Dynamic Properties And Optimal Control Strategies For District Heating System Based On MATLAB/Simulink

District Heating System(DHS)are widely utilized for space heating in residential、commercial and industrial buildings, and has become the main type of centralized heatingsystem. Recently with the rapid development of automatic control technology, the regulationtechniques for DHS are continuously strengthening. The research on whole dynamicproperties of DHS has become the focal point. Although domestic and overseas scholars havedone much work in dynamic properties of DHS, the objects of study are one or several partsof DHS and lack of a complete model for DHS dynamic properties researching. Therefore, itis significant and necessary to establish a complete DHS simulation model for the research ondynamic properties.Based on quality and energy balance equations, starting from central regulation, thedynamic mathematical model for all important parts of DHS are established by using thespecific heat particle method. The dynamic simulation software “District Heating SystemSimulation Library” is completed by using MATLAB/Simulink. In the library all functionmodules can be found and everyone can use them in MATLAB/Simulink. The applicationarea of the software is introduced, which includes steady-state and dynamic propertiesresearching of DHS, DHS regulation, aided DHS design, research on control strategy of DHS.Through research and analyze the temperature response from simulation under designcondition and effect from a variety of disturbances, quantify the effects from all kinds offactors to temperature response, so that designers and operators have an intuitiveunderstanding to system’s steady-state and dynamic properties. A new way which plotregulating curve by simulating for the actual working condition is brought. Above all theoperation will be more reasonable.Using optimal regulating curve simulate traditional open-loop and automatic closed-loopcontrol strategy for DHS. During open-loop control strategy simulation, do much research ontime interval of regulation. When the time interval of regulation is3~6hour, the fluctuation ofindoor temperature is18±1.5℃. Using fuzzy PID controller with parameter self-adjustmentin closed-loop control strategy simulation and compared the temperature response withopen-loop control strategy simulation. The fluctuation of indoor temperature is18±1℃. The control effect is obvious.