Compressors Room Ventilation

[Kannn]

Hello There
Iam about to start project in my plant and i need your help guys
we have a compressors room and i need to install ventilation system for the room
there is :
1- Two Compressors Water Cooled ( Compressed Air Flow : 710 m3/hr ) (Motor Kw : 75 ) There is a cooling fan to cool the motor and also to cool the oil cooler (air cooling flow rate : 12240 )
2- Two Compressors Air Cooled ( Compressed Air Flow : 841 m3/hr )(Motor Kw : 90 ) (Air Cooling Flow Rate : 17620 m3/hr )

all compressors has an exhaust duct to take the hot air outside the room

The Room Temp in summer gets high and sometimes trips the compressors
My Questions is
1- Do I need to install supply fans with exhaust fans , Or Just Supply fans and already there is an exhaust for each compressor
2- What is the total inlet flow rate needed , Do I Consider also the water cooled compressors in my calculations ?

 

[CodyK]

1. If you're cooling with exhaust fans, you would only need louvers to bring in supply air
2. Hopefully others can answer this question as well. I was told by an experienced designer to size based on a certain number of ACH (which didn't seem exact enough for me). I found a paper called "Formulas for Cooling with Exhaust Fans" by Mirza M. Shah; in that paper, it gives the equation Q (cfm) = H (sensible heat gain in Watts) / (0.353 * (1 - Outside Air Temp/Inside Room Temp)) and that is how the exhaust fan size is chosen. If the water cooled compressors give off heat to the room, then yes they should be included. However, I wouldn't think that would be the case.

 

[LittleInch]

How big is your exhaust fan in volume terms?

How hot is the incoming air compared to your trip temperature?

Where does the water cooling go? inside the room or out?
You will need to allow for the electrical motor cooling of the water cooled compressors at the very least and maybe a little for the water cooled depending on surface temperature of the compressors.

At the worst you will need to supply your cooling fan volumes (30,000 m3/hr)

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Compositepro]

Air cooling compressors on hot days is a major problem. I have seen it many times. Ambient temperature on hot days can get close to allowable temp. limits for compressors, so little cooling is available to begin with. Re-entrainment of hot exhaust air with supply air is common.

 

[EnergyProfessional]

Talk to compressor manufacturer about their requirements.

the ventilation to the room should be capable of at least the fan-flowrates of the compressor. if much higher, it won't do much good. If lower, it may starve the compressor depending on ambient temps. Also consider other loads in this space that add heat. Obviously if your ambient temperature is close or above what the compressor requires, you need refrigeration.

You could do a variable flow or some other control based on room temperature so you can reduce the flowrate in colder months.

I'd also investigate if all compressors are required during the peak ambient temperature times.

 

[LittleInch]

Also if the air intakes into the compressor are in the room you need to ADD that to the cooling exhaust rate to get your inlet air rate.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.