Abstract：The energy consumptions of constant-pressure water supply and variable-pressure water supply are studied.The energy consumptions of constant-pressure and variable-pressure running with pump′s full-speed are compared with diagram.The static head change of network characteristics with pump′s running condition is analyzed.Based on a pump station′s running data,the running diagram,the relation of pump efficiency,flow under variable speed,the relation of energy consumption per 100 m~3 and rotating speed are obtained.It is found that constant-pressure water supply has the smaller variable ranges of rotating speed and flow rate,the energy consumption at small flow rate increases,and the variable-pressure water supply has the larger variable ranges of rotating speed and flow rate.The advantages and disadvantages of pump constant-pressure and variable-pressure water supply are compared from three aspects of variable-speed range,pump′s high-efficiency field and energy consumption.The conclusion is obtained that the energy consumption of pump variable-pressure water supply is 20% lower than that of pump constant-pressure water supply.
