(1) Determine the number of main pumps according to the proportional relationship between the flow range in the high efficiency area of variable frequency pump and the design flow variation range. Because there are many users in high-rise buildings and the load of water supply system is heavy, generally 2 ~ 4 main pumps (no more than 4) should be set up, and a standby pump with water supply capacity equal to the largest one should be set up. Within the range of design flow change, each main pump should work in the high efficiency area.
(2) At the rated speed, the working point of the water pump should be at the end of the right side of the high-efficiency section. The speed regulation range of water pump is between 0.7 ~ 1.0. Generally, a speed regulating pump with other constant speed pumps can be used for water supply. When the pipe network flow changes greatly or the pressure fluctuation required by users is small, the scheme of multiple speed regulating pumps can also be adopted.
(3) At present, frequency conversion and constant pressure water supply for high-rise buildings adopts constant pressure and variable flow water supply mode. When conditions permit, the control point can be set at the most unfavorable water distribution point or the outlet of the pump, and the water supply mode with variable pressure and variable flow can be used for operation. Constant pressure water supply should use the same type of main pump, and variable pressure water supply can use different types of main pumps.
(4) The water supply pressure of each partition of the high-rise building should meet the water pressure required by the most unfavorable water distribution point in this area in the design.
(5) Due to the higher floors of high-rise buildings and more users, the requirements for water quality, safety and reliability are more stringent. Therefore, when using variable frequency speed regulating water supply equipment, there should be double power supply or double loop power supply, and the motor should have protection functions such as overload, short circuit, overvoltage, lack of phase, undervoltage and overheating. The working point of the pump should be close to the highest efficiency point of the pump characteristic curve.
(6) Variable frequency constant pressure water supply has two layout forms: upward water supply and downward water supply. In practical engineering design, most of them adopt the form of upward pipeline.