Operation Optimization Of Distributed Variable Frequency System At The End Of Heating Pipe Network In Chengde City

With the development of my country’s urbanization process,the scale of urban central heating continues to grow.The traditional central heating system can no longer meet the current demand.Based on this situation,a distributed variable frequency heating system has been produced.Compared with the traditional heating system,this system could effectively improve the operating efficiency of the heating system;reduce the energy consumption of water pumping and the operating cost of the system.Therefore,it is very necessary to carry out research work related to the operation strategy of the distributed variable frequency heating system.First of all,this paper analyzes the pump operation efficiency and energy consumption based on the actual operation data of the distributed variable frequency system in the eleven heating stations at the end of the pipeline network of the Chengde central heating system.The problem analysis is carried out in combination with the equipment situation of each thermal station and the heating demand of the secondary network.Although the in-use pump-valve coupling control scheme can meet the basic heating demand of the district,the following problems still exist: The primary network flow of some thermal power stations has different degrees of hydraulic imbalance,and the actual heating load has a large deviation from the index heat load.In some thermal stations,the selection of water pumps,pump speed and valve opening configuration are unreasonable,resulting in low operating efficiency and high energy consumption of the water pumps in the system.The heating load of the system cannot change in real time with the outdoor temperature.The above problems provide guidance for optimizing operating parameters,carrying out related simulation and theoretical research.Secondly,based on the actual equipment parameters of the above-mentioned distributed variable frequency system,this paper establishes a mathematical and physical model with Flowmaster as the platform.A theoretical analysis of the system’s pipe network characteristics and water pump energy consumption under actual operating conditions is carried out.The model was verified according to the actual operating parameters,and the parameters of the system flow,pressure and energy consumption were consistent with the actual operating data.The data shows that the model has high prediction accuracy.The optimized schemes is based on the in-use pump-valve joint control scheme,and try to make the water pump operating point in the high-efficiency zone,achieved by adjusting the speed of the variable frequency pump and the opening of the electric control valve.Compared with the in-use solution,after the system adopts the optimized solution,the operating performance of the pump has been significantly improved.During the entire heating season,the power consumption per unit heating area decreased from 0.889 k W·h to 0.763 k W·h,and the total power consumption was saved by14.16%,and the energy saving effect was significant.Finally,this article introduces a pump control scheme based on the principle of water pump frequency conversion regulation(the electric control valve is fully open,and the speed of the frequency conversion water pump is changed under any working conditions),and the power consumption of the system frequency conversion water pump is simulated and analyzed.The results show that compared to the pump-valve joint control scheme,the system adopts the pump control scheme to achieve better energy-saving effects.When the system is in a deep-cold heating period with a large temperature difference between day and night,it is advisable to adopt a time-based pump control scheme.Compared with the in-use solution,this solution can effectively reduce the heating load during periods of high outdoor temperature,and the indoor temperature of typical users has been significantly improved,and the total daily power consumption of the system can be saved by 17.76%.In summary,the rotation speed of the water pump and the opening of the valve in the heating pipe network are the key factors for energy saving in the heating system.In this paper,by continuously optimizing the speed of the variable frequency pump in the heating power station,the total power consumption saving rate of the system is obtained.The research results have important reference significance for the operation and control of the actual heating system in Chengde.