Rittal Liquid Cooling Package
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3 Device description
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3
Device description
3.1
General functional description
The Liquid Cooling Package DX (DX = Direct Expansion)
is essentially a split air conditioning unit used to dissipate
high heat losses from server enclosures or for the effec-
tive 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 (LCP Rack DX) or from
the hot aisle (LCP Inline DX) and thus routed through the
heat exchanger module.
In the heat exchanger module, the heated air is directed
through a heat exchanger (coolant evaporator), and its
thermal energy (heat losses from the server) is trans-
ferred to the coolant. This causes the coolant to change
from a liquid to a gaseous state. As a result, the air is
cooled to a freely selectable temperature within the au-
thorised parameters and then routed directly in front of
the 482.6 mm (19") level in the server enclosure (LCP
Rack DX) or into the cold aisle (LCP Inline DX).
In its delivered state, cold air from the LCP Inline DX is
expelled to the front; it is also possible to expel the cold
air on both sides, or by mounting a side panel, at one
side of the device.
Fig. 1:
Air routing on the LCP Rack DX – top view
Key
1
Air inlet
2
Heat exchanger
3
Air outlet
4
Fan module
5
2nd air inlet
6
2nd air outlet
Fig. 2:
Air routing on the LCP Inline DX – top view
Key
1
Air inlet
2
Heat exchanger
3
Fan module
4
Air outlet
The temperature of the impelled cold air is controlled by
continuously comparing 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.
The temperature differential between the setpoint and
the warm air intake is used to calculate and control the
fan speed.
Any condensate incurred is collected in the condensate
collecting tray integrated into the LCP DX below the heat
exchanger, and from there is routed outside via a con-
densate discharge hose.
3.2
Air routing
3.2.1
General
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 units and is unable to
flow past at the sides.
Targeted air routing inside the server enclosure has a
major effect on the heat loss to be dissipated.
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