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525
ClimaSys
Thermal management system
Exampleof calculation and selection
Data
b
b
Enclosure data
v
v
Height: 2000 mm
v
v
Width: 800 mm
v
v
Depth: 500 mm
b
b
Location:
placed on the wall
b
b
Material:
painted sheet-steel enclosure
b
b
Thermal power dissipated by the operational components
Pd: 950 W
b
b
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
b
b
Environment:
low pollution and low dust level
Selection and calculation
The desired maximum temperature inside (Ts
max
) the enclosure is 10°C
higher than the maximum value expected for the outside (Ti
max
).
It is possible to cool the enclosure using the filtered ventilation systems.
Calculation of the required fan (1)
Usage formulas:
Psyst =
Pd - K x S x (Ts
max
- Te
max
)
Flow =
f x Psyst / (Ts
max
- Te
max
)
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
Our example
Psyst = 950 - 5.5 x 4.6 x (35 - 25) = 697 W
Flow rate = 3.5 x 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 x S x (Ts
min
- Te
min
)
Our example: W = 5.5 x 4.6 (15 - 10) = 127 W
Selection from the selection guide of the resistance heaters:
1 resistance heater ref. NSYCR150WU2C
+ 1 thermostat ref. NSYCCOTHC
(1)
Pd
= Thermal power dissipated by the operational
components
S
= 1.4 x W x (H + D) + 1.8 x D x 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
x °C for a solid sheet-steel enclosure
K = 3.5 W/m
2
x °C for a polyester enclosure
K = 3.7 W/m
2
x °C for a stainless-steel enclosure
f
= Coefficient relating to the height above
sea level (value)
0 to 100 m: f = 3.1
100 to 250 m: f = 3.2
250 to 500 m: f = 3.3
500 to 750 m: f = 3.4
750 to 1000 m: f = 3.5
…