The Fault Detection On Groud-Source Heat Pump Of Central Air Condition System

With the development of society, people's standard of living were greatly improved, the needs of thermal comfort were also increased. As the creator of comfortable living environment, the central air-condition system played an important role. so the system were more and more complexity and the fault occurred frequently. The work of fault detection was greatly challenged, and how to establish effective fault detection system was the problem present to us.Currently, the researches are mainly about certain devices and lack of the whole system fault detection. The method used for fault detection was very single, each method had many shortcomings. Most researchers had developed their own fault detection software, which had great limitations and can only be applied to some fixed air-condition systems. At the same time, the communication between people and fault detection system was poor, so the fault can not be updated in time.In response to this situation, this paper studied the fault on the entire system and combined fault-tree model and the generalized fault tree of knowledge representation method, then analysis and field test were conducted on ground-source heat pump with vertical buried-pipe loop of central air-condition system, and the fault tree models were established. Then the qualitative analysis on fault tree model was conducted and the minimal cut sets of fault tree were received. According to the minimal cut sets, the parameters of the air-condition system were concluded. By analyzing these parameters, the existing faults and the potential faults can be identified effectively; it provided a reference on how to keep the system operated steadily. Then the "overheating" in air-condition room in summer was described by the fault tree diagnostic framework, the rules and experimental methods of fault diagnosis were given for the following programs. In the end, the test was conducted on the air-conditioning system of a sales department, after theoretical analysis and field testing, the fault tree of "overheating" and "the vents were wet with dew" in air-conditioning room in summer were validated, the experimental results showed that the constructed fault trees were valid.