The Research On Operation Optimization Of Distributed And Mixted Water Heating System

With the rapid development of economy and science and technology,more and more emerging technologies and intelligent equipment have been put into the field of central heating,which makes the quality of central heating and energy efficiency and other aspects have been greatly improved.However,compared with some developed countries,China's central heating system still has a certain gap in the use of energy and control means.Firstly,the optimization scheme of the key parameters of the distributed mixed water system is proposed.Through the establishment of hydraulic and thermal simulation model of heating system to simulate the dynamic process of the system,and put forward the method of system operation adjustment.In order to solve the problem of excessive power consumption of equipment in heat exchange station,the paper puts forward the transformation scheme of distributed frequency conversion pump,and makes a comparative analysis on the power consumption of pump in theory and traditional heating system.The main research contents and work done in this paper are as follows:First of all,based on the engineering applicability of frequency conversion pump,this paper studies the influence of the location of the zero pressure differential and the characteristics of the pump on the hydraulic working condition of the heating system when the distributed mixed water heating system is renovated and expanded.In this paper,water pump samples from two manufacturers are selected to conduct quantitative analysis on two different types of pumps,namely the flat type and the steep type.In order to maximize the working performance of the variable-frequency pump,a new method of pump selection is proposed to select the pressurized variable-frequency pump with stronger adaptability.The control variable method is used to analyze the influence of the zero pressure differential of the system and the access point of the newly added heat load on the hydraulic condition of the distributed mixed water heating system,and to optimize the design parameters of the system.Secondly,based on the relationship between energy transfer and conservation,the transfer model of each part from heat source to heat user is built,and the simulation program of heating system operation is built by using Simulink module in Matlab.The simulation simulates the dynamic change process of indoor temperature of hot users and water supply temperature of secondary network when outdoor temperature and outdoor temperature change,and puts forward the corresponding temperature-pressure nested heating quantity control strategy.And then,on the basis of the classical PID control,the transfer model based on heating system,using fuzzy logic tool module to control the parameters of the Simulink simulation research,the design is suitable for the nonlinear characteristics of the central heating system fuzzy-PID controller,and analysis and design of fuzzy controller and traditional PID is builds the dynamic model of the use effect.The results show that compared with the classical PID control method,the fuzzy PID controller has the characteristics of smaller overshoot and shorter adjustment time for the control process of temperature and pressure parameters with obvious hysteresis,which makes the whole control system more stable.Finally,the economic mathematical model of distributed mixed water heating system is established.Based on the theory of pump selection and system operation optimization proposed in this paper,the economic applicability of the reform plan of distributed mixed water heating system designed in this paper is analyzed by taking an actual reform project as a case.The results show that compared with the original heating system,the improved distributed mixed water heating system has a good hydraulic condition,and the energy saving effect is especially remarkable.