Carrier Corp.’s 17DA industrial water chillers were selected by the Mayo Clinic and Oklahoma State University (OSU) for their expansion projects. The installation at OSU culminates a three-year benchmark operating cost study in which the 17DA chiller saved the university nearly $1 million in operating costs.

The variable speed 17DA chiller has a capacity performance range of 3,000 to 5,000 tons and uses environmentally sound HFC 134a refrigerant. To increase operating efficiencies, a steam turbine or electric motor can be selected to match the most economical fuel source available.

Mayo Clinic’s ongoing expansion of its Rochester, MN, facility required an additional 4,000-ton open-drive chiller to operate on steam exhausted from the steam turbine generator at its utility plant. Carrier’s 17DA turbine drive chiller was selected based on its ability to efficiently meet load demand and fit in the existing equipment room. Working side-by-side with a pre-existing installation of Carrier 17-series water chillers, the new 17DA unit is part of the system delivering more than 20,000 ton-hours of chilled water to 25 buildings.

A three-year benchmark study by OSU compared the efficiency of two identical Carrier 4,200-ton chillers – one using a fixed-speed drive and the other with a variable-speed drive. According to Bill Burton, OSU’s utilities manager, test results demonstrated the efficiencies of the 17DA’s variable speed design, saving the university $1 million. “The study confirmed that the variable speed chiller offers greater efficiency and lower operating costs,” he said.

The Carrier 17DA varies the compressor’s speed, which proportionately affects power consumption at part load. This increases refrigeration cycle efficiency and thereby decreases the energy costs for cooling.

“Energy efficiency is one of the top concerns facing today’s institutional facility engineers and they are demanding real cost savings from their equipment,” said Harold Valencia, product sales and marketing manager at Carrier. “Carrier’s 17DA variable speed drive chillers provide users with a flexible, low-operating cost solution that enables them to meet their energy savings goals.”