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selection
Selection and calculation:
The desired maximum temperature inside (Ts
max
) the enclosure is
10 ºC higher than the maximum value expected for the outside (Ti
max
).
It is possible to cool the enclosure using the filtered ventilation systems.
Data
●
Enclosure data
Height:
2000 mm
Width:
800 mm
Depth:
500 mm
●
Location:
Placed on the wall
●
Material:
Painted sheet-steel enclosure
●
Thermal power dissipated by the operational components
Pd: 950 W
●
Information on temperature and the environment:
Maximum desired temperature inside the enclosure
Te
max
: 25 °C
Minimum desired temperature inside the enclosure
Te
min
: 25 °C
Maximum temperature dissipated in the enclosure
Te
max
: 35 °C
Minimum temperature dissipated in the enclosure
Te
min
: 25 °C
Environment:
Low pollution and low dust level
Calculation of the required fan:
Usage formulas:
Psis =
Pd – k
S (Ts
max
– Te
max
)
Flow =
f Psis/ (Td
max
– Te
max
)
Pd: Thermal power dissipated by the operational components
S = 1.4 W (H + D) + 1.8 D H = 4.6 m
2
. According to standard IEC 890
K = Constant defined by the material used to manufacture the enclosure
K = 5.5 W/m
2
°C for a solid sheet-steel enclosure
K = 3.5 W/m
2
°C for a polyester enclosure
K = 3.7 W/m
2
°C for a stainless-steel enclosure
0 to 100 m f = 3.1
100 to 250 m f = 3.2
250 to 500 m f = 3.3
In order to make the calculation, it is necessary to know the height above sea level
of the installation location:
Height above sea level: 800 m
f = Coefficient relating to the height above sea level (value)
Our example:
Psis = 950 – 5.5
4.6
(35 – 25) = 497 W
Flow rate = 3.5
697 / (35 – 25) = 244 m
3
/h
Selection from the fan quick-selection table
1 fan with standard filter ref. NSYCVF300M230PF + 1 grille with standard
filter ref. NSYCAG223LPF + 1 thermostat ref. NSYCCOTHO enable a
flow rate of 302 m
3
/h
The minimum outside temperature is lower than the desired minimum
temperature inside the enclosure.
It is necessary to install resistance heaters:
Calculation of the useful resistance heater
Usage formula
W = k S (Ts
min
-Te
min
)
Our example:
W = 5.5 4.6 (15 – 10) = 127 W
Selection from the selection guide of the resistance heaters.
1 resistance heater ref. NSYCR150WU2C + 1 thermostat ref. NSYCCOTHC
500 to 750 m f = 3.4
750 to 1000 m f = 3.5
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