Feb. 6, 2002 -- By designing a system that substituted a smaller pump, ITT Industries' Flygt unit helped save the City of Milford, Connecticut, more than 20% of the annual energy costs at one sewage lift station - helping to meet the U.S. Department of Energy's Motor Challenge Program.
ITT Industries director of technology, Gunnar Hovstadius and Art Berube, collection systems foreman for the City of Milford, Connecticut, stand 4 stories underground with Flygt's energy efficient pump.
ITT Flygt's Solution
In order to maximize pumping efficiency, Flygt recommended more closely tailoring the pumps to the system's true needs. "Our approach was to replace one of the system's four identical large pumps with one smaller model", said Hovstadius.
The idea being that the smaller Flygt pump could more efficiently handle typical system inflows, and the larger pumps could be reserved only for peak flows. While the smaller pump needed to run longer to handle the same total volume, its slower pace and reduced pressure would result in less friction-related losses.
With the smaller pump serving as the lead pump, measurements were taken over several weeks in the same manner as they were for the base case. And when the verdict came in, Flygt was right on the money. As it turned out, the smaller pump could more effectively handle inflows about 90 percent of the year, and using it as the lead pump produced significant savings.
As verified by a DOE-sponsored Independent Performance Validation team, the savings achieved by substituting the smaller pump is projected at 36,096 kW - or more than 20% of the system's annual electrical energy consumption.
Translating the same system philosophy to the city's 36 other treatment centers would result in a savings upwards of USD 100,000 annually.
In addition to the direct energy cost savings achieved, ITT Flygt's "stepped" approach eases wear-and-tear on the system, and is anticipated to require lower maintenance and less downtime, and to lengthen the life of operating equipment and electrical switch gear. As an added bonus, the station noise level is significantly reduced when the smaller pump operates.
Art Berube, the system's foreman, said he is "truly amazed with the savings and especially pleased with savings in maintenance." Furthering the Motor Challenge mission, Flygt has been taking the message on the road, sharing its systems expertise in seminars arranged by DOE is arranging to explore energy-efficient pumping solutions with various groups around the world.
A Look At The City Of Milford
During 1996, Flygt worked with the DOE to set up a showcase demonstration at the Welches Point Pump Station, a medium-sized water treatment plant located in the city of Milford, Connecticut.
The station's current system included two identical large-size pumps. Either one of the pumps was capable of handling the station's maximum normal inflows. Two would be needed in extreme flooding conditions. A third pump was on-site as a back up. The pumps, which reside about 40-feet below ground level, are driven by floor mounted motors located above ground in a single story pump house.
As the demonstration got underway, Hovstadius and his team worked closely with the city of Milford to uncover ways they could advance the Motor Challenge goals and save the city money. The first stage of the demonstration involved the careful measurement of the existing pump's performance to verify its actual operating point (flow rate and head). A recording device was installed on-site to record the pump cycle over several weeks.
This enabled the demonstration team to calculate the total pumping volume and the average operating rate flow for each pump. They then projected the system's annual energy consumption for comparison with the optimized case proposed by Flygt.
The U.S. Department of Energy's Motor Challenge Program unites business and government in a quest to capture 25 billion kilowatt-hours-per-year of electricity savings by the year 2000.
Since a staggering amount of all industrial power -- more than 79 .percent is consumed by motors, a specific goal of the program is to increase the use of energy efficient electric motor driven systems.
The Energy Policy Act of 1992 (EPACT), which took effect in October 1997, requires that most general purpose motors manufactured for sale in the U.S. meet minimum efficiency standards. Utilizing these more efficient motors will put companies on the path toward greater efficiency, but meeting the Motor Challenge goal requires more than installing efficient motors... it requires maximizing the efficiency of motor driven systems.
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