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U.S. Government Study Finds Variable-Speed Screw Chiller Technology
One of the U.S. government’s testing agencies recently found that a variable-speed screw chiller consumed less energy and offered a greater range of operating conditions than alternative water-cooled chiller technology.
The findings of the study, which was overseen by the General Services Administration and conducted by scientists from the Oak Ridge National Laboratory in the Sidney Yates Building in Washington, D.C., align with Carrier’s view that variable-speed screw chillers, like the AquaEdge® 23XRV, are among the most robust for modern, efficient chilled water plants.
Further, while not endorsing, recommending or favoring any one brand of chiller, the study recommended “broad deployment of VSS chiller technology for new installations, end of life replacements, and energy savings retrofits in facilities across all climate zones.” Carrier, a world leader in high-technology heating, airconditioning and refrigeration solutions, is a part of UTC Climate, Controls & Security, a unit of United Technologies Corp. (NYSE: UTX).
The government-funded study is part of the Green Proving Ground program, which evaluates next-generation building technologies in real-world operational settings. This study did a side-by-side comparison of a variable-speed screw chiller with a variable-speed direct drive oil-free centrifugal chiller with magnetic bearings – also referred to as a maglev centrifugal chiller or MLC.
Both machines were installed in the existing machine room at the Sidney Yates Building and connected to common chilled and condenser water systems, minimizing the number of variables for a true head-tohead comparison.
When compared across a broad range of operating conditions, the variablespeed screw chiller consumed 11 percent less energy than the maglev centrifugal chiller. Based on the data, the variable-speed screw chiller also has an equipment price that is more than 30 percent lower than the maglev centrifugal chiller with the same cooling capacity.
“Carrier has long believed our variable-speed direct drive screw compressor technology provides superior efficiency compared to the maglev centrifugal and the Green Proving Ground study corresponds to our belief. It’s another data point affirming the wide operating parameters of Carrier’s AquaEdge 23XRV,” says Chris Opie, director, marketing, Carrier Commercial Systems.
“Our team continues to develop solutions to meet the growing desire for highly efficient commercial climate control.” The study was conducted as part of the government’s effort to drive down energy costs in federal buildings and concluded with a recommendation for broad deployment of variable-speed screw chiller technology.
“A more efficient, lower cost chiller makes for simple math when calculating lowest life cycle cost alternatives,” adds Opie. “Carrier applauds the U.S. government for its commitment to sustainable buildings and we were pleased to hear about the Oak Ridge National Laboratory’s test results. We continue to invest in heating and cooling products that are among the most efficient and we strive to help the government and private industry in their goals to reach new levels of sustainability in their facilities.
With our history of innovation and commitment to leading the industry, Carrier is well positioned to help customers meet their sustainability and energy-efficiency targets.” To learn more about Carrier’s variable-speed screw chiller offerings, visit Carrier.com.