Pump Energy Index (PEI) is a value representing a pump’s efficiency as compared to the minimum efficiency defined by the Department of Energy (DOE).
Basic Model is the tested pump as specified by the DOE, and provides a PEI value for a defined group of individual models. These groups can include variable trims or stages but must be of the same pump type configuration. An example of a basic model would be a CR10-3-2P-PM tested at 3-stages, with a 3,600 rpm and 5 hp motor.
Individual Model is your pump’s model, as designated on the nameplate, and represents the actual configuration of the pump. The PEI value on an individual model’s nameplate comes from its basic model. For example, an individual model’s for our basic model example could include: CR10-1-A-F-A-G (1-stage, 3 hp, 2 pole motor), CR10-3-A-F-A-G (3-stage, 5 hp, 2 pole motor), or CR10-5-A-F-A-G (5-stage, 10 hp, 2 pole motor).
There are separate calculations for PEI depending on your load type:
Constant Load Curve (PEICL)
Weighted average for constant load is taken at 75%, 100% and 110% of best efficiency point (BEP) flow rate
Variable Load Curve (PEIVL)
Weighted average for variable load is taken at 25%, 50%, 75% and 100% of BEP flow rate
To get a rough idea of what your pump’s PEI rating might be, try the Hydraulic Institute’s Calculator.