Simulation Analysis On Optimization Ot Terminal On-off Regulation Of Metered Heating System

Since 2009,the research and application of heating terminal on-off regulation technology has been developed rapidly.The heating cities in northern China have carried out pilot studies,followed by a large-scale energy-saving transformation.At present,although the domestic heating system terminal has the condition of intelligent regulation in hardware,it lacks the software foundation to adapt to it,and most of them do not play the role of intelligent regulation effectively.In order to understand the main problems existing in heating terminal regulation,and to explore the method suitable for intelligent regulation of room temperature at the end of heating system,this paper preliminarily analyzed the mechanism and characteristics of heating terminal regulation by combining theoretical analysis with simulation.Firstly,based on the comprehensive analysis of building thermal process and heating terminal dynamic process,the dynamic model of heating system components(room,radiator,on-off valve)is established,and the system model is validated under steady-state conditions.Secondly,aiming at the PID control and the fuzzy control algorithm in the room temperature control algorithm,through the Simulink simulation of MATLAB,the response speed,anti-interference ability and the steady-state error of the system after stabilization are compared and analyzed.Finally,the fuzzy control strategy is applied to the multi-condition simulation of the actual heating system,and the room temperature changes and valve on-off characteristics under different user setting modes are obtained.The effects of thermal inertia of the envelope,thermal disturbance of the adjacent room and solar radiation on the terminal regulation response characteristics are further analyzed.Through the above research,the main conclusions are as follows:(1)The simulation model of heating system and building is established in this paper.The steady-state verification is consistent with the theoretical calculation results,which shows that the basic framework of the model is correct.(2)Compared with PID control,the fuzzy control algorithm can effectively improve the dynamic response performance of temperature control system,reduce the impact of external thermal disturbance and building thermal inertia on the lag,and can deal with the stability of time-varying systems.(3)For building rooms with large thermal inertia,the room temperature change rate under the control of heating terminal is 0.1-0.5 C/h,which is much lower than that of air conditioning system at 3 C/h.Therefore,the room temperature adjustment method of air conditioning system should not be transferred to heating system.The maximum change rate of room temperature is about 0.8 C/h after multi-room fuzzy regulation.Compared with the single room terminal fuzzy regulation,the response speed has been significantly improved,which indicates that the adjacent room thermal disturbance is a non-negligible disturbance factor to room temperature regulation.Under the effect of solar radiation,the room temperature of the south-facing room will increase dramatically by 4 C/h.and the room temperature will exceed the set room temperature for a long time by 1.5-2 C.The work-rest adjustment mode is more suitable for buildings with smaller thermal inertia index of the enclosure structure.