3 Device description
EN
8
Rittal LCU DX
3
Device description
3.1
General functional description
The Liquid Cooling Unit DX (DX = Direct Expansion) is
essentially a split cooling unit used to dissipate heat
losses from server enclosures or for the effective cooling
of devices built into a server enclosure.
The air routing in the LCP DX supports the "front to
back" cooling principle of the devices built into the server
enclosure. The hot air expelled by the devices in the
server enclosure is drawn in by the fans at the rear di-
rectly from the server enclosure or Micro Data Center
and then routed through the heat exchanger module.
In the heat exchanger module, the heated air is directed
through a heat exchanger (refrigerant evaporator), and
its thermal energy (heat loss from the server enclosure)
is removed from the refrigerant via evaporation. This pro-
cess cools the air to a freely selectable temperature, and
it is then routed directly in front of the 482.6 mm (19")
level in the server enclosure or Micro Data Center.
The setpoint (outlet temperature from the cooling unit or
server air intake temperature) may be set in the range
+18°C to +28°C.
Fig. 1:
Air routing on the LCU DX – Top view
Key
1
Installed equipment in the server
2
Server enclosure/Micro Data Center
3
Air outlet
4
Heat exchanger
5
Fan
6
Air inlet
In the LCU DX, the temperature of the incoming cold air
(server air intake) is controlled by continuously compar-
ing the actual temperature with the setpoint temperature
(preset to +22°C).
If the actual temperature exceeds the setpoint tempera-
ture, the speed of the compressor is automatically in-
creased, providing a greater cooling output from the
heat exchanger, until the setpoint temperature is
reached.
In the LCU DX, the measured temperature of the extract-
ed warm air is used to determine and control the re-
quired fan speed.
Any condensate incurred is collected in the integral con-
densate collecting tray below the heat exchanger, and
from there is routed outside via a condensate discharge
hose.
3.2
Air routing
In order to achieve sufficient cooling in the server enclo-
sure, it is important to ensure that the cooling air passes
through the interior of the built-in devices rather than
flowing past at the sides.
Targeted air routing inside the server enclosure has a
major effect on the thermal output to be dissipated.
In order to ensure targeted air routing in the system, the
server enclosure should be divided vertically into warm
air and cold air sections. Essentially, this is already en-
sured by the 482.6 mm (19") arrangement and the in-
stallation of "front to back" vented servers. Consistent
sub-division is achieved with additional plastic foam
strips and air baffle plates on the left and right of the
482.6 mm (19") level (see section 13 "Accessories").
If the LCU DX is used to cool a TS IT server enclosure, it
is important that this is sealed, by fitting the enclosure
with side panels, roof and gland plates. Any existing ca-
ble entries should be sealed e.g. using suitable brush
strips. Whilst the system is in operation, both the front
and the rear doors should be kept completely shut. No
slotted doors should be used.
When using in the Micro Data Center, the LCU DX is in-
serted in a sealed safe structure for application-related
reasons.
3.3
Device assembly
3.3.1
Internal unit (evaporator coil)
The internal unit of the LCU DX may be bayed either on
the right or left of a server enclosure or Micro Data
Center. To this end, the internal unit is mounted directly
5
4
3
6
1
2
Note:
The 482.6 mm (19") level must likewise be
completely sealed. This is already the case in
a fully configured server enclosure. With a
partially configured server enclosure, the
open height units (U) of the 482.6 mm (19")
level must be sealed with blanking plates,
which are available as Rittal accessories (see
section 13 "Accessories").
