And decided pump flow and pressure of maximum design load (load rate 100%) compared, a years in the load rate in 50% following of run time nearly half, General frozen water design temperature for 5~7?, and actually in annual summary most time frozen water of temperature only for 2~4?, that pump is is full power run, increased has pipeline energy loss, waste has pump run of conveying energy. Invalid use of this energy, and variable frequency speed control technology can automatically regulate the flow and energy-saving effect.