Choosing the right motor control system is crucial when you are building an energy-efficient pumping system. The EPA or Extended Product Approach will help. Read on to find out more.
Introducing EPA. Extended Product Approach.
EPA came into being as a response to the European Commission’s 2009 Ecodesign Directive on Energy using Products, which stipulates that manufacturers of energy-consuming products are required to reduce the energy consumption of products at the point when they design them. Put simply, it is an approach where when considering the efficiency of a new installation, designers consider how to build the overall system to select the most efficient combination of products overall.
Figure 1 below illustrates a typical extended product or systems-based approach for a pumping installation
Variable Speed Drive OR D.O.L plus Valve?
VSD’s or Variable Speed Drives control the flow rate in variable flow applications and allow the pump to be operated at its Best Efficiency Point (BEP), and they help to avoid the energy loss that results from using a throttling valve. But although VSDs offer an energy-efficient solution for variable flow applications, designers should think about how they compare to Direct-On-Line starters.
In constant flow applications, for example, a Direct-On-Line starter with a correctly sized Premium Efficiency motor (IE3) results in the most energy-efficient solution. Energy loss is reduced during the pump’s nominal operation and no consumption by the motor starter during the stand-by phase.
Figure 2 below shows a graphical comparison of the two systems.
Applying EPA to a Pumping System – Key Steps
What is fundamental when taking an Extended Product Approach is that the selection of the motor control system needs to be based on how well the full Extended Product meets the application’s requirements and duty profile.
When designing a pumping system, engineers should follow the 3 steps illustrated in Figure 3 below.
In summary, start by confirming whether the flow of your pumping installation is constant or variable. If your installation requires constant flow, check if water hammer will be something you need to address. You can then choose between Direct-On-Line starter, Star-Delta starter, Soft starter or Variable Speed Drive. This will allow you to start building your pumping system with the appropriate motor control solution and avoid issues caused by over-sizing.
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