[Equest-users] PUMP-KW and motor efficiency

[Bishop, Bill]

A value entered for PUMP-KW should include the losses for motor efficiency, correct?

The help menu for PUMP-KW describes this as "The design power consumption of the pump. If entered, its value should be consistent with the values for the pump's head, flow, impeller efficiency and motor efficiency. If not consistent, the program will recalculate the impeller efficiency to force consistency."
I notice that if I leave pump HEAD and FLOW blank (as I often do) and enter values for PUMP-KW and MOTOR-EFF, that changing only the motor efficiency changes the reported pump (and model) energy, and also changes the calculated head and flow. The fact that the head and flow change confirms for me that PUMP-KW includes motor losses AND that we still need to enter the correct motor efficiency (and not "1").

I also just noticed that when you view pumps in spreadsheet view, you can access VFD-LOSS which adds 5% power by default when you select "CAP-CTRL = VAR-SPEED-PUMP". These losses impact the KWH and peak KW reported in PS-H for the pump. I think it is reasonable to leave these default losses in an Appendix G. baseline model when VSDs are required per G3.1.3.5 and/or G3.1.3.10.

Thanks,
Bill

[Senior Energy Engineer 28Jun2012]<mailto:wbishop at pathfinder-ea.com>

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