Research On Fault Diagnosis Of Small Air Cooling Heat Pump Unit

The fault of the refrigeration equipment causes problems such as the poor customer service experience,the waste of energy,the reliability of the system,and the short service life.For this reason,the domestic and foreign scholars have done a lot of effective researches on the fault diagnosis of refrigeration equipment,especially large-scale water-cooling water unit and HVAC system.The small air-cooled heat pump unit has been widely used in the field of air conditioning,frozen,refrigeration,and industrial special refrigeration,and the number of its equipment is huge.daily maintenance and fault maintenance is an important job of the user units.Timely detection and diagnosis of this kind of equipment early fault,has important practical significance and engineering research application value.The research on fault diagnosis technology of small air-cooled heat pump unit is designed to explore a more effective diagnosis.The specific work is as follows.(1)In this paper,the model of a small air-cooled heat pump unit is used as a research object,and an analysis of the split floor heat pump air conditioner regulator cooling system which cooling capacity is 7.2k W.The type and acquisition position of the data collection is designed,which introduces the 15-road temperature,the 4-channel pressure sensor,and the computer program,which is compiled by Agilent.Complete the construction of the test table and the collection and storage of all kinds of parameters.(2)Through the system to set up the bypass electronic expansion valve,valve opening,paper coverage,the simulation of the compressor exhaust gas,four-way valve leakage,liquid pipeline block,heat exchanger table area of dirty traffic,and so on,to obtain a large number of fault data,further analyze the correlation between the acquisition parameters and the fault state,introduce the principal component analysis,reduce the dimension of the sample data,and reduce the correlation between the data.In order to make the fault feature more clear,the model is beneficial to the separation and recognition of the fault,shorten the diagnosis time and improve the diagnosis accuracy.(3)For the extension theory has the characteristics of formal,logical and mathematical,it provides a method to deal with problems qualitatively and quantitatively.By introducing the extension theory,a diagnostic model based on extension theory was established to formally describe the sample data of the generating units and to classify the faults using the correlation function criterion.The experimental results show that the model can effectively identify the five types of faults that are studied above.But it is not entirely accurate to distinguish the fault of the exhaust of the compressor and the leakage of the stone valve.The reason is that the basic extension matter-element model input is dependent on the data of the fault sample data,and it is necessary to optimize the associated function.(4)In order to solve the problem of low accuracy or lack of diagnosis,the immune algorithm is introduced,artificial immune system has the advantages of self-learning mechanism,self-learning,self-non-self recognition and other advantages,combined with the extension matter-element model,the establishment of an extension immune algorithm diagnosis model.The design and training of B-cell diagnosis element model,by increasing the information space of the fault diagnosis,has established a more accurate quantitative expression for the classification of affinity.It is proved that the diagnosis method based on the extension immune algorithm can achieve the diagnosis of the typical fault of small air-cooled heat pump unit,with high accuracy and effectiveness.