Simulation And Research On Fault Detection And Diagnosis Of A Quench Air Conditioning System

In this paper, the characteristics of automatic control on the quench air conditioning systems is introduced briefly, and the significance of those systems' normal operation to the production of synthetic fiber is detailed. Based on the researches and applications to fault detection and diagnosis of HVAC field around the world, the parameters model of supply air temperature control subsystem (SATCS) of the quench air conditioning system is proposed by integrated utilizing research achievements in the identification field, and the fault detection and diagnosis software of the system are developed. The detailed works of this paper mainly include such things as follows:1. Analyses the process of heat and humidity and air mix in the components of the quench air-handling unit, derives the general form of mathematics model of the SATCS from equations of thermal balance.2. Gets the dynamic response curve of the processes and parameters of the cooling water three-way valve PID controller by the simulation to the control parts of dew-point temperature. The parameters have high reliability because of the out-door air temperature fluctuation being considered in the simulation model.3. Integrated utilizing research fruits on the system identification and a set of data obtained from normal operating conditions, build the parameter model of SATCS. The ARX model whose reliability is highest is choosen by comparing the residuals from model output of ARMAX, ARX and IV4. Determine the orders and time-delay of model by test the equation error. The things such as identifiable, on-line identification, and measure data preprocessing are all considered.4. According to the technique route "mathematics model—simulation—build model from identification—on-line identification of the model's parameters", studies and develops the FDD software of quench air system in summer, which successfully detects a thermometer fault according to simulation curve, on-line parameters and experiences of the workers. We can concludes that it can detect not only the faults which is easily found by workers, such as thermometer's failure, but the actuator faults difficultly found by the operators in site, such as the damper sticking, when applied in quench air conditioning system.