Fault Prediction And Diagnosis Of The Water Side Of Groundwater Source Heat Pump System

The application of the GWSHP technology is the important measures to realizescientific energy utility and to solve the problem of energy shortage in our country. Inrecent years, GWSHP system has been widely used in architecture field and itsdevelopment was very rapid. But when this technology popularized in architecture fieldof our country, it exposed some problems in technology, design and operationmanagement. Establishing a complete fault diagnosis system is the necessary measuresto ensure that the GWSHP system can operate stably and efficiently. However, becausethe GWSHP system using the groundwater as its cooling or heating source, so it existssome faults that other types of heat pump don’t have. As a consequence, it is hard forthe traditional heat pump fault diagnosis method to be fully applied in the GWSHPsystem.For the sake of making up the blank in the study of heat pump system faultdiagnosis, avoiding the occurrence of faults in GWSHP system water side and ensuringthe GWSHP system working sustainably and efficiently during the operation period,this paper studied the faults in GWSHP system water side, such as injection wellsclogging and heat breakthrough, and focused on the fault evolution prediction anddiagnosis on the basis of fault detection in traditional method.As for the problem of injection well clogging, firstly, this paper analyzed the typesand the causes of injection well clogging, proposed a general method to forecast anddiagnose injection wells clogging in GWSHP systems. Secondly, we applied thisdiagnose method to compute permeability coefficient and the period of time that injection well overflow of different wells by measuring the water level and the flow rateof each well in some residential quarter of Yangling district, on this basis, judged thedeterioration degree of the injection performance by the deterioration percentage ofpermeability coefficient and judged the possibility of injection well overflow during theoperation period by the period of time that injection well overflow of different wells.Finally，this paper gave prevention measures of injection well clogging.As for the problem of heat breakthrough, this paper firstly elaborated the heattransfer mechanism when the groundwater moved in the aquifer and used numericalsimulation method to analyze influence factors of heat breakthrough. Secondly，thispaper established the artificial neural network which can realize the prediction anddiagnosis of heat breakthrough and proposed the assessment criteria which can evaluatethe influence of heat breakthrough to the GWSHP efficiency. Judged the occurrence ofheat breakthrough by the temperature rise and judged the weakened degree of theGWSHP efficiency during the operation period by assessment criteria. Finally, thispaper verified this diagnosis method by the four years’ operating data of someresidential quarter of Yangling district and proposed the prevention measures of heatbreakthrough.