There is potential for savings just about everywhere, because all planning and dimensioning are done so that pumps are over-dimensioned, to be sure that they work in extreme conditions. This means that they cannot be driven at ideal efficiency which in turn leads to lost energy. With variable speed drive (VSD) control even over-dimensioned machines can be driven more efficiently.
When pumps are operated in parallel and their control is based on VSDs, there is a potential for energy savings of up to 60 per cent. The biggest savings can be achieved in environments where fluctuations of the flow are remarkable. These findings come from a study done at the department of Energy and Environment at the Lappeenranta University of Technology (LUT) in Finland.
ABB has developed an intelligent package of control software for VSD. Using this software, which is available for ABB's industrial drives, interconnected VSDs can ensure the optimal pump operating arrangement in terms of pump efficiency at any operating point, without using an external programmable logic controller (PLC).
This paper describes the technical back round, simulations and test results when optimization was fully utilized.