Results 1 to 4 of 4
  1. #1
    Join Date
    Jun 2008
    Location
    singapore
    Age
    41
    Posts
    34
    Rep Power
    0

    EXV and Compressor Variable speed drive



    Hi,

    can someone please explain on how EXV and Compressor VSD work together? Will EXV send signals to the compressor VSD to regulate the flow rate?

    please advice.

    Thanks
    -jp



  2. #2
    Join Date
    Mar 2008
    Location
    England
    Age
    34
    Posts
    63
    Rep Power
    17

    Re: EXV and Compressor Variable speed drive

    Hi JP,

    From my experience, the required cooling load will be worked out by the main control unit for the chiller/refrigeration machine, from the leaving water/air temperature and the time it took to reduce the temperature.
    The control unit will then send a signal to both the compressor and EXV to regulate the refrigerant flow and pressure difference to match the required cooling capacity; if possible.

    I hope this helps, though it is a bit vague. I have done a lot of work with Turbocor units, and they generally work on this principle.

    Thanks,

    Bash

  3. #3
    Join Date
    May 2006
    Location
    India
    Age
    74
    Posts
    400
    Rep Power
    18

    Re: EXV and Compressor Variable speed drive

    The vsd needs a signal to change the frequency of vsd . The signal is either from a pressure transducer mounted on the casing of compressor . In other words, the suction pressure change due to fall in load is sensed by pressure transducer & it is converted in a 4 to 20 milliamp signal .the signal changes the frequency & hence the speed .
    You can install a temperature transmitter to achieve the frequency change .the exv will respond on the pressure differential across it`s port

  4. #4
    Join Date
    Mar 2006
    Location
    Merate (LC) - Italy
    Age
    52
    Posts
    2,554
    Rep Power
    24

    Re: EXV and Compressor Variable speed drive

    EXV and VSD do not necessarily know what they are doing one another. They are on different control loops. EXV is regulated on superheating, VSD on heat load.

Posting Permissions

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