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Thermal management system
No need for a thermal
system;
a circulation fan may be used to
even out the temperature.
No need for a thermal
system; a circulation fan may be used
to even out the temperature.
6
Determining the type of thermal device and its power: Psyst
Need for a thermal system:
resistance heater
1/ Permanent operation
of the switchboard
Psyst = K
S (Ts
min
– Te
min
) – Pd
2/ Discontinuous operation
Psyst = K S (Ts
min
– Te
min
)
If Ts min < Ti min
If Ts min > Ti min
If Ts max < Ti max
If Ts max > Ti max
Need for a thermal
system:
ventilation, fan,
exchanger,
cooling unit.
Psyst = Pd – K S (Ts
max
– Te
max
)
Psyst = 800 – 5.5 4.13
(40 – 35)
~ 690 W
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Ts max ≥ Te max +5 °C
Temperature conditions
Solution
Advantages
Constraints
Avoid hot
Install circulation
Highly economical solution
The amount of heat evacuated
spots.
fans in the enclosure.
requiring no maintenance,
is relatively low.
easy to install;
Installation IP conserved.
Oversize the enclosure
Economical solution
The amount of heat evacuated
or the wall-mounting enclosure. requiring no maintenance,
is relatively low, larger dimensions.
easy to install;
Installation IP conserved.
Install ventilation louvres.
Highly economical solution
The amount of heat evacuated
Final temperature Ts max
requiring no maintenance,
is low, it depends on the
desired in the enclosure
easy to install.
layout of the components,
at least 5 °C higher
reduced IP (entry of dust).
than the ambient temperature
Te max.
Install fans
Economical solution, easy
Regular filter maintenance.
for introducing fresh air.
to install; large amount of
IP slightly reduced.
heat evacuated; possible
temperature control.
Ts max ≥ Te max + 5 °C
Use an air-air
Easy to install;
Regular filter maintenance.
exchanger.
IP conserved during installation;
temperature control
as standard; easy maintenance.
Use a cooling
Easy to install;
Regular filter maintenance,
unit.
allows the evacuation of large
cannot be used beyond an
amounts of heat, even
ambient temperature of 55 °C.
Final temperature Ts max
when the ambient temperature
desired in the enclosure
is high, IP conserved during
lower than the ambient
installation, temperature
temperature Te max +5 °C.
control.
Use an air-water
Easy to install;
Needs a water circuit;
exchanger.
allows the evacuation of large
consumption if supplied
amounts of heat, even
by the water mains.
when the ambient temperature
is high, IP conserved during
installation, temperature
control, no filter to maintain.
Outside temperature lower
Heat using a
Economical, reliable;
Energy consumption;
than the lowest acceptable
resistance heater.
see temperature in the table.
space taken up in the
ambient temperature
enclosure.
for the switchgear.
Risk of condensation.
Heat using a resistance
Economical, reliable;
Energy consumption;
heater in order to
the humidity in the switchboard
space taken up in the
maintain the temperature
can be regulated.
enclosure.
beyond the dew point
temperature.
D =
Psyst
(Ts max-Te max)
3.1 m
3
/h
q =
Psyst
(Ts max-Te max)
wk
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