Page 1 of 2 12 LastLast
Results 1 to 13 of 23

Thread: surging

  1. #1
    Join Date
    Oct 2008
    Location
    uae
    Posts
    1

    surging

    what is mean by surging?Iwant an explenation about surging on water cooled centrifugal chiller.

  2. #2
    Join Date
    Feb 2008
    Location
    Waffleville
    Posts
    10,339
    it means you posted a technical question in the wrong area of the forum

    try the commercial guys down the forum a lil ways
    If Guns Kill People, Do Pencils Misspell Words?

    http://www.youtube.com/watch?v=An2a1...eature=related

    Before we work on artificial intelligence why don't we do something about natural stupidity?

  3. #3
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,003
    Every centrifugal chiller has a design "lift" . Lift is the difference in operating pressure between the condenser and the evaporater . If you exceed the lift the chiller will surge . During a surge the impellor/s are unable to overcome the pressure difference and the refrigerant rushes backwards through the impellor and in some cases stalls the motor .
    Surge is usually caused by too high tower water temp or in low pressure chillers by air or non condensables in the refrigerant side of the chiller (because of leaks )causing high head pressure but you can also have a low end surge which is low load .
    Try typing surge into the keyword search and you probably find lots of threads to help you .
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  4. #4
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,003
    Maybe " Lord Edward J " can come on again and give us his sound engineering principles and advice as to what surge is again ????????
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  5. #5
    Join Date
    Oct 2008
    Location
    Central Oregon
    Posts
    184
    It's "surfing" with a typo.

  6. #6
    Join Date
    Mar 2003
    Posts
    7,321
    Centrifs are not positive displacement type compressors and have limited ability to overcome pressure after the wheel ( in the condenser). The compressor uses centrifugal force for compression of vapor. The vapor enters the eye of the wheel, and is thrown outward by the wheel toward the volute and directed into the condenser. There is only soo much of this centrifical force available for a given wheel(lift). When condenser pressure is too high, as in the high entering water temp example above, the discharge gas actually flows backwords on the wheel as a surge. The wheel simply cannot overcome condensing pressure. kinda simplistic reply, but paints a picture.

  7. #7
    Join Date
    Sep 2004
    Posts
    175
    Quote Originally Posted by jakson mathew View Post
    what is mean by surging?Iwant an explenation about surging on water cooled centrifugal chiller.
    It usually means it's screaming & moaning like a raped elephant

  8. #8
    Join Date
    May 2006
    Location
    N.E. IA
    Posts
    512
    [QUOTE=graham;2019246] in some cases stalls the motor .


    "As in, the motor stops turning?????????
    "Wheel" mechanics work on "Wheel" chillers

  9. #9
    Join Date
    Sep 2004
    Location
    crossville
    Posts
    608
    [QUOTE=referteacher;2020288]
    Quote Originally Posted by graham View Post
    in some cases stalls the motor .


    "As in, the motor stops turning?????????
    more it slows the motor speed down to the point the motor will trip overcurrent protectors then its a shutdown and wait to restart cycle
    If you cant cool it
    HEAT THE Hello out of it

  10. #10
    Join Date
    Jan 2005
    Posts
    604

    surging and amp draw

    As gas flows backwards over impeller, amps drop off. When the lift gets to where impeller can do it's work again, it grabs all the gas it can and amps go way up (may be higher than full load amps).

  11. #11
    Join Date
    Sep 2008
    Location
    Cedar Rapids, IA
    Posts
    486
    Quote Originally Posted by jsherhvac View Post
    It usually means it's screaming & moaning like a raped elephant
    Now that is the most technically accurate description I've heard!

    Needless to say surging is not good for multiple components in the machine like bearings for instance.

  12. #12
    Join Date
    Sep 2002
    Posts
    12,195

    How can I avoid surging ?

    If surging is basically; 'exceeding the compression ratio of the compressor' - how can it be avoided? Most especially under low load conditions?

    And doesn't part-load operation accent the issue? I'n no centrifugal guy but if the load is low, the unit is unloaded, and the impeller is hardly pumping anyway, it seems like the two curves of heat load and compressor unload pumping ability have to cross at some point.

    What is the way to mnimize the effect? False load the chilled water loop with boiler water? Lower head pressure to follow the chilled water load down?

    Why wouldn't the controls be set up to cycle the machine off before surging occurs?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  13. #13
    Join Date
    May 2008
    Location
    Jax Fl.
    Posts
    1,943
    Many years ago, I took a new apprentice into a mechanical room where an old sidewinder was running and showed him the control panel that was tight against a wall. I then explained how these machine were know to make a loud noise and then explode like a 2000 pound bomb, while all the time turning the load limit percentage lower and lower.
    When it surged it scared him senseless.....That was as much fun as sending them into the air box and turning off the lights just as you started the huge fan which filled the room with belt squealing/rubber smoke...

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image