Identifying Energy Savings Opportunities in Industrial Pumping Systems

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. There are some good reasons to increase that awareness: As budgets shrink and the intensity of both domestic and international competition increases, the pressure to find additional methods to reduce operating costs will grow. The reliability of pumps correlates with their efficiency; that is, pumps operated near their design, or best efficiency point, will tend to perform more reliably and with greater availability. More frugal and efficient use of the earth's limited natural resources is essential. The cost of energy consumed by pumps usually dominates the pump life cycle cost. Many end users, already strained to support day-to-day facility operations, lack the time and resources to perform a methodical engineering study of the many pumps within their facilities to understand their associated energy costs and the potential opportunities for energy savings. Under the auspices of the United States Department of Energy's (USDOE) Motor Challenge Program, screening guidance documents and computer software have been developed to help end users, consultants, and equipment distributors recognize, both qualitatively and quantitatively, pumping system efficiency improvement opportunities. A key element in the Motor Challenge optimization strategy is to encourage a systems approach to how motors, drives, and motor-driven equipment are engineered, specified, operated, and maintained by industry. Because pumps have been identified as the single largest end use application, accounting for 25% of motor systems energy use in all manufacturing industries in the United States, they are a natural target in any effort to improve motor-driven systems' energy consumption. The general thesis of this approach is that it is more important to gain a measure of the overall system efficiency or effectiveness than to focus on individual components. The elements that comprise the systems approach and their general order of review (in reverse sequence) are: ultimate system goal or purpose piping system, pump, gear or coupling, motor, adjustable speed drive (if applicable), motor starter, transformer. This paper describes the general methodologies employed and shows a case study example of the screening and software application.