Description induced by modelisation methods in the case of building thermal simulation

Two main modelisation techniques are the analytic and systemic methods. After a presentation of  each method applied to building simulation, this paper emphases the benefit of systemic modelisation for  multizone cases. Using a conceptual description of a  building issued of previous method, one particular  sub-system appears naturally, i.e. the thermal zone.  Then, the physical coupling of thermal zones can simply  be solved. Building description through data structures, required for thermal simulation, is easily reached. The  detail of our organisation is given in the case of our  multiple model software, CODYRUN. Because of our  resolution sheme, the main problem is the establishment  of a thermal zone model. So, the computer generation of one zone nodal model is explained.