Under CopyrightPruvost, HervéHervéPruvostEnge-Rosenblatt, OlafOlafEnge-Rosenblatt2023-01-052023-01-052022-05-24https://publica.fraunhofer.de/handle/publica/430627https://doi.org/10.24406/h-43062710.1061/9780784483893.09410.24406/h-430627Many developments and research have led in last decade to enhanced building automation systems embedding data analytics algorithms and performing energy-optimized building systems control. The presented approach aims at providing a complementary analysis layer compared to such systems by the means of semantic modeling and knowledge reuse. For that purpose, it relies on a semantic description of a building energy system from which energy conservation measures can be derived. Starting from an ontological description of the building energy system, an expert system is proposed that provides a monitoring plan and operation advices to building users and managers. This system consumes for a part real-time building data gathered during its operation. For another part, it relies on information about the built-in technical systems, which is usually available in initial design models. The resulting software application might be used in the future as an add-on to existing building management systems and for easing their configuration.enDDC::000 Informatik, Informationswissenschaft, allgemeine Werkeconference paper