Reduction of Energy Consumption through Pump Efficiency Analysis

Riley Dodds


Water scarcity, global warming, lack of fossil fuels, and future Green Act goals and legislature are at the forefront of the policy change and election discussion within the United States. As civil engineers, these topics are heavily discussed and challenged within the field and new solutions along with innovations are in constant demand. Within the community of Akron, the Akron Water Supply Water Plant continues to actively innovate and solve numerous concerns ranging from the quality of water to the overall operating costs. Energy consumption cost Akron Water Supply over $952,914.32 and 14,411,960 of kilowatts per hour of electrical energy to perform all necessary functions in 2012. Present day, the costs per kilowatt per hour of electrical energy continues to increase. Decreasing overall energy costs while maintaining pump efficiency is vital for the community as well as Akron Water Supply. Since the addition of the variable frequency drives direct impacts in cost as well as kilowattage can be seen, however, pump degradation is still prominent and could reverse a decade of efforts to lower energy consumption. The objective of the report is to analyze the current operating conditions of Akron Water Supply and create predicted pump curves to depict degradation over the past 10 and 50 years. Degradation due to age affects pump curves and pump efficiency in a non-linear pattern and requires mathematical calculations to accurately produce realistic pump curves. Projections of pump curves based off present-day operations demonstrated immense degradation of 8% in impeller size for the 700- horsepower pump and 12% in impeller size for the 1250-horsepower pump. Consistent with pump affinity laws, the horsepower for both the 700 and 1250 HP pumps also demonstrated great jumps in performance. Analysis of two weeks of pump operations also demonstrated that the current pumping operations are below the projected system curves created in 2012. These visual displays of degradation of the pumps will aid in the discussion of the final solutions for Akron Water Supply as forwarding progress to more energy-efficient plants continue.