Best Practicefor Energy Efficient Cleanrooms: Variable SpeedPumping

Cleanroom energy benchmarking data shows that chiller plant designs and operating efficiencies varied significantly from cleanroom to cleanroom. While system optimization is critical to the overall energy efficiency of chiller plants, the operating efficiency of chilled water and condenser pumps, along with chiller efficiency and cooling tower efficiency, is a major factor in the overall system efficiency. The design and operating efficiency of water pumps directly affects energy use for such facilities. Figure 1 shows benchmarked HVAC energy end use in a semiconductor cleanroom facility. In this case, the water pumps collectively accounted for 17% of the total energy use. Figure 2 shows the electric power demand of the components in a chiller plant system. Pumps accounted for 18% of the total power demand for the whole chiller plant. It is important to design, select, operate, and control water-pumping systems to achieve high efficiency and to lower life-cycle costs for cleanrooms and their adjacent spaces