Specifications

System Description
1
1.0 SYSTEM DESCRIPTION
The Liebert XD™ family of cooling units delivers efficient, sensible cooling to high-heat environ-
ments. XD systems are designed to cool computer racks and hot zones in a data center or computer
room without taking up expensive floor space for cooling components.
The Liebert XD family includes:
• XDO—XD Overhead unit, suspended from the roof structure
• XDV—XD Vertical unit, mounted on top of the equipment cabinet or suspended from the roof
structure
• XDP—XD Pumping unit
• XDC—XD Chiller unit
• XDA—mounted on the front or rear of the equipment cabinet
Systems combining XDO, XDV units with XDP or XDC units can remove more than 16 kW of heat per
cabinet.
The Liebert XD system also performs at high efficiency rates. Properly spaced cooling modules and
the XD system’s fluid phase change technology, combine to reduce an XD system’s energy consump-
tion to at least 18% less than a traditional cooling system.
The XD family maintains this energy efficiency by employing the heat absorption properties of a liq-
uid (pumped refrigerant) through phased changes. Coolant is pumped as a liquid, becomes a gas
within the heat exchangers of the cooling modules (either the XDO or XDV) and then is returned to
either the XDP or XDC where it condenses to a liquid. This eliminates the compression cycle required
by traditional systems. And, if a leak were to occur, the environmentally friendly coolant would
escape as a gas, causing no harm to critical equipment (see Figure 1).Because no compressor is used
in the circuit, no oil is needed.
Figure 1 Pressure enthalpy diagram - refrigerant
Traditional
Vapor
Compression
Cycle
Pumped
Two-Phase
Cycle
VaporLiquid/Vapor Mix
XDO/XDV
ENTHALPY
PRESSURE
Liquid