air inlet at walls

[ZDR1985]

I have a battery room with 500 L/s exhaust fan. This room is cooled by decorative split unit. The thing is, there is no make up air provided for the exhaust. I cannot put air handlers as there is no space for it within the building / room. Can I just put air inlet (sand trap louver with filter) at the external wall of the room and additional split unit to cool the additional load of the entering hot air? The outside design temp is 50 degC.

 

[EnergyProfessional]

What is the purpose of the exhaust fan? for actual cooling, or ventilation (battery gas etc.)

if you have lead-acid batteries, NEC and other codes are concerned about hydrogen. Other type of batteris amy have other issues and can explode/combust. so this may require some more thinking than just the air intake.

for batteries, you don't want them to get cold as they lose capacity. Depends on your climate.

You din't provide a lot of information.

 

[ME27272727]

To add to what EnergyProfessional has stated, if the exhaust fan purpose is to remove air from a battery charging room with lead-acid batteries, then you are dealing with Hydrogen. Check NFPA for required ventilation and sensors. Some possible requirements: XP fan, aluminum ductwork, LEL detectors, high exhaust inlets.

 

[ZDR1985]

Yes the exhaust fan is for the hydrogen. My concern is 500 L/s exhaust without makeup air?

 

[EnergyProfessional]

Mass balance. If you don't have make-up air, the space will be negative and draw air through all the crack from adjacent spaces. that may be what you want since you don't want hydrogen to diffuse int eh building.
At some point the EA fan isn't strong enough and you can't meet your 500 l/s. then you need to create large opening to adjacent spaces, or provide Make-up air.

 

[ReverseCycle]

How big is your battery room? 500 L/s is a large quantity of air! Is this according to your local code requirements?

Also 50 deg C ambient conditions is very high! I would consider an air to air heat exchanger to reduce your AC unit load.

 

[HVACMech]

You should put in a transfer from an adjacent space with a fire/smoke damper in the opening. That way you don't pull in unconditioned air into your room.