Fault Detection And Diagnosis Of Variable Air Volume's End-device Which Is Based Upon Fuzzy Theory

Sustainable development has always played an important role in China's strategic planning.Energy conservation is the top priority for sustainable development.With the development of science and technology,all kinds of energy consumption surged,building energy consumption accounted for 30% of the total energy consumption of the society,and the energy consumption of heating,ventilation and air-conditioning reached 50% of the building energy consumption.For large centralized air conditioners,the occurrence of faults may cause the system to run oscillating,which in turn leads to an increase in energy consumption.Accurate and rapid diagnosis of faults is of great significance to the stable operation of the system and energy saving.VAV air conditioning system due to the existence of variable air volume meter allows the system can be based on changes in the room load and flexibility to change the amount of air into the room to achieve the effect of energy saving,so the variable air tank fault diagnosis is particularly important.Accurately mastering the fault information of the variable air volume box has a guiding role in the prediction before the failure and the exclusion after the failure.In view of the practical significance of the research on the fault diagnosis of the VAV air conditioning system's terminal device,this paper first elaborates the actual background of the project and analyzes the necessity of the research.The characteristics of VAV air conditioners and the advantages compared to fixed air volume air conditioners are introduced,and the working principle of VAVBOX is described.Explained the impact of the occurrence of VAV failure on the entire system.Then analyzes the current situation in the field of air conditioning fault diagnosis at home and abroad,combined with the fault characteristics of the VAV air conditioning terminal device,the final choice of the fuzzy diagnosis(FUZZY)theory as a research tool.The operating data of the normal operating conditions were collected on the VAV experimental platform.The CUSUM accumulation and the sensitivity of the graph to the minor deviations were used to diagnose the occurrence of faults and the fault detection was completed.Then introduced the TRNSYS simulation software,enumerated the mathematical model of each part,straightened out the logical relationship between them,established the wind system of variable air volume air conditioning,and verified the simulation platform by comparing the simulation experimental data with the measured data.Correctness.Then simulate the fault at the end of the variable air volume on the simulation platform,analyze the change trend of the characteristic parameters when the fault occurs,find the mappingrelationship between the fault and the symptom of the fault,and obtain the sample set of the fault.Fuzzy mathematics model of fault diagnosis was established by fuzzy diagnosis method.Fault data was collected and simulated on the simulation platform to verify the model.Finally,the possible causes of the faults are proposed and the methods of elimination are given.The experiment and simulation study of this paper show that the research on the faults of VAV air-conditioning end-devices helps to improve the stability of the system,expands the expert knowledge base,and has a positive effect on the saving of building energy consumption.