区域供冷系统枝状冷水输送管网的优化设计

Optimal design for tree-shaped chilled water pipe network in district cooling systems

在各并联管路压力损失相等的条件下建立了优化设计模型,其目标函数为系统的年度费用,由冷水泵的年运行费用、冷水泵的折旧费用、管道的折旧和维修费用及输水管道冷量损失费用组成。通过实例计算,得到以下结论:区域供冷系统冷水管路的设计不能按传统的等比摩阻或等流速设计思想进行;采用优化模型比等流速设计年度总费用约减少17%,具有明显的经济效益;若采用等流速设计,各节点的压降偏差较大,会增加运行调节的困难,容易产生水力失稳,既不利于系统的稳定运行,又增大了运行费用。

Develops an optimal design model on condition that the pressure drops of each parallel connection loop are equal. The objective function of the model is the annual costs of the system, including annual operating costs and depreciation costs of chilled water pumps, depreciation and maintenance costs of pipeline, and costs of chiller power consumption rising from cold loss through chilled water pipe wall. By a case study, obtains the following results： the tree-shaped chilled water pipe network in district cooling systems should not be designed by equal specific frictional resistance or by equal velocity; the annual costs of the system obtained by the optimal model decrease by 17% than those by the equal velocity model and the economical benefit is remarkable; the differences of pressure drop of each segment pipeline are considerable by the equal velocity model, then the adjustment of the system is difficult and the pressure stabilization is destroyed easily, and the annual costs of the system increases.