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  1. #1
    Join Date
    Sep 2011
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    BAJA AND CALIFORNIA
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    90

    VFD IN A CVHE CHILLER FOR ALL PRO

    HELLO PROFESIONAL CHILLERS EXPERT WITH EXPERIENCE IN TRANE CENTRIFUGALS NEED SOME HELP AND SHARE EXPERIENCE :

    ANY ONE HAVE EXPERIENCE INSTALLING A VFD IN A CVHE CENTRIFUGAL R-123 AND IF REALLY WORTH TO INSTALL THE VFD. VINTAGE OF THE UNIT 1998
    THE UNIT IS STILL IN VERY GOOD SHAPE

    REGARDS

    OSCAR

  2. #2
    Join Date
    Mar 2007
    Posts
    3,103
    I could be wrong, but It's my understanding that older machines without a refrigerant pump won't support a refrigerant cooled AFD. An air-cooled drive would work, but it'd be better if the controls were >= CH530. I've never seen a UCP2 machine with a drive.
    "There is no greater inequality than the equal treatment of unequals."

    -Thomas Jefferson

  3. #3
    Join Date
    Oct 2011
    Location
    La.
    Posts
    279
    It depends on the original selection of the machine. If it was chosen too close to its surge line then the drive will run all of the time in higher frequencies. You will not save money there. Sorry to say this, but you need to get Trane in on this; as they can tell you how much the unit is capable of turning down and you will also need a control upgrade, and you still have a refrigerant that is going out of style. You could probably replace the chiller for less. Good luck.

  4. #4
    Join Date
    Sep 2011
    Location
    BAJA AND CALIFORNIA
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    90
    my concern is more about the oil and motor cooling if we low the speed of the motor the machine keep the same level of lubrication and the motor cooling.
    regarding to the surge line and lift i didnt see any problem , but your opinion is very valuable i will contact local trane guys to see they opinion .

    also i want share document from trane but didnt see how to attach here

  5. #5
    Join Date
    Oct 2011
    Location
    La.
    Posts
    279
    Being a low pressure machine and having a fixed orfice are going to be the big hurdles as you are already questioning. The savings will not be there because of this. A drive saves you money by using cooling tower relief(as in low water temp to reduce lift) The problem with a fixed orfice is you cannot lower the water to cold because of refrigerant mass flow issues. A trane also does not like cold condenser water to start with, they will loss oil with to cold condenser water. Like I said, it just does not make sense for the money. Buy a new chiller of love the one your with.

  6. #6
    Join Date
    Sep 2011
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    BAJA AND CALIFORNIA
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    90
    thanks again for your advise

  7. #7
    Join Date
    Mar 2007
    Posts
    3,103
    Oil won't be a problem. And as long as you maintain enough differential pressure in the system, motor cooling won't be a problem, either.

    I've seen lots of low pressure Trane chillers running the entering condenser water temps down into the high 50s/low 60s without oil loss problems. As long as you have enough "water lift", it is ok. If the machine hasn't surged like crazy for years and years and the seals are good, oil loss/return is a non issue. Same for the fixed orifices. We have plenty of CVHE/F machines out there with drives on them, and they all run just fine with fixed orifices.

    R-123 is going to be available for a long time to come. These chillers could run for decades. A drive could definitely save some money, but like spinning wheel said, you're probably looking at a controls upgrade, too.
    Last edited by Tech Rob; 01-19-2012 at 09:11 PM.
    "There is no greater inequality than the equal treatment of unequals."

    -Thomas Jefferson

  8. #8
    Join Date
    Sep 2011
    Location
    BAJA AND CALIFORNIA
    Posts
    90
    Rob apreciate your support and im agree with you also .
    thanks for quick response and profesional opinion
    regards

    oscar

  9. #9
    Join Date
    Sep 2007
    Location
    Bay Area California
    Posts
    321
    i am with Tech Rob on this...
    i have installed numerous drives on CVHE's... UCPII, CH530, Adaptiview and other packages i will get yelled at for... They all work great!
    Yes there are some things to think about but, but the set up can render a great result. Keep in mind, just coming off of 60 hz is the low hanging fruit as savings go... Yes it would be nice to run 30 Hz but usually i set my min speed at 48 hz and if conditions are favorable i will go down from there...
    There are some things that should be considered with the placement of the oil educators and I'm always looking to maintain a minimum lift on the machine which is accomplished thru condenser water pump VFD and coupled with some tower fan control logic. If there is problem with motor cooling the first place you will see it will be the rear bearing oil return. Shaft grounding and harmonics should be considered and planned for.
    This stuff is not rocket science and makes a huge difference in the overall operation of the plant opening up all kinds of opportunities for pump/ Fan savings...

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