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 zones. Then, the physical coupling of thermal zones, can simply be solved. Building description through data structures, required for thermal design, 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.