Screening Pumping Systems for Energy Savings Opportunities

Abstract

In most industrial settings, energy consumed by pumping systems is responsible for a major part of the overall electricity bill. In some cases, the energy is used quite efficiently; in others, it is not. Facility operators may be very familiar with pumping system equipment controllability, reliability, and availability, but only marginally aware of system efficiency. But there are some good reasons to increase that awareness: 1) As budgets shrink and the intensity of both domestic and international competition increases, the pressure to find additional ways of reducing costs will grow. 2) The reliability of pumps correlates with pump efficiency; that is, pumps operated near the design, or best efficiency point, will tend to perform more reliably and with greater availability. 3) The questions of whether global warming is truly occurring, and if it is, whether humankind's activities play a significant role may both be debatable. But there is no debating the fact that there are finite energy resources, particularly of the fossil fuel variety, on the earth. If we are to be counted as good stewards, then careful, if not frugal resource use is important. The cost of energy consumed by pumps usually dominates the pump life cycle cost. But many end users, already stretched to support day-to-day facility operations, lack the time and resources to perform a methodical engineering study of, in some cases, hundreds of pumps within their facilities to understand the energy costs and the potential opportunity for reduction. Under the auspices of the Department of Energy's (DOE) Motor Challenge Program, prescreening guidance documents and a computer program called PSAT (Pumping System Assessment Tool) have been developed to help end users, consultants, and equipment distributors recognize, both qualitatively and quantitatively, pumping system efficiency improvement opportunities. This paper describes the general methodologies employed and shows case study examples of the prescreening and software application.