Results 1 to 7 of 7

Thread: cooling volume

  1. #1
    solgen's Avatar
    solgen Guest

    cooling volume



    Hi,

    I'm new to this forum and not a refrigeration engineer but would like to ask a question which I suspect hasn't got a simple answer!

    A warehouse is used to store food at a cooled temperature of 10 degrees C and the electricity consumption for refrigeration is 900,000kWhrs per year. The height of the building is twice that it needs to be and so approximately half the volume of the building is unecessarily chilled. If a false ceiling was introduced the volume of cooling could be halved.

    Would it be fair to say the energy consumption to chill this area could be half?

    Is there a formula or rule of thumb calculation that can be used to work out the typical energy requirement of the scenario I've described?

    Thanks



  2. #2
    Join Date
    Sep 2003
    Location
    ISRAEL
    Age
    65
    Posts
    4,107
    Rep Power
    37

    Re: cooling volume

    It will not cut it by half. if a new insulated ceiling in the proper height will be installed, it will help.

    Best is to get the services of a consultant engineer to have it checked out.

    A cooled hall in the entrance, can save on warm humid air from entering.

  3. #3
    Join Date
    Oct 2008
    Location
    newbury
    Age
    56
    Posts
    1,349
    Rep Power
    29

    Re: cooling volume

    Quote Originally Posted by chemi-cool View Post
    It will not cut it by half. if a new insulated ceiling in the proper height will be installed, it will help.

    Best is to get the services of a consultant engineer to have it checked out.

    A cooled hall in the entrance, can save on warm humid air from entering.
    doesn't that just make it a bigger fridge?

  4. #4
    Join Date
    Sep 2003
    Location
    ISRAEL
    Age
    65
    Posts
    4,107
    Rep Power
    37

    Re: cooling volume

    No, in most big cold stores where they have high traffic, it is common thing to have like a cooled entrance where products gets colder and drier than out side conditions and after a while, they moved in.its more like a cooled corridor.

  5. #5
    Join Date
    Sep 2007
    Location
    Somerset
    Age
    63
    Posts
    4,502
    Rep Power
    38

    Re: cooling volume

    If you halve the volume then you do reduce (although the chilled product volume is not being reduced!) the initial amount of energy needed to bring that area down to temperature.
    But as a result you will also vastly increase the necessary reaction rate of the cooling equipment to the ingress of heat. Introduced as a direct result of the "traffic".
    Maintaining a room temperature is easier and cheaper the smaller the fluctuations of temperature within!

    A smaller area is not necessarily cheaper to maintain, think of the volume as a form of buffer tank!
    Yes smaller areas are easier to control but are also much more susceptible to temperature fluctuations.

    I have tried to explain using simple terminology hopefully someone else can elaborate further?
    In summary halving the size does not halve your energy consumption and in fact could increase it!
    Chemi's point is to reduce the external temp influence on the chilled area.

    Things like stock rotation frequencies and their temp on being stored in the warehouse also have huge effects.
    Even the type of product being stored has huge ramifications.
    I forget the exact formula but it's something like for every 1 degree rise there is a 10% rise in energy consumption!
    Think what reducing the chilled volume would do to the amount the temperature rises?


    Grizzly
    Last edited by Grizzly; 28-09-2012 at 11:42 PM.

  6. #6
    solgen's Avatar
    solgen Guest

    Re: cooling volume

    Thank you for your advice - I will indeed consult an expert but just wanted to understand some basic theories first. The fact that the warehouse in question has several loading bays which are open to the elements does suggest that if the height of the building was lowered, the cooling equipment would have to react a lot quicker to the temperature changes caused by external temperature ingress. I would appreciate if someone could add any further info. to this and if anyone can point me at where the 1 degree rise in temp would result in 10% rise in energy consumption. Thank you

  7. #7
    Join Date
    Dec 2010
    Location
    ZA
    Posts
    157
    Rep Power
    9

    Re: cooling volume

    Size really has a small effect on your power use. Reducing heat input by having enclosed bays, staging areas with barrier curtains and changing the forklifts inside to electric will have a bigger effect on your power bill. Training staff not to leave the doors open unnecessarily and placing multiple air curtains to those that have to be open will help as well. Checking for air leaking in as well will help, as well as having a reflective roof that keeps the top cooler helps.

Posting Permissions

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