Stochastic qualitative simulation of heat source system

In the heat source system (HSS), the circulating water transmits heat to provide warm or cold air for every room of a building. In order to ensure that the system is operating in good condition, it is necessary to detect its malfunctions. However, owing to the constraint of cost, it is impossible to use enough sensors to obtain numerical information for troubleshooting of such a complex system. And the various, vague and changeable structure of each building air conditioning system makes it difficult to formulate the physical relations between its components. The paper presents the stochastic qualitative simulation method for fault diagnosis of such a system as HSS. In this technique, the complex structure of HSS is expressed qualitatively with only abstracted components and causal relations between them. On the basis of its qualitative models, its behaviors are analyzed to pinpoint the cause of the fault. We introduce the feedback function to acquire the most appropriate description of the HSS. Using the field data, several malfunctions were successfully detected