| HVAC (Heating Ventilation Air Conditioning) system is a control system which can implement the regulation of temperature, humidity, air clean degree and the change of the air circulation through certain control functions. With the further development of building energy saving technology, the clean pollution-free energy sources need to be applied to all aspects of the construction industry. In the field of air conditioning, geothermal resource completely accords with the standard of green energy saving, and it is a renewable new energy. Ground source heat pump air conditioner is a kind of application of geothermal resources in the field of construction. Because this air conditioning system uses geothermal energy, it has the characteristics of new energy application such as clean and no pollution, energy conservation and higher efficiency. Ground source heat pump system can use geothermal energy as a source of environmental refrigeration and heating supply in summer and in winter, respectively. At the same time, it also can be used as a living hot-water supplement source.At present the prominent problems of ground source heat pump air conditioning system are large energy consumption, low efficiency and difficult to extend for its control system. Most important of all, it hasn’t adaptive ability on the control of water flow and room temperature. So these ground source heat pump air conditioning systems are difficult to realize the win-win of air conditioning comfort requirement and. Operation or control of the ground source heat pump air conditioning water systems also has many unreasonable aspects.The purpose of using ground source heat pump air conditioning system is to keep the indoor temperature and humidity meet the requirements of environmental comfort, achieve energy conservation effectively, at the same time. In order to achieve the goal, the rationality and stability of the ground source heat pump air conditioning water system are needed to be improved at runtime. The key to realize the control requirements lies in the improvement of the control performance for water system. The research purpose of this study is to eventually design a set of ground source heat pump air conditioning control system which both can satisfy the comfort requirement of air conditioning, and can guarantee system without waste of energy consumption. Also flow control and temperature control of the system have higher adaptive performance. The main function of the control system is to realize optimization operation of the air conditioning water system in the largest extent. Energy conservation has become a key aspect in the field of green building. The performance improvement of the control system for ground source heat pump air conditioning system is the promotion for the implementation of building energy conservation.The control strategy needed to be resolved in the practical ground source heat pump air conditioning engineering and the research status of neural network in the field of HVAC are studied at present. This study based on the research of the basic control theory, and combined with the control experience of existing operation system. The control characteristic of BP neural network PID controller used in ground source heat pump air conditioning water system was the core content of this study. Finally, the control advantage of the method was took, and the defect and insufficiency of the control characteristic were found. Based on the research, the new control method was designed with the BP neural network PID control method which was improved by the genetic algorithm. Initial parameters of neural network were optimized by the improved genetic algorithm, so as to realize good performance of genetic neural network PID control technique in ground source heat pump air conditioning system. This paper mainly covered the following aspects:Firstly, the development and operation characteristics of the ground source heat pump air conditioning system were summarized and the operation characteristics and disadvantages of traditional air conditioning were analyzed by reading a large number of related literatures at home and abroad. The advantages and application significance of ground source heat pump air conditioning system were explained by comparing the above summary of performance and data. The important influence of ground source heat pump air conditioning water system optimization control technology in the system control and the meaning for its continue study were analyzed. The optimal control methods which were applied in ground source heat pump air conditioning system were summarized. Eventually, a set of control method which had optimization effect was designed for ground source heat pump air conditioning water system.Secondly, the working principle and status of the ground source heat pump were analyzed in depth. The structure of the ground source heat pump air conditioning water system was understood in the round. And the mathematical model which could discusses the problem objectively was established on the basis of the preceding work. This topic used the existing relevant basic theories of variable flow system as the research basis, for the study, In the actual operation, the primary pump variable flow system was used as the research model. And then effective variable flow control methods and strategies of ground source heat pump air conditioning water system were researched in-depth through reasonable modeling and simulation of control theory research methods.Thirdly, in order to make the flow of ground source heat pump air conditioning water system meet the effect of automatic adjustment by changing with user load. In the system, temperature difference control method was mainly adopted for the adjustment of ground source heat pump air conditioning water system. In order to make the temperature difference control method realize the good performance, the BP neural network PID controller and the BP neural network PID control strategy combined with Bang-Bang control were designed for the control and adjustment of the ground source heat pump air conditioning water system. Through simulation experiment, compared with the traditional PID control system, the designed BP neural network PID control system showed better control performance in the system’s robustness and the final running effect. Further on, the BP neural network PID control system combined with Bang-Bang control had especially good control performance. The simulation experimental results showed that the designed BP neural network PID control method and the BP neural network PID control system combined with Bang-Bang control were effective and feasible in ground source heat pump air conditioning water system control.Fourthly, the established BP neural network PID controller was further improved based on the simulation results and the further research of control algorithm. The selection of initial weights values and threshold values for neural network algorithm could influence the performance of the control system. Ultimately genetic algorithm was determined to be adopted to realize the optimization of its initial value. Study design was improved gradually. In final, a set of complete differential pressure control system for ground source heat pump air conditioning water system control was established by the BP neural network PID control algorithm based on the improved genetic algorithm. The results showed the good control performance through the simulation of designed algorithm. This control algorithm was more effective and feasible than traditional genetic algorithm.Finally, the designed ground source heat pump air conditioning water system control methods were analyzed, summarized and compared. Finally, the insufficiencies of this study were analyzed. And the reasonable and feasible solutions were put forward. |
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