Type of Cooling
Ambient Conditions
Ti = Temperature inside the
Enclosure
Ta = Ambient Temperature
Cooling Platform
Assembly
Type
approx. Noise Level
IP Protection
free standing
0 dB(A)
original
protection is
unaffected
39 to 71 dB(A)
protection will be
down graded, a
filter mat is
required
unaffected,
*1)
Natural Convection
Ti > Ta
closed cabinet, open cabinet,
subrack, case
Filter Fans
Ti > Tu
subrack, case, closed cabinet
free standing,
in the corner,
side-by-side
Fan Trays
Ti > Ta
closed cabinet, open cabinet,
subrack, case
free standing,
in the corner,
side-by-side
34 to 67 dB(A)
Air/Air Heat Exchangers
Ti > Ta
closed cabinet, indoor and
outdoor area
free standing,
in the corner,
side-by side
55 to75 dB(A)
Air/Water Heat Exchangers
Ta ≤ 70 °C
closed cabinet, indoor and
outdoor area
free standing,
in the corner,
side-by -side
45 to 65 dB(A) *6)
unaffected see
t*2)
Cooling Units
Ti ≤ 55 °C
closed, relatively dense
cabinet, also for outdoor area
free standing,
in the corner,
side-by-side
60 to 81 dB(A)
unaffected see
*2)
∆ T to75 K possible
specific cooling, components
and plug-in units, very
occoasionally room cooling
internally,
directly in
equipment
noise generation only through unaffected see
additionally fans
*3)
see *5)
speicific cooling, components
and plug-in units, air and fluid
cooling
internally,
directly in
equipment
noise generation only through unaffected
additionally fans
*3)
see
largely independent
specific cooling, components
and plug-in units, indoor and
outdoor deployment
internally,
directly in
equipment
unaffected
*4)
see
Peltier Elements
Heat Pipes
Vortex Pipes
above 80 dB(A)
Cooling Capacity
ca. 600 W for open cabinets,
ca. 500 W for closed cabinets
for an air flow volume of 700
m3/h and ∆T=20K to 4.7 kW for
servers, ny experience only to 2
kW for electronics cabinets
optional
Regulation/Monitoring
none
rarely with temperature dependent
speed control, alarm signal with
fan failure, monitoring of filter mat
dirt
temperature dependent speed
see to 2 KW for open cabinets, for
control, alarm signal with fan
closed cabinets considerably less
failure
specific thermal rating between
unaffected see
15 and 150 W/K, so with a
*2)
∆T=25K 3750 W is possible
up to 350 W
thermostacontrolled, micro
controller
self-regulating
the cooling performance and
noise level can be controlled
heat flux density ca. 40 W/cm2 through the temperature
dependent speed control of the
fans
between 40 W and 3 kW
thermostat
Disadvantages
low purchase and operating costs, easy
operation in ambient temperatures impossible, relatively
assembly and maintenance, larger cooling low static pressure increase, sensible use in a polluted
perfomance possible, air flow direction easily area only possible with filter mat, which is maintenancechangeable from intake to expulsion
intensive
low purchase and operating costs, low
assembly height, large air flow volume
possible, direct component cooling possible
through customer specific fan assemblies,
temperature-controlled fan speeds and
monitoring possible as standard, simple
exchange for maintenance purposes
rarely with temperature dependent filter-free system, easy assembly, IP
speed control, alarm signal with
protection of the server cabinet largely
fan failure
unaffected
temperature dependent speed
some suppliers state 40 kW, as control, alarm signal with fan
standard at present ca.20 kW failure, monitoring of water flow
seem to be established
temperature by using a 3-way
valve
ca. 200 W up to above 4 kW
Advantages
no additonal cost, no increased noise level,
operation impossible in ambient temperatures, with higher
IP protection remains unchanged, no
ambient temperatures almost unuseable
maintenance
takes up additonal space in the 19" plane, with higher
ambient temepratures almost unuseable, degree of
effectiveness highly dependent on the distance to
neighbouring plug-in units and their density, high noise
level with plug-in units with more than 3 fans
operation in ambient temperatures impossible, for LLWT
with vertical airflow, i.e. air intake and expulsion above
each other on the same side, see *7)
suitable for large cooling capacities, nonsensitive against environmental pollution and cold water required, the cooling medium water must not
therefore filter-free system, IP protection for short circuit during operating failure, for LWWT with
server cabinets largely unaffected, low noise vertical air flow, i.e. air intake and expulsion above each
level, suitable for the use in ambient
other on the same side, see *7)
temperature, temperature-controlled
suitable for cooling capacities to 4kW in
ambient temperatures, IP protection of the
server cabinet largely unaffected
action reversal from cooling to heating
possible through simple reverse polarisation,
use possible without movable parts,
operates in all assembly location,
temperaturen to 150°C possible, suitable to
cool air, fluids or firm matter, use in ambient
temperature possible.
unpowered circulation, no emmission of
harmful substances during failure, heating
and cooling zones can be strictly separated
from each other
high noise level, the cooling medium used until R134a is
not 100% environmentally friendly, with polluted air a filter
mat has to be used, for cooling equipment with vertical air
flow, i.e. air intake and expulsion above each other on the
same side, see *7)
bad energy efficiency level (between 0.5 and 0.75),
relatively high weight in relation to the active cooling
surface
degree of effectiveness very reliant on the installation site
of the heat pipe, in order to realise large performances the
heat exchanging area has to be enlarged and an enforced
air cooling has to be integrated, this will result in the fact
that the heat pipe becomes heavier and in some cases
also much more noisy
relatively low acquisition costs, maintenanceair pressure is a must, high air pressure use to 4.300 l/min,
free, cold air flow can be directed specificall,
very noisy
operation in ambient temperatures possible
*1) Plug-in fans are open systems with IP20
*5) use adapted to envirnmental conditions
*2) durch die standarmäßige Abdichtmaßnahmen bleibt gewöhnlich IP54 gewahrt, Höhere Schutzarten möglich
*3) only with internal use; otherwise dependet on the gasketing measures
*6) dependent on the cooling capacity/air capactity
*7) components that take air in at the front and expel at at the rear (e.g. servers), as a rule require horizontal air cooling
*4) for use with closed systems to IP56