Using Specific Energy to Determine Energy Consumption for a Pump

In order to determine energy consumption for a pump it is possible to use the key number Specific energy, Es:

If we then calculate the specific energy it becomes:
Large pump: Es= 28/0,7 = 40k kWh/m3
Small pump: Es = 10/ 0,5 = 20k kWh/m3
As we see in the formula not only the efficiency of a pump determines the energy consumption but also the total head. The magnitude of the head depends of course of the behavior of the system curve (geodetic head and how steep it is).Therefore we see that the characteristics of the pipe system always have to be included when doing these types of energy analysis.