in Modelica.