Research On Heating System Regulation Based On Dynamic Response

With the rapid development of China’s central heating system,the continuous increase of central heating area,heating energy consumption is increasing,heating energy saving is particularly important.On the one hand,it is necessary to save energy as much as possible,on the other hand,it is necessary to ensure the heating demand of users,that is,during the heating period,the heating amount of heat source should match the heat consumption of users,and the heat consumption of users is mainly affected by outdoor meteorological conditions.With the change of outdoor meteorological conditions,the system needs central heating regulation,no matter which way of adjustment,it is to change the system temperature or flow.For the precise adjustment of heating system,it is necessary to change the flow or temperature of a certain branch in the heating system,and the response process and time of relevant heating parameters of other branches and key places in the heating system are essential.In this paper,the dynamic model of heat exchange station and heat supply network is established,and the model is used for simulation calculation.Finally,the reliability and accuracy of the model are verified by practical engineering.The main research contents are as follows:Firstly,the regulation mode of central heating system is analyzed;the dynamic response characteristics of heating system under different regulation modes(quality regulation and changing flow quality regulation by stages)with the change of load are analyzed,and the basic formula of heating regulation is given,and the dynamic response index of control theory is introduced into the dynamic response research of heating system.Secondly,based on the knowledge of fluid mechanics and heat transfer,the relationship between energy transmission and heat transfer of each part of the heating system is analyzed,and the dynamic model of heating system is established,including the dynamic model of heat exchanger and the dynamic model of pipe network.The model is solved by programming,and the model is verified by the measured data of heating regulation in the actual project.Then,the influence of pipe diameter,pipe length and flow rate on the dynamic characteristics of the pipe network is analyzed through the simulation calculation of the model.Finally,the actual project is tested and the test data are sorted out.The reliability of the dynamic model is verified,and the dynamic response characteristics of the heating network in the heating system are further analyzed through the actual engineering test.The results show that under the same pipe network and flow rate,the delay time,rise time and regulation time of different water supply temperature are consistent for the same point,but the farther away from the heat exchange station,the longer the delay time and regulation time;under the same heating pipe network,the greater the flow rate,the shorter the delay time and regulation time of heat supply temperature at the end of pipe network.When the circulating water pump is 47 Hz,the delay time of point a at the farthest end of the measuring point is 500 s and the regulating time is 850s;the delay time of point d at the nearest end of the measuring point is 300 s and the regulating time is 600 s.When the time delay of the most distant regulating point is 500 s,the time delay of the pump is 300 s.No matter what heating regulation,the rise time remains the same,which is 300 s.In conclusion,large flow and short distance are beneficial to reduce the delay time of water temperature at the end of pipe network.It can be seen that the research on the dynamic characteristics of heat supply network can provide support for control system regulation and heating system design.