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  1. #1

    Heeeeeeeeeeeeeeeeeeeelp

    Heeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeelp.
    I have a refrigeration project and I don't know anything.
    I need to ask someone who knows a few questions. The presentation is due one Friday.

    Let's say I found the required load and it is = 40 kW
    Cold store condition = 2 degree C
    Product is apples
    Dry bulb temp = 36 degree C

    How do I choose:
    1. Refrigerant
    2. Evaporating temperature
    3. Refrigerant temperature (or is it the same as 2.)
    4. Condensing temperature
    5. Compressor power
    6. Different temperature differences in the cycle
    7. Equipment selection

    Keep in mind this is a small college project. The teacher obviously doesn't know anything, so I'll accept an help.

    thank you

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,120
    Moved to Refrigeration and Ice Making forum
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    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    Quote Originally Posted by elieprolb View Post
    I have a refrigeration project and I don't know anything.....

    .......The teacher obviously doesn't know anything.....
    Sounds like you're wasting your parents tuition money.

  4. #4
    Quote Originally Posted by gary_g View Post
    Sounds like you're wasting your parents tuition money.
    No
    It's a public free college...
    I would have enjoyed your help more than your non-funny jokes

  5. #5
    Join Date
    Jan 2004
    Posts
    933
    I would open some books like my copeland manual and to some research, why should we do your Homework for you?
    Still learning opinions welcome.

  6. #6
    Quote Originally Posted by 2story View Post
    I would open some books like my copeland manual and to some research, why should we do your Homework for you?
    No. I'm actually reading two books but I'm not understanding everything. I don't need you to make my homework, I need a few hints if I'm allowed to call them so. I need catalogs for equipment selection, there is none in my books and the teacher haven't provided any.
    I want to know the temperature of evaporation and condensation of different refrigerants so I can choose one. I also want to know where do I use the 40 kW load I calculated on my OWN and haven't asked YOU to do it !!!!!!!!!!!
    Thanks for nothing

  7. #7
    Join Date
    Jul 2008
    Location
    hearth planet
    Posts
    87
    I think it would be interesting to how you got that big number and can΄t find a refrigerant type

  8. #8
    Join Date
    Jun 2004
    Location
    Howell, Michigan
    Posts
    16,176
    Quote Originally Posted by elieprolb View Post
    No. I'm actually reading two books but I'm not understanding everything. I don't need you to make my homework, I need a few hints if I'm allowed to call them so. I need catalogs for equipment selection, there is none in my books and the teacher haven't provided any.
    I want to know the temperature of evaporation and condensation of different refrigerants so I can choose one. I also want to know where do I use the 40 kW load I calculated on my OWN and haven't asked YOU to do it !!!!!!!!!!!
    Thanks for nothing


    I think your skin needs to be a little thicker. You roll in here asking for help, the guys around here are testing you and you post like that. Your chances of getting help are going down hill fast.

    So, now tell us something, are you a student at a college studying HVAC, is this a hypothetical question or do you really have a load of apples that need to be refrigerated?

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,120
    Hints:

    When you did your load calc, you had to have a box temp. Your refrigerant should not have the compressor operating in a vacumm to attain that temp.

    Virtually all manufacturers have catologs online that you can download. And see what their units BTU capacities are at the evaporator temp you need.

    A single evaporator doesn't work in every appliaction.

    Do you know if your box temp requires a defrost cycle.

    Did you do your load calc based on an hour. Or based on a 24 hour day.
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  10. #10
    Join Date
    Feb 2008
    Location
    California
    Posts
    2,066
    how can you ask a question about system design and not know the bare bone basics?

    You are trying to run before you can walk.

    and you come off as an ignorant prick.

  11. #11
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,374
    Heatcraft refrigeration has an excellent manual for load calculation and equipment selection:

    http://www.heatcraftrpd.com/resource...H-ENGM0408.pdf

    Choosing which refrigerant to use calls for a bit of knowledge of economics, environmental concerns and of course...experience. I suggest going with R404A as it's likely the best all around refrigerants for commercial refrigeration systems available today.

    If you need to select specific equipment, Heatcraft has all the catalogs you'll need. Here's a condensed catalog form Bohn (one of Heatcraft's product lines):

    http://www.heatcraftrpd.com/resource...BN-CC-1008.pdf

    Good luck on your project.

  12. #12
    Join Date
    Mar 2008
    Location
    Banana Republic,Florida
    Posts
    400
    like ice said theres so many sites out there that can get you very close to what you are looking for also emerson has an option called Product selection software check it out also good luck
    Mastic its whats for dinner!

  13. #13
    Join Date
    May 2008
    Location
    S.E.Virginia
    Posts
    87
    Just about every equipment manufacturer has the info you need be it software or worksheets go to their website. Most the stuff is free to download.. You should spend your time at their sites and you will learn a great deal without having to ask anyone and put up with abuse for wanting the answers given to you. No one is really doing you any favors by giving the answers. Learning is a process that happens with effort and desire......usually in equal measures....good luck

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