Results 1 to 4 of 4
  1. #1
    Join Date
    Feb 2015
    Location
    Pakistan
    Age
    40
    Posts
    48
    Rep Power
    0

    Calculation of Refrigeration capacity



    Hi

    I am new to refrigeration and looking to build up a cold room. I have different people saying different capacity and needs clarification to how much KW refrigeration capacity would be required for below:

    Length 10.9728 meter
    Width 12.192 meter
    Height 7.3152 meter

    Fruits to be stored: 205 Tons
    Insulation: 100 mm Polystyrene

    Fruits entering temperature 15 C
    Target temperature 04 C
    Time to cool down: 24 hours

    Refrigerant to be used: R717

    Would appreciate if someone can help me with this.

    Regards
    Salman Khan



  2. #2
    Join Date
    Apr 2011
    Location
    TURKEY
    Age
    37
    Posts
    7
    Rep Power
    0

    Re: Calculation of Refrigeration capacity

    approx 62 kW

  3. #3
    Join Date
    Feb 2015
    Location
    Pakistan
    Age
    40
    Posts
    48
    Rep Power
    0

    Re: Calculation of Refrigeration capacity

    Hi

    Many thanks for kind email.

    I would appreciate if you can let me know how you calculate it

    Regards
    Saleem Khan

  4. #4
    Join Date
    Mar 2009
    Location
    U.S.A.
    Posts
    300
    Rep Power
    12

    Re: Calculation of Refrigeration capacity

    Presuming this is a load-unload type of process, you might question your 24-hours available to cool but....

    Total Heat to be Removed: Q

    Q=m Cp Delta-T where
    m is the mass of product
    Delta-T is the temperature change you are trying to effect (11-deg. in this case...)
    Cp is the sensible heat of the product: you only said fruit, the ASHRAE refrigeration manual has 44 Cp values for fruit: For fresh fruit, they basically fall between .82 and .91.

    You then divide that number by the time (24-hours) to get a rate at which heat needs to be removed....

    That is the big portion of the load...The enclosure load includes some transmission through the walls, maybe a few percent of the total; the heat associated with the internal equipment, which may simply be lighting, the heat and moisture yielded by the occupants...All that amounts to not a lot; the big item associated with the enclosure is the air exchange rate which is dependent on the size of the doors and how long it is open; and the condition (temperature and humidity) of the entering air. With a small enclosure and a big door in a wet climate, this may well effect your pull down rate because the finned coil is going to frost pretty quickly should there be a lot of air exchange and of course when its being defrosted its not refrigerating....

    So get your product heat identified, then consider how you are going to load and unload that 205 tons...At that scale of enclosure, with that much product turnover, you are probably looking at 6 to 8 air changes a day...maybe more.

    And I anticipate its higher than the 68 KW.

Tags for this Thread

Posting Permissions

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