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MI00/10056 rev. 8 — 05/2006-- page
29
4.4 Ventilation
UPS can work in a continuous environment within 18
°
F[-10
°
C] to 104
°
F [+40
°
C ] temperature range, although,
ideally the ambient temperature should be below 78
°
F [25
°
C].
The heat, dissipated by the UPS (indicated on figure 7), is extracted by internal fans and then dissipated into the air.
The heat can be removed from the UPS room by a forced cooling ventilation system or, alternatively, an air
conditioning system.
The required air changes per hour will depend on the UPS rating and this heat loss and on the cooling air temperature.
To calculate the required air flow for the dissipated power, the altitude and the cooling air temperature, the following
equation can be used:
• P
d
V = 2770 - - - - - - • e
(0.125 h T
k
/ T
0
)
T
r
- T
k
with: V = air flow [mc/h]
P
d
= total dissipated power [kW]
T
r
= max. temperature allowed into the room [104°F = 40°C = 313°K]
T
k
= Temperature of input cooling air
T
0
= 273 °K
h = altitude above the sea level [km]