Thread: Ventilation System for Diesel Generator Set

1. Ventilation System for Diesel Generator Set

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Hi all,

I was assigned to design a standby diesel generator set for a shopping mall in Malaysia which holds a Power Rating of 1500kVA. The genset room is located at Basement 1, thus I am designing for a remote radiator system.

Referring to the attached catalog, the amount of heat rejected to the coolant is 511kW - and I have designed the required capacity fan for the radiator.

The question is, do I still have to provide ventilation system for the Genset Room itself since it was mentioned that there will be heat rejected from the engine and alternator to the room - about 181.9kW?

I would really appreciate some help here.

Thank you.

Regards,
Hafiz
Mech. Engr

2. Where is the generators exhaust venting to?

3. Obviously that heat must be dispersed in some manner. You state that you have designed a required fan capacity for the radiator heat if this is true then wouldn't it be relatively easy to increase the capacity of that fan to deal with the additional engine heat.

4. Originally Posted by Cake of Doom
Where is the generators exhaust venting to?
Dear Cake,

The exhaust will be discharged outside to an open air.

5. Originally Posted by JAlberts
Obviously that heat must be dispersed in some manner. You state that you have designed a required fan capacity for the radiator heat if this is true then wouldn't it be relatively easy to increase the capacity of that fan to deal with the additional engine heat.
Dear J,

I was thinking the same way too. But in my company, generator system is handled by electrical engineer. So most of them just ignore the heat dissipated out from the engine & alternator. I am now trying to fix everything up. Thanks for the opinion.

6. All,

Check out the attached document from CAT.

proper-engine-room-ventilation.pdf

Ventilation Fan Sizing

The following equations provide the proper airflow (cfm or m3/s) velocity for a given genset installation, assuming 100°F
(38°C) ambient temperature:

Airflow (cfm or m3/s) should increase approximately 10% for every 2,500’ (760m) above sea level.

V (cfm) = H + Engine combustion air
0.07 x 0.24 x delta T
V (m³/min) = H + Engine combustion air
1.099 x 0.017 x delta T

Where:

V = ventilating air
delta T = Permissible temperature rise in engine room (degrees F or C)
Density of air at 100°F = 0.07 lb/cu ft (1.099 kg/m³)
Specific heat of air = 0.24 Btu/°F (0.017 kW/°C).

7. what are the units for H and T , we should consider.
In my case the outside ambient is 40 degC and the generator room can be maintained at 39 deg C. There are 2 DGs running with 1600 kw each. Can some one tell me the ventilation fan capacity???