Stahl ISpac 9162 Serie Betriebsanleitung Seite 15

english
b) Natural convection in open cabinets
• Function: the heat is removed by cool air flowing through the devices
• Requirements:
- inlet and outlet ports in the lower and upper ends of the cabinet
- the air flow path must be kept free from obstacles.
• Result: Depending on the engineering the improvement can reach a two times higher
power dissipation as with a)
c) Forced ventilation with heat exchanger in closed cabinets
• Application: when either the harsh environment or the high dissipated power do not
allow natural convection
• Function: a heat exchanger with a fan pulls the air into the cabinet and pushes it into the
heat exchanger plates that are cooled by the external ambient air moved by a second
fan.
• Result: Depending on the engineering the improvement can reach a 5 or 6 times
higher power dissipation as with a)
d) Forced ventilation in open cabinets
• Function: the filtered air is taken from the bottom cabinet openings by one or more fans,
flows through the devices, and finally exits at the top of the cabinet.
• Calculation of the required air flow:
) / ∆t
Q = (3.1 * P
70%
Q [m³/h] required air flow
P [W] dissipated power (70 % of max. power dissipation)
70%
∆
t [°C] allowed temperature rise in the cabinet
e) Air conditioned cabinets
• Application: for hot climates - it is possible to reach a cabinet temperature equal or even
lower than the ambient temperature
• Function: a specific refrigerating system or the existing air conditioning system can be
used for cabinet conditioning
Transmitter supply unit with limit values type 9162
Operating instructions
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