Optimal design of pipe diameters for distribution pipe networks of district cooling and heating systems

Establishes an optimization model of the pipe diameter of the district cooling and heating system with the annual value of the life cycle cost of the entire pipe network as the objective function. Proposes a method to comprehensively optimize the pipe diameters of the most unfavorable loop and other branch loops. Develops an optimized design program and uses the program to optimize the design of an engineering example. Compared with the traditional economic specific friction method, the annual equivalent cost of whole life cycle is saved by 7.38%. The results show that the optimization method can better balance the initial investment and operation cost of the pipe network, improve the economy of the pipe network, with better social and economic benefits and design guidance significance.