Results 1 to 8 of 8
  1. #1

    VFD for chiller necessary along with pumps with VFDs?

    Hey friends,
    Can anyone please clear my doubts.
    Suppose we use chilled water pumps along with VFDs, is it still necessary that the chiller too must be selected with VFDs?
    What differences will it make if i use VFDs for both the equipments?
    Thanks in advance.

  2. #2
    Join Date
    Jun 2013
    Location
    Austin, TX
    Posts
    455
    While it would be best to have both VFD driven, it's not absolutely required. I would actually suggest VFDing the chiller first, but that also takes a large and expensive VFD. VFDing the water pumps is cheaper, but you'll only see savings where the demand for chilled water varies a lot.

  3. #3
    What effects will it have if VFD is provided only for the chillers and not pump and vice versa..??

  4. #4
    Join Date
    Feb 2004
    Location
    New Mexico
    Posts
    5,355
    The advantage for VFD's on pumps is all the pumps brake horse power in the chiller circuit will be converted to heat at aprox 1/5 ton per HP. While pumps add BTU's to a heat circuit they take from a cooling circuit.
    Like Mike said above you'd need to do some math to see if pump vfd's would be active enough to be cost effective. Most systems have enough range so vfd's are a good idea.
    There are other ways to cut power on some chillers with unloaders. Way cheaper than large vfd's.
    The problem with the laws of thermodynamics is you can't win, you can't even break even.
    Tracers work both ways.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,824
    Moved to Open chillers forum.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Jun 2013
    Location
    NORTHERN
    Posts
    931
    Variable compressors such as with HVAC HIGH-SPEED cooling 30 EER's and 42 in blended lower speeds if that is like 75 percent of the time of the low to medium speeds


    You may know small plus larger then both on for a third stage
    Efficiently works
    many variable operations for any motors blowers pumps or compressors
    And if it fits a pump at each one of distributed loads of the chiller requirements can have 10 single pumps say at 10 locations duplicating a variable drive system

    As geothermal chillers

  7. #7
    Join Date
    Jun 2013
    Location
    NORTHERN
    Posts
    931
    OEM pump rack designers can help with picking two pumps in series to operate as a three-stage system

  8. #8
    Join Date
    Jun 2013
    Location
    NORTHERN
    Posts
    931
    As geothermal chillers refers to multiple heat pumps have had the OEM built inside with circulator built inside with a check valve

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

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event