Study On The Operation Strategy Of Active On-demand Heating Of Secondary Pipe Network In Urban Residential District

With the gradual expansion of the scale and complexity of urban central heating system,energy waste and uneven heating have occurred from time to time.At present,China still does not achieve on-demand heating in a large scale.Under the background of vigorously promoting green and low-carbon environment and realizing "carbon neutrality" as soon as possible,how to improve the efficiency of central heating system and reduce energy consumption is an important topic for current research.As the pipe network between the main heating pipe network and the users,the secondary pipe network is very important in the heating system,but its poor stability leads to the frequent occurrence of hydraulic and thermal imbalance.In order to save energy and operation regulation costs,this paper analyzes the principle,characteristics and application environment of variable frequency regulation of water pumps based on the operation rules and heat consumption characteristics of residential buildings in Beijing,and conducts a specific study on the quality regulation of pump frequency modulation and staged flow change in the secondary pipe network control strategy,which is different from the traditional method of dividing flow interval by changing pump,This paper adopts the interval division method of pump frequency conversion to control the flow of each interval,and further optimization has great potential in energy conservation and emission reduction and efficiency improvement.First of all,on the basis of theoretical analysis,the PID controller is used for simulation.Based on heat transfer and various parameters of the heating room,the transfer function of the room model and the variable frequency pump model is established,the indoor temperature and fluctuation range are set,and the simulation results under different control methods are given,including the secondary pipe network water supply temperature,indoor temperature,heat consumption,etc.Compared with the energy consumption and economy of different regulation methods,the quality regulation with staged flow change has better energy saving advantages.Compared with the traditional quality regulation method,the operating energy consumption is reduced by 9.5%.Secondly,use Flowmaster to build a complete platform for system engineering design,establish a complete dynamic simulation model according to the PID control analysis results and the actual operation of a heating station and the secondary pipe network in Beijing,study the heating characteristics of quality regulation that changes the flow in stages,and conduct real-time monitoring of the state quantity and control quantity in the pipe network system.Through the simulation of the existing quality regulation of a thermal power station in the Flowmaster platform and the quality regulation proposed in this paper to change the flow by stages,it is determined that the frequency modulation operation of the water pump in the thermal power station can be divided into five stages according to the characteristics of residential heat use in the community and the change of outdoor temperature,and the hourly secondary temperature supply is set according to the outdoor temperature,which provides theoretical support for the operation in the actual engineering platform.Finally,based on the simulation analysis,the quality regulation operation strategy proposed in this paper is verified in the actual engineering platform of a thermal power station in Beijing.The frequency of the water pump and the secondary supply temperature are set by using the frequency conversion controller of the water pump and the unattended platform of Beijing Thermal Power Station in the thermal power station.The room temperature monitoring equipment of the Internet of Things is used to collect and transmit real-time data in the user’s home,and then use these data for processing and analysis,and then carry out targeted adjustment,so as to enable the heating operation management unit to actively provide heat to the residents’ homes on demand.After the implementation of the operation strategy,by comparing with the data of the same period in previous years,it is found that the heat consumption has decreased by5.68% year on year and the power consumption has decreased by 22.54% year on year,and the user satisfaction has been effectively improved through investigation.