Air condition energy saving diagnostic system and air condition energy saving diagnostic method based on ontology

The present invention discloses an air condition energy saving diagnostic system and an air condition energy saving diagnostic method based on ontology. A to-be-diagnosed abnormal phenomenon is received. If the reception is empty, air condition performance indicators are diagnosed. If the reception is an abnormal phenomenon, the abnormal phenomenon is converted and generated into a query file, and then the query file is used to query an ontology repository to obtain an inferential diagnostic result. If the corresponding diagnostic result is not found directly by using the query file, the query file is semantically expanded to generate an inferential query file. Next, the inferential query file is used to query the ontology repository to obtain an inferential diagnostic result. Finally, the inferential diagnostic result is presented to a user and the diagnosis ends. The method can be reused by any forms of the air condition system, thereby reducing development costs and improving reusability of knowledge.