When the water demand reaches its peak, the Small Household Submersible Pump system will run at full power, but they will only be partially loaded at other times of the day. Although valves can be used to control the flow of the pump, doing so will waste energy:
The control valve at the pump outlet will reduce the flow due to throttling, resulting in a pressure drop. However, the hydraulic loss at the valve represents wasted pumping power, and if the pump is often operated under partial load, the cumulative cost may be significant.
Another control method is to use a recirculation valve, which redirects excess flow back to the pump inlet. This control method wastes more energy than the control valve at the pump outlet and requires additional piping.
Adjusting the speed of the pump is a more effective way to control water flow, because the absence of a control valve will cause hydraulic loss. The variable frequency drive can reduce the speed of the pump motor until the provided flow meets the demand. When the pumping system is subjected to variable workloads, the potential savings will increase, which is the case with pipeline installations.
The scope of application of pump control goes beyond drinking water systems. By controlling the pumps of hydraulic HVAC equipment, you can also save a lot of money. When the building is not full and the output power of the heating and cooling system is reduced, the pump that provides cold and hot water to the fan coil can also be reduced in power.