Diagnosis of an air conditioning system by stochastic qualitative reasoning

A diagnosis using qualitative reasoning is applicable to the diagnosis of building air conditioning systems such that their configuration is various. In this technique, a target system is modeled qualitatively, and possible patterns of behaviour of the target model are generated by the qualitative reasoning. By comparing the results of reasoning with the real measured values, a faulty part is identified. We propose a stochastic qualitative reasoning method. In this method, the existence probability is introduced to prevent the increasing possible behaviours of the model. Through the qualitative reasoning process, the states having negligible probability are eliminated. We have applied this method to fault diagnosis of a building air conditioning system and confirmed its effectiveness.<>