Optimal Design And Study For Pipeline Diameter Of Outdoor District Heating System

With the enlargement of the urban construction scale and the increasing heat users. The urban central heating instruction has attached more importance to the optimization of the heating pipe network. Urban central heating pipe network optimization research, can not only achieve a goal that saving investment cost, reducing heating energy consumption, improving the efficiency of the enterprise, but also is the important guarantee to realize the security and reliability of heating. Therefore, the optimization of urban central heating pipe network has important social significance, and is the research topic of urban heating industry that needs to solve. The optimization of heating pipe network mainly includes three aspects: one is the layout optimization of pipeline network, the second is the optimal design of the pipe diameter, the third is the operation optimization of the network. And the core issue of the pipe network optimization is the pipe diameter optimization design, because it directly affects the initial investment and operation cost of the heating system. The nature of the pipe diameter optimization design is: in case of the stress conditions and certain reliability are all meet, finding a set of optimal pipe diameter combination, making the infrastructure investment cost and operation cost minimum in the whole pipe network system.This article studied the pipe diameter optimization in view of the directly buried heating system in city. Firstly, the research status domestic and foreign of pipe diameter optimization about central heating pipe network is summarized. And then preparing for the optimal method about the mathematical model through analyzing and comparing several kinds of pipe diameter optimal methods. Secondly, establishing the mathematical model about the heating pipe diameter optimization, and in order to make the optimization goal more in line with the actual situation, the model mainly considered the infrastructure investment cost and operation cost. Thirdly, writing the constraint conditions of the optimization mathematical model, they mainly include node flow continuity constraint, pressure constraint, users, node head demand constraint, the pipe velocity constraint. Fourthly, applying the selected method to solve the model, and checking through the instance, verified the reliability and energy saving. Finally programming software to calculate the cost of central heating pipe network using C#, the software implements the pipe diameter optimization and cost comparison that original algorithm with the energy saving algorithm, achieving the purpose of energy conservation and cost reducing. And electricity as the sensitivity factors, analyzed their influence on optimization results by using the single factor analysis method.Finally, based on the cost computing of district heat supply network, the software is made by using Matlab and c # hybrid programming, which is friendly, easy operating, convenient. The software is the basis of simulation analysis carried out on the hydraulic condition, which realized the optimization of pipe diameter, the life cycle of the original algorithm and energy saving the cost of computing, optimization algorithm of the saving rate.The software achieved the purpose of energy conservation and money-saving. At the same time, the correctness of the software is validated by examples.