Can connecting a variable-frequency pump and a constant-frequency pump in parallel save energy?

My idea is that the core principle of variable-frequency energy saving is to minimize the use of \"exit throttling\", which involves high losses. Based on this idea, it is necessary to ensure that the pump outlet valve, which does not vary in frequency, is kept at a large opening or fully open (provided that the pump operates within its stable operating range when it is fully open), and then the desired flow rate and head are achieved primarily by adjusting the frequency of the variable-frequency pump.

It should be one in use and one as a backup; the inverter is used all the time, which of course helps save energy

There is already consensus on using variable frequency technology to save energy and reduce consumption, but it remains unclear whether energy savings will be achieved after parallel operation; answers to this question are also awaited. We also work on reducing energy consumption in pumps, mainly by using super-lubricating coatings to alter the resistance of fluids within the flow channels, thereby achieving energy savings. Centrifugal pumps generally achieve an energy-saving efficiency of over 2%, and this is unrelated to the use of variable frequency technology; energy savings can be achieved whether or not variable frequency is used.

The operation of critical systems requires two or one water pump; changes in the required flow rate, pressure, and head determine whether a variable-frequency water pump is needed. If a variable-frequency pump is used, the outlet flow rate and pressure can be set accordingly.

For two pumps connected in parallel to operate simultaneously, one requirement is that their piping characteristics must be consistent and their performance curves similar; otherwise, they will affect each other!

It should be one in use and one as a backup, right? Normal variable-frequency operation

The prerequisite for energy savings through frequency conversion of centrifugal pumps is that the head of the centrifugal pump at the power frequency is much higher than the head required by the system. By using variable frequency to reduce speed, the head of the pump is significantly decreased, allowing the outlet valve to be kept fully open or at a large opening degree. This prevents energy loss due to throttling at the outlet valve, which would occur if the pump operated at its normal frequency with a high head. Therefore, if a fixed-frequency pump and an inverter-driven pump are used in parallel (both turned on at the same time), energy savings can be achieved if the head required by the system is much lower than the head provided by the pumps. This is done by adjusting the opening degree of the outlet valve for the fixed-frequency pump, and by reducing its operating frequency for the inverter-driven pump. This method is relatively difficult to operate. If the system requires a head similar to that of the pump, energy savings cannot be achieved.