Results 1 to 7 of 7
  1. #1
    Join Date
    Dec 2006
    Location
    Indonesia
    Age
    74
    Posts
    37
    Rep Power
    0

    30°C to 20°C in one hour?



    Hi all, greetings from Indonesia again...
    I need to calculate how much compressor power needed for this:

    I need to cool 10.000 liter (roughly 2,641 gallon) of water from 30°C (86°F) down to 20°C (68°F) within one hour.

    I found this formula:

    BTU = gallons x temperature change x 8.33

    The result for my numbers would be... 395,991 BTU or 155 HP.
    Is that number seems realistic? It seems so high, or is there a mistake?

    Thank you for all your input, really appreciate it.

    Regards,
    Yahya.



  2. #2
    Join Date
    Aug 2010
    Location
    UK
    Posts
    110
    Rep Power
    14

    Re: 30°C to 20°C in one hour?

    10000l/hour = 2.8l/sec
    30deg - 20deg = 10deg
    specific heat capacity of water = 4.2

    2.8 x 10 x 4.2 = 117.6kW of refrigerating capacity.

    I don't really know what BTU's and Gallons are?

  3. #3
    Join Date
    Sep 2012
    Location
    India
    Posts
    77
    Rep Power
    13

    Re: 30°C to 20°C in one hour?

    For getting 120 kW cooling considering 10 C evaporating and 40 condensing temperature refrigeration compressor will need around 20 to 25 kW power input depending upon which refrigerant is used.

  4. #4
    Join Date
    Dec 2006
    Location
    Indonesia
    Age
    74
    Posts
    37
    Rep Power
    0

    Re: 30°C to 20°C in one hour?

    Thank you so much for all the replies, really helps.

  5. #5
    Join Date
    Dec 2006
    Location
    Indonesia
    Age
    74
    Posts
    37
    Rep Power
    0

    Re: 30°C to 20°C in one hour?

    Quote Originally Posted by sandybapat View Post
    For getting 120 kW cooling considering 10 C evaporating and 40 condensing temperature refrigeration compressor will need around 20 to 25 kW power input depending upon which refrigerant is used.
    May I know how did you came up with the number 20 to 25 kW power input? Thanks.

  6. #6
    Join Date
    Sep 2009
    Location
    Iran
    Age
    66
    Posts
    672
    Blog Entries
    1
    Rep Power
    19

    Re: 30°C to 20°C in one hour?

    also
    Q= MC (t2-t1)
    M=10000 Kg/ h
    C=1 for water

    Q= 10000 * 1(30-20)
    Q= 100000 cal/h

    1 Kw = 860 cal

    to get that you need to add %10 for safety and then you have to choose your Comp.

    your evaporator temp. about 10 c ( out let temp. - delta T )

    your condenser temp. about (ambient temp. + 10)

  7. #7
    Join Date
    Sep 2012
    Location
    India
    Posts
    77
    Rep Power
    13

    Re: 30°C to 20°C in one hour?

    As mbc has explained I tried to select compressor 120 kW capacity with 10 deg C evaporation temp and 40 deg C condensing temperature and I got the power consumed by compressor.

Posting Permissions

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