HEPA Filter for low temp (-15C)

[blackheart_hui]

Hi guys, I new to this group & glad to join the group to discuss Refrigeration.I need some help for conditioning of the air. If anyone have come across the following problems, please advise.Previously, I have a fresh air system for food process. Air is conditioned through 3 AHUs to +2C & is filtered by HEPA from AAF of AAF AstoCel 1. Recently I done a upgrade of the system & brought the air temp down to -15C. However I noticed that HEPA freezed after 30 min of operation & system pressure went from 1.6KPa to 4KPa. When we revert back to the old parameters, system pressure went back to 1.6KPa.Therefore I am asking if anyone have done a project like this & have come across this problem. Also, do anyone know if there are HEPA filtration for temp as low as -10/-15C?Thanks in advance, Hui

[aramis]

Never had this problem in particular, though I know you have to change the type of filter if you have now high relative humidity or the velocity profile changed.

You should contact the filter supplier.

[blackheart_hui]

We are currently seeking advice from AAF on the suitable type of HEPA.
The air velocity was changed from 143 to 165m3/min

[mad fridgie]

Your filter is not freezing up, it just becoming blocked with ice particles that are suspended in the air.
Think of it as "Ice dust"

[blackheart_hui]

Hi mad fridgie,

That certainly ring a bell!!! I noticed the area after my -15C coil & before the HEPA to be fill with 'snow'. You know of any product on how we can 'catch' these dust out from the air before reaching the HEPA?

Thanks, Hui

[aramis]

It looks like you are working in an oversaturated region, thus the fog.

Drying the air may help.

[install monkey]

if its a fresh air system the surely you fiter the air then cool it-thus eliminating your hepa filters frosting up

Hi guys, I new to this group & glad to join the group to discuss Refrigeration.I need some help for conditioning of the air. If anyone have come across the following problems, please advise.Previously, I have a fresh air system for food process. Air is conditioned through 3 AHUs to +2C & is filtered by HEPA from AAF of AAF AstoCel 1. Recently I done a upgrade of the system & brought the air temp down to -15C. However I noticed that HEPA freezed after 30 min of operation & system pressure went from 1.6KPa to 4KPa. When we revert back to the old parameters, system pressure went back to 1.6KPa.Therefore I am asking if anyone have done a project like this & have come across this problem. Also, do anyone know if there are HEPA filtration for temp as low as -10/-15C?Thanks in advance, Hui

[blackheart_hui]

hi guys, thanks for all your help.
I shifted the HEPA upstream before my -15AHU. Also explained the mystery for the chocked filter. Thanks You