Cleanroom Cooling Air changes vs heat gain
Cleanroom Cooling Air changes vs heat gain
(OP)
I am designing a Pharma clean room. It requires 40 ACH or 6500 cfm. The only heat gain in the room is basically lights and people.
There is 1650 cfm of exhaust required. It is negative pressure with respect to surrounding spaces so I am gaining approximately 560 cfm
from pressure infiltration.
My question is what is the best way to provide the high ACH without large reheat for the small cooling load?
Any thoughts would be great.
Thanks
There is 1650 cfm of exhaust required. It is negative pressure with respect to surrounding spaces so I am gaining approximately 560 cfm
from pressure infiltration.
My question is what is the best way to provide the high ACH without large reheat for the small cooling load?
Any thoughts would be great.
Thanks





RE: Cleanroom Cooling Air changes vs heat gain
RE: Cleanroom Cooling Air changes vs heat gain
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RE: Cleanroom Cooling Air changes vs heat gain
You are returning so much air, that yoru load is very small. The problem you will find ios the load is so small compared to the airflow required. Face and bypass is a good idea. I oversided my unit so I could get 2 speed compressors, and it mostly runs at low speed.
If your using DX, you can also try digital scoll compressors with modulating hot gas reheat.
knowledge is power
RE: Cleanroom Cooling Air changes vs heat gain
It is a chilled water unit.
It is also correct that the 560 comes from conditioned airlocks.
I also have hot water reheat on volume control boxes. The boxes are constant volume for balancing, just for the air changes that remain the same.
RE: Cleanroom Cooling Air changes vs heat gain
RE: Cleanroom Cooling Air changes vs heat gain
RE: Cleanroom Cooling Air changes vs heat gain
EA 1650 CFM
Pressure airflow into room 560 CFM
RA 5310 CFM
Another problem I am having is sizing the cooling.
The space requirements are 68°F/<60% RH. The heat gain in the room is only 14,000 btu/hr very small. I will definitely have to reheat.
What I am trying to do is provide a make-up air unit to cut latent load and recirc with sensible only.
I am trying to figure out what leaving unit dew point I need to provide to maintain space conditions.
RE: Cleanroom Cooling Air changes vs heat gain
On pharmacy prep rooms I like to oversize airflows a bit and then provide balancing devices on all air streams, including the transfer air, if possible. If the room is poorly constructed or too tight, then you will have options to make sure you are within the required pressure differential ranges between the rooms. I've seen burned out door operators because the pressure differential was actually TOO high and it was too difficult to open doors.
RE: Cleanroom Cooling Air changes vs heat gain
RE: Cleanroom Cooling Air changes vs heat gain
RE: Cleanroom Cooling Air changes vs heat gain