But from an energy saving point of

But from an energy saving point of view, constant pressure and variable speed can reduce some of the wasted energy, but this is not the best way. As shown in figure 4-2, A1 is the working point of the pump under the control of constant pressure variable. The corresponding flow, lift and speed are Q1, H2 and N0, respectively. If the constant pressure variable water supply is adopted, when the system water consumption changes and the pipe network flow changes from the maximum Q1 to the minimum Q2, the working point of the pump will also change to A2 and the rotating speed will also change. To the N1. As can be seen from figure 4-2, in fact, the constant pressure variable water supply is achieved by using both variable-speed and throttling adjustments, so the characteristics of the pump and pipeline change accordingly