Electrical room exhaust fan 1

[RMERMP]

what air change can i use to ventilate a electrical rooms where 7 panel boards are installed inside? i was able to find 4-6 air change. can i use this air change? thanks

 

[ZDR1985]

If you are using ambient air, calculate how much air will require to remove heat dissipated by panels based on max temp required inside room. But I reckon you need to air condition the room to protect your equipment not only from high temperature but also humidity, depends on where you from.

 

[RMERMP]

i used 10ACH in the room with 796 sq.m volume. i have no data regarding the heat dissipation of a panel boards. how can i calculate the heat dissipation?

 

[ZDR1985]

Better to ask your electrical engineer, but to give you a rough estimate normally it is 3% of total panel load.

 

[SAK9]

Why ventilate electrical rooms?You are introducing dust and humdity into the room which are No1 enemies of electrical contacts.Just aircondition them with a higher design temp say 28C and have the unit cycle on/off on thermostat.

 

[lukaiENG]

ZDR1985 - 3% seems very high. This number jives with older technology boards with transformers, but it should not be so much for a straight distribution board. Like you said - ask the electrical engineer for the cut sheets for the equipment. Call the manufacturer if you need to.
I agree with SAK9 that they don't need to be ventilated. I normally just put in a nominal CFM rate from my VAV system. For smaller spaces you could naturally ventilate with door grilles.

 

[RMERMP]

The owner wants the EE room to be ventilated. just to remove the heat coming from the panel boards. the total load of all the panel boards is 336.22 kVa. 5% of the total load will be 16.811 kVA. i calculated 172 cfm for the estimated heat dissipation. i not just sure of the Delta T (F) since the outside air in the summertime here in 28.1 degrees C. i used 24 degrees C as the operating temperature of the panel boards. anyone wants to correct my calculation. please do so. thanks.

 

[ZDR1985]

RMERMP where you from?

First, with just ventilation you cannot mainatain 24C inside if your outdoor temp is 28C, even 28C indoor will be unrealistic. Should be air conditioned to do that.

Your delta T will be based on how much temp rise your electrical room will maintain at the peak of summer. I say temperature rise since you are just ventilating, you cannot drop your temperature without airconditioning.

I wonder how you came up with 172cfm.

 

[lukaiENG]

I agree with ZDR1985 on that - there is some very dodgy mathematics going on there. 16.811 kVA and 172CFM leads to a delta T of over 300 degF (~170degC).
RMERMP I think you need to sit down with your supervising engineer and get some training because you seem to be a little bit lost.