Emerson Network Power's (www.liebert.com) Liebert CW is a chilled water-based computer room air conditioning unit (CRAC) designed to offer improved energy savings within large data centers. The Liebert CW is a precision cooling system available in upflow and downflow configurations, and in cooling capacities up to 181 kW.
The system, which uses existing building chilled water supply as the cooling source, offers precision cooling and humidity control matched to the needs of data center equipment. Larger downflow models are available with optional energy-efficient EC plug fans, which the company says can achieve the highest level of energy efficiency. Both upflow and downflow models in all capacities are available with optional variable speed drive fans to improve energy efficiency over standard fan operation.
The Liebert CW system uses existing building chilled water supply as the cooling source to provide precision cooling and humidity control matched to the needs of data center equipment.
A recent Emerson Network Power analysis of data center energy usage found that cooling systems comprised of cooling and air movement equipment can account for approximately 38% of energy consumption. Independent tests of the energy efficiency of different types of fan systems found that in raised-floor data centers, where the EC can be used to its best advantage, the plug fan offers the lowest annual operating cost.
Liebert CW also features a proprietary iCOM control system that enables multiple units to communicate and operate as one system, providing control of temperature and humidity across a room while optimizing the efficiency of the entire cooling system.
Ron Spangler, senior product manager, Liebert Precision Cooling/Emerson Network Power, comments, Our performance test results showed that the EC plug fan saves 30% more energy compared to a centrifugal fan at full speed. When the iCOM controls lowered the fan speed by only 20%, EC plug fans provide 65% energy savings in large data centers with chilled water cooling systems.
In large data centers with chilled water systems, an integrated approach to dissipating high heat can be applied by combining the room-level cooling offered by the Liebert CW and the targeted cooling provided by the Liebert XD heat density cooling solution. The CW provides base-level cooling and humidification while the heat generated by high-density, rack-mounted electronic equipment is removed at its source by the XD.
With the Liebert CW, which is based on the design of the Liebert Deluxe System/3 Chilled Water system, customers may also purchase remote monitoring service for critical support equipment. Remote monitoring enables Emerson Network Power's Liebert Services business to monitor systems, predict and troubleshoot potential issues, and diagnose and respond to problems. —M.V.