The Research On Fault Detection And Diagnosis Of Chiller Plants

The energy consumption of heating,ventilation,air-conditioning and refrigerating(HVAC&R)systems plays a significant role in national economy. Especially,the large-scale chiller plants,which serve for modern public buildings, are the chief energy consumption terminals.When the chiller plants are existence of faults,it will decline the coefficient of performance(COP),and also the comfort levels for building occupants.Therefore,it is essential for large-scale business operated water-cooling chiller plants to carry out fault detection and diagnosis(FDD) and make them optimization conditions.The objective of this research work is to develop a robust physical law model-based FDD methodology for chiller plants. Consequently,the complicated refrigeration system can carry out FDD as much as possible on using existing sensors,tranducers and other hardware rather than requiring those installed specially for this purpose.The faults survey for large-scale water-cooling chiller plants are obtained at first in the paper.The fault occurrence of chiller plants components are surveyed through fully field investigation,and then the faults rates and lifetimes are analyzed with statistical theory,therefore,the faults distribution rules are acquired.Secondly,based on the thermodynamic first and second laws,the faults characteristic parameters(CQs)and faults indexs(FIs)are generalized and drawn by reasonable simplification chiller plants operation process.Therefore,the static state FDD models are established for the large-scale evapor compressed chiller plants combination the CQs and FIs.The practical dynamic operation data are pretreated so as the established static state models can detect and diagnose the chiller plants faults during the real operation conditions.Thirdly,the FDD tool has been developed with modeled mathematic models in order to verify the preciseness and validity of the chiller plants.The FDD tool has been programed and verified with established models.The field experiment data with large-scale chiller plants are utilized to analyze FDD tool.The performance diversifications under different fault conditions are analyzed with HXC165A as example.By comparison the rules of characteristic parameters under the fault and fault-free conditions,the threshold value of alarm and termination conditions have been obtained as well.Therefore,the parameters monitoring during the FDD is also significant for the chiller plants performance optimization. Lastly,the faults modification and reliability indexes are discussed and analyzed with reliability theory.Especially,the economic effect during the FDD for chiller plants are analyzed as well,which argues the grand meaning of FDD,and also bring the paper better logicality and continuity.