The Extended Product Approach (EPA) methodology
When it comes to build an energy efficient pumping system, the choice of the appropriate motor control system is crucial. As a response to the European Commission’s regulation on Energy using Products, the EN 50598 series proposes a system-level approach called the Extended Product Approach, to select the most efficient combination of products overall.
When designing energy-efficient pumping systems, the use of the Variable Speed Drive (VSD) to control the flow rate in variable flow applications allows to operate the pump at its Best Efficiency Point (BEP) and to avoid the energy loss associated to a throttling valve. Although a VSD is often an energy efficient solution for variable flow applications, it should not become an automatic reflex.
For example, in constant flow applications the use of Direct-On-Line starter with a properly sized Premium Efficiency motors (IE3) leads to the most energy efficient solution. With such a system, there is less loss during the nominal operation of the pump and no consumption of the motor starter during the stand-by phase.
The essential idea is that the choice of the motor control system shall be based on how well the resulting Extended Product matches the requirements and duty profile of the application.
How to apply the EPA to pumping system?
Looking at pumping systems, the system-level analysis is a 3 step process:
The first step is to identify the nature of the flow of your pumping installation (either constant or variable). Secondly, if you are dealing with constant flow situation you must determine if water hammer will be an issue. Now you are in position to choose between Direct-On-Line starter, Star-Delta starter, Soft starter or Variable Speed Drive. Finally, you can start to build your pumping system with the appropriate motor control solution and avoid over-sizing
As a result, the Extended Product Approach allows you to optimize the choice of the motor control system in order to ensure a high energy efficiency level for your pumping system.
For details, case studies, and further discussion, you can read the Control Panel Technical Guide on this topic «How to select the appropriate motor control system for your pump?», or leave a comment below.