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  1. #1
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    ABCs of Screw compressors and refrigeration



    Dear All,

    I need assistance with the following information:

    I am looking after a cold store with 4 screw type ammonia compressors - 2 for chiller / 2 for freezer ops.

    I will start by the basics - can any one tell me some good reading on these systems?

    I need to start by learning the basic refrigeration principles - go ahead and dive into the current system and also understand what terms like
    Capacity: 325kW at SST -35 dC means
    bKW: 175kW at SST -35 dC means,

    Difference between single stage screw and compound two stage screw.

    Looking forward to your reply?

    Also, what is the minimum temperature we can achieve using this system? what data do I need to calculate total load for the room!



  2. #2
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    Re: ABCs of Screw compressors and refrigeration

    Dear Haris

    welcome to RE forums...

    Quote Originally Posted by haris View Post
    Dear All,

    I need assistance with the following information:

    I am looking after a cold store with 4 screw type ammonia compressors - 2 for chiller / 2 for freezer ops.

    I will start by the basics - can any one tell me some good reading on these systems?

    I need to start by learning the basic refrigeration principles - go ahead and dive into the current system and also understand what terms like
    Capacity: 325kW at SST -35 dC means
    bKW: 175kW at SST -35 dC means,


    Difference between single stage screw and compound two stage screw.

    Looking forward to your reply?

    Also, what is the minimum temperature we can achieve using this system? what data do I need to calculate total load for the room!
    The best advice to you is to search RE forums .... like http://www.refrigeration-engineer.co...geration-Books

    where you will find a lot of links to some good literature... then http://www.refrigeration-engineer.co...?12-Industrial

    of course in each forum you can find some good information depending what are you looking for ...

    To answer your questions is not easy ... you need to download some literature .... but for beginning ...

    Capacity of 325kW at Saturated Suction Temperature of -35*C

    http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cts=1331285410502&sqi=2&ved=0CCcQFjAA&url=http%3A%2F%2Fstud ent.fnu.ac.fj%3A82%2FRefrigeration %26 Air Conditioning%2FRefrigeration Basicswte.ppt&ei=lM1ZT6npLoet8gOixqSGDw&usg=AFQjCNF_bzVf0Mi041p0FgmGhf4PCa_Q3Q&sig2=GVeA9xn6_YGPD92W Fu0qSA

    http://www.google.com/url?sa=t&rct=j...SPlqhuiFJ36Byw

    single stage and compound compressor ...

    single means that within one compressor all pistons or pair of screws are working in one stage .... i.e. suction at -10*C and condensing at 30*C

    compound compressor means within the same compressor we have usually two stages .... a few (usually 4 or 8) pistons are working in a low or first stage at low pressure i.e. suction at -45*C and condensing at -10*C and a few pistons (usually 2 or 4) pistons are working in a high or second stage i.e. suction at -10*C and condensing at 30*C ... within compound screw compressor we have 2 pair of rotors .... bigger pair for low or first stage and smaller pair for high or second stage ..

    http://www.mayekawa.com/products/compressors/

    There are some compressors, usually piston type, with more stages for some special purposes ....

    Hope this is of some help to you.

    Best regards, Josip

    It's impossible to make anything foolproof because fools are so ingenious...

    Don't ever underestimate the power of stupid people when they are in large groups.

    Please, don't teach me how to be stupid....
    No job is as important as to jeopardize the safety of you or those that you work with.

  3. #3
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    Re: ABCs of Screw compressors and refrigeration

    The .ppt seems excellent - very basic and easy to understand.. will give more time to all the readings and then get back to you with more questions.. might bother you a few more times sorry about the inconvenience

  4. #4
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    Re: ABCs of Screw compressors and refrigeration

    Hi, Haris

    Quote Originally Posted by haris View Post
    The .ppt seems excellent - very basic and easy to understand.. will give more time to all the readings and then get back to you with more questions.. might bother you a few more times sorry about the inconvenience
    Fortunately, nowdays You can find almost all on internet ... just need some time for surfing and asking the right question ... if you cannot find what you need come back .... here we have a lot of members with fabulous knowledge .... so, if not me, don't worry someone else will try to help you welcome....


    Best regards, Josip

    It's impossible to make anything foolproof because fools are so ingenious...

    Don't ever underestimate the power of stupid people when they are in large groups.

    Please, don't teach me how to be stupid....
    No job is as important as to jeopardize the safety of you or those that you work with.

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