Maximizing Energy Savings with the Systems Approach
30 June 2020
Various countries around the world have taken different approaches towards energy usage and possible energy reduction. Across Europe, the Commission has concentrated on components within the Energy Related Products Directive (ErP).
The ErP focuses heavily on the efficiency of the products and the Commission has already implemented legislation to ensure that products with low efficiency are gradually phased-out across Europe. A significant step in the right direction for sure, although new ‘energy efficient’ components may still be required to operate within an inefficient system, impacting hugely on any possible efficiency gains.
A pumping system is defined as one or more pumps and those interacting or interrelating elements that together accomplish the desired task of moving a liquid. Using the ‘systems approach’ involves comparing the need or demand to the supply.
A system approach starts with defining the ’ultimate goal’ of the system. This includes determining the flow rates that the system must be able to deliver, whether there are flow variations and what kind of control is necessary. These requirements will influence the choice of piping size, control methods, pump size, motor size and so on.
To determine the efficiency of a system, the minimum energy to fulfill the process demand is compared to the actual energy used.
Finally, you take a complete system view and include the losses in the recirculation line as well as the losses in the regulating valve on the line to the second tank. What might have looked like a reasonably good system when measuring the components in the purple square can be viewed as an extremely low efficiency system when looked at using the systems approach.
To do this you need to define the system demand, i.e. the minimum pressure, flow rate and subsequent energy for the pumping system to work. To understand the knowledge and tools required to assess the system, industry spent many years developing the international standard ISO 14414 – Pump System Energy Assessment.
Courtesy of Europump.