Study On The Terminal Dynamic Form Of Distributed Heating System

With the continuous improvement of our living standards and the rapid development of the construction industry,the application of central heating system is more and more widely,but it causes the increment of energy consuming,and the energy structure of our country is facing severe challenges.In order to solve the problems of the poor heating effect,uneven,energy waste in traditional heating system,this paper proposes a distributed heating system has been recognized by many experts and scholars,the distributed heating system has many advantages compared with the traditional heating system,such as high stability,high adaptability of thermal hydraulic load change,high transport efficiency and so on,it has different system forms because of its different terminal dynamic forms,terminal power supply and heat distribution according to need is a key technology to ensure the safe and reliable operation of distributed heating system.First,this paper compares distributed heating system with the traditional heating system from the aspects of system structure and energy saving effect,analyses the advantages of distributed heating system,and then proposes three terminal dynamic forms of distributed heating system: variable frequency pump,mixing pump and injector,proposes the terminal dynamic forms is a key factor to ensure the operation of the distributed heating system.Secondly,the working principle and energy saving effect of three kinds of terminal dynamic forms are analyzed in detail:variable frequency pump changes the motor speed by changing the power frequency,so as to reached the energy saving effect by controlling the size of water,take Ji’nan city’s heating pipe network as an example,we can calculate that it has obvious energy saving effect by using the variable frequency pump as terminal dynamic form compared with the traditional heating form;this paper takes four-way water mixer as an example,simulates its distribution of the internal temperature field by CFD software,four-waywater mixer has regulating action on two network’s supply water temperature,and concludes that mixing pump has low energy consumption and energy-saving effect as a terminal dynamic form compared with plate heat exchanger through an application case;this paper studies the structural design of the jet pump,simulates its distribution of the internal temperature field,velocity field and pressure field by CFD,and concludes that jet pump not only saves energy but also reduces the initial investment as a terminal dynamic form through an application case,it has great advantages in the heating system.Finally,this paper analyzes the application of three kinds of terminal dynamic forms:variable frequency pump in a wider scope,especially suitable for the heating system of long distance,multiple users and large flow;mixing pump is suitable for the direct system of supply water temperature exceeds the user required temperature,such as both existing radiator heating system and floor radiant heating system,mixing pump is installed at the entrance of floor radiant heating system;jet pump is suitable for the system of high and low area pipe network system,and is also suitable for the system of radiator heating and floor heating with the precondition of sufficient water pressure difference.