空调变流量水系统的设置方案及运行工况分析

通过分析一个实际工程的机组负荷报告，说明采用变流量系统的必要性，对变流量系统及其节能原理进行了介绍。根据管道水力特性曲线与水泵的性能曲线，运用理论分析的方法，对影响末端定压差控制方式的因素和该控制方案的利弊进行了分析。利用特性曲线对变速泵与定速泵并联运行工况进行了讨论，指出其正确切换步骤。得出结论：压差设定值越大，该控制方案节能效果越不显著；基于阀门开度和变压差设定值的改进方案具有显著的节能效果；变速泵与定速泵并联比定速泵之间的并联节能效果显著。

Analysis of setting plan and running condition in variable water flow system

The necessity of applying variable water flow systems is analyzed. Variable water flow systems and their theory of energy-saving are recommended. Factors affecting constant pressure difference control method and advantages and disadvantages of the control plan are analyzed theoretically through pipe system head curve and pump performance curve. Running conditions of parallel-connected variable and constant speed pump are discussed using pump performance curve, and the correct switch steps are pointed out. Conclusions are drawn that the more the value of the constant pressure difference is, the less the effects of the control plan are, and vice versa; and that the improved plan based on valve lift and variable pressure difference has sensible effects of energy-saving; and that the energy-saving effect of parallel-connected variable and constant speed pumps is more sensible than that of constant speed pumps.