I. How to use This Page
At line 1 – choose the power source and if an electric-powered pump, indicate if it is a submersible motor or not.
At line 2 – indicate whether it is a water well or not. If it is a pumping plant either use the pull down to choose a Specific Capacity or enter it directly in the rose-colored box. (Specific Capacity is the gallons per minute supplied by the well per foot of drawdown.)
At line 3 – enter the horsepower of the engine or motor.
At line 4/5 – enter either the acre-feet pumped each year or the annual hours of operation
At line 6 – enter your average cost of energy
At line 8 – enter the current Overall Pumping Plant Efficiency in percent
At line 9 – enter the current pump flow in gallons per minute
At line 10 – enter the current Discharge Pressure in pounds per square inch
At line 11 – enter the current pumping water level in feet. Do not enter a zero.
At line 12 – if you have an idea of any other pressure losses in the pumping system enter them here in feet of water head.
Press the Calculate button
Certain assumptions will be made regarding the After Retrofit conditions. Examine these closely, especially the pump flow and discharge pressure. You can directly enter the Assumed After Retrofit OPE, Flow, Discharge Pressure, Pumping Water Level, and Other losses and press Calculate Button so that it will recalculate everything according to the assumptions that you have entered.
Note that it is always assumed that the same amount of water will be pumped before and after the retrofit.
Pressing the Reset button will “zero” all entries.
The following is a description of the automated assumptions for pump performance after the retrofit. As noted above you can override any of these.
OPE – This is assumed based on the nameplate horsepower of the pump and whether it is a submersible motor or not. After project OPE for a natural gas-powered pump will always be assumed to be 25%.
Flow – if the discharge pressure is 10 psi or lower than the after-retrofit flow is assumed to be 30% higher than current. If the discharge pressure is higher than 10 psi the after-retrofit flow is assumed to be 15% higher. This is modified further depending on how high the current OPE is – the higher the current OPE, the lower the assumed increase in flow will be.
Pumping water level – if a water well the PWL will be modified based on the increase in flow and the Specific Capacity of the well.
Discharge Pressure – if a water well the DP will be assumed to be the same before and after the project. Otherwise it will increase based on the following equation:
[DPAfter] = (([FLOWAfter] / [FLOWNow]) * ([DischargePressure] ^ 0.5)) ^ 2