Staging pumps through Wire-to-Water Efficiency (WWE) optimizes pump package performance. An optimized pump package maintains load requirements, achieves efficient operation, and saves money.
What is Wire-to-Water Efficiency?
Wire-to-Water is a ratio between the electrical energy input to the pumps and the kinetic energy achieved by this input. Wire-to-Water Efficiency, developed by Systecon in 1984, helps determine pump selection and sequencing for optimal pumping system performance. WWE can reduce operational costs while supporting load requirements for a pump package.
To calculate the WWE, the system flow from the system flow meter, system head from the system differential pressure transmitter, and system kW from the system wattmeter are measured. This value is modeled during pump and system selection to assist engineers and owners in choosing the best-fitting option for their project needs.
How WWE Is Used
The WWE Report (below) shows that operating pumps at their most efficient flow results in optimized performance.
During Systecon’s Performance Testing of the actual pump package, the report data helps to confirm sequencing, system operation, and efficiency since there may be slight differences between the theoretical report and the real-life pumping system. With over 30 years of developing Wire-to-Water, Systecon’s models have become very accurate. Once up and running, Systecon’s system controls will continuously update the WWE from actual load data.
Optimizing Pump System Performance
Although operating pumps at their most efficient flow rates results in optimized system performance, it is not always obvious which sequences will produce these results. Using Wire-to-Water Efficiency in a multiple pump, variable speed system allows the system to operate at its most efficient point, which results in proper system flows, reduced energy usage, and reduced wear on pumps.
Simpler systems may run one pump up to a pre-determined capacity, then bring additional pumps online as necessary. While this may be the easiest way to control the system, it’s not the most efficient. In the real-life application example below, running one pump to near full capacity will result in over 20% efficiency loss compared to two pumps maintaining the same flow conditions. The system is also less efficient, with one pump running at 1421 GPM rather than using two pumps to maintain this flow rate. Wire-to-Water efficiency helps determine the exact point at which the system should change pump operation to prevent wasting energy.
