Results 1 to 8 of 8
  1. #1
    blackheart_hui's Avatar
    blackheart_hui Guest

    HEPA Filter for low temp (-15C)



    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



  2. #2
    Join Date
    Feb 2012
    Location
    Bolivia
    Posts
    270
    Rep Power
    14

    Re: HEPA Filter for low temp (-15C)

    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.

  3. #3
    blackheart_hui's Avatar
    blackheart_hui Guest

    Re: HEPA Filter for low temp (-15C)

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

  4. #4
    Join Date
    Aug 2009
    Location
    New Zealand
    Age
    59
    Posts
    2,556
    Rep Power
    26

    Re: HEPA Filter for low temp (-15C)

    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"

  5. #5
    blackheart_hui's Avatar
    blackheart_hui Guest

    Re: HEPA Filter for low temp (-15C)

    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
    Attached Files Attached Files

  6. #6
    Join Date
    Feb 2012
    Location
    Bolivia
    Posts
    270
    Rep Power
    14

    Re: HEPA Filter for low temp (-15C)

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

    Drying the air may help.

  7. #7
    Join Date
    Oct 2007
    Location
    manchester
    Age
    50
    Posts
    5,707
    Rep Power
    45

    Re: HEPA Filter for low temp (-15C)

    if its a fresh air system the surely you fiter the air then cool it-thus eliminating your hepa filters frosting up
    Quote Originally Posted by blackheart_hui View Post
    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

  8. #8
    blackheart_hui's Avatar
    blackheart_hui Guest

    Re: HEPA Filter for low temp (-15C)

    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

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •