As data center managers strive for new ways to design and support higher densities in smaller spaces, Emerson Network Power has introduced the Liebert XDR an innovative rear-door heat exchanger that removes heat from IT racks before it ever enters the data center.†
The Liebert XDR technology was first previewed at Supercomputing 2008, where it was an integral part of Sun Microsystems’ Cooling Door system that fit in the rear of the Sun Blade 6048 modular system.
Throughout the past year, a version of the XDR product was used exclusively by Sun Microsystems as the SCD5600. 
The product is now available globally.
The Liebert XDR microchannel heat exchangers are mounted in a moveable door, which is fixed to a frame attached to the rear of the rack. It relies on server fans for hot air movement across a cooling coil, utilizing a pumped refrigerant that is 700 percent more efficient at removing heat than water.
A pumped refrigerant eliminates any danger of equipment damage from water leakage. Air exits the Liebert XDR at approximately the same temperature as the air entering the front of the rack, neutralizing the heat created by the servers.
“Because the Liebert XDR cools the air exiting the rack before it enters the room, there is no need for fans to move heat across the room to wall or floor-mounted cooling systems,” explains Bob Blough, director of product marketing for Liebert precision cooling at Emerson Network Power.
“Eliminating the cooling fans makes it possible for businesses to realize energy savings of 35 to 48 percent compared to perimeter cooling–let alone the capital cost savings from not needing to expand or build a new facility,” Blough adds.
Able to accommodate both new and existing racks, the Liebert XDR is designed to cool up to 20 kW of rack load. The sleek construction of the Liebert XDR enables the entire cooling unit to be less than six inches deep. The door opens more than 100 degrees, for full access to the internal servers and other equipment, and allows for side-by-side placement of racks in open and closed positions.
The Liebert XDR includes a flexible connection of hard-piped, pumped-refrigerant lines through the rack door’s hinge pivot points, which enables it to be robust and leak-free through more than one million repeated door openings and extended periods of time with no movement. These overhead piping connections are completely static–no moving components will interfere with opening or closing the door.
Pumped refrigerant from a Liebert XDP or Liebert XDC enters the fixed frame and passes through an innovative hinge to the door. The Liebert XDR can be utilized with existing Liebert XD installations, using the same flexible connections and hard piping.
