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  1. #1
    Join Date
    Mar 2017
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    STAND BY CHILLER REQUIRED OR NOT

    Hey,

    I am working as a client engineer. Please help me regarding is there any other solution other than providing standby chiller for the building.

  2. #2
    Join Date
    Jan 2015
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    Ice storage arrangement, I would go with redundancy first.

    Sent from my SM-G950U using Tapatalk

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  4. #3
    Join Date
    Mar 2017
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    Thread Starter
    Can you please explain what is Ice storage arrangement . Actually I am working in UAE. I did not see this one.

  5. #4
    Join Date
    Jul 2007
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    The Hot South
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    🍿🍿🍿

  6. #5
    Join Date
    Jul 2018
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    Kazakhstan
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    shinozahmed, some info you may find in Trane TRG-TRC019-EN Air Conditioning Clinic. Ice Storage Systems. Google will help you readily.

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  8. #6
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    Mar 2017
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    Thread Starter
    Thank you


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  9. #7
    Join Date
    Nov 2001
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    It is more common to have multiple chillers, all of which are in operation. For example, if you have a building with a 1000 ton design load, you might have two 600-ton chillers so that if one goes down you still have 600 tons. Though, in the UAE you might want to have more reserve.

    If you have a mission-critical facility where you do need full redundancy, that is a different story. Though, even in that case it is generally better to have all of the chillers in operation. In the example above, if you install two 1,000-ton chillers to handle the 1,000-ton load, if they share the load you will use less power than if you ran one and kept the other in reserve.

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  11. #8
    Join Date
    Feb 2016
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    Louisburg Kansas
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    Ice requires cold enough water to freeze the ice. In most facilities it is not economically feasible. Go with back-up.
    No man can be both ignorant and free.
    Thomas Jefferson

  12. #9
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    Jul 2007
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    Quote Originally Posted by coolcoil View Post
    In the example above, if you install two 1,000-ton chillers to handle the 1,000-ton load, if they share the load you will use less power than if you ran one and kept the other in reserve.
    Are you saying if you run 2 1000 ton chillers unloaded to 500 tons each they both use less power than 1 chiller at full load???

  13. #10
    Join Date
    Nov 2001
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    Quote Originally Posted by R123 View Post
    Are you saying if you run 2 1000 ton chillers unloaded to 500 tons each they both use less power than 1 chiller at full load???
    Yes. It’s pretty standard operation. The savings are larger if the chillers are variable speed, but it’s true for fixed-speed as well.

  14. #11
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    Mar 2017
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    Thread Starter
    Thank you..But that one chiller can handle the whole building for the time being of other chiller get repair..for example one day.


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  15. #12
    Join Date
    Aug 2006
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    Quote Originally Posted by coolcoil View Post
    Yes. It’s pretty standard operation. The savings are larger if the chillers are variable speed, but it’s true for fixed-speed as well.
    for variable speed chillers, that is true. 2 unloaded chillers will generally use less energy than an equivalent single chiller fully loaded. variable speed towers and chilled water pumps will increase the savings.

    for fixed speed chillers, the energy consumption will be higher with 2 chillers unloaded than for 1 chiller fully loaded. most fixed speed chillers reach their peak efficiency (lowest kW/ton) around 90-95% RLA. running double the number of chillers (at 45-50% RLA), towers, chilled water and condenser water pumps only increases the energy usage.

    around 90% RLA is typically when an uneducated BAS technician wants to start another chiller thinking that they will lose the load if they don't start another chiller. they usually cause more havoc than they solve. just because it is "pretty standard operation" doesn't mean that it is correct or efficient.

    running fixed speed chillers at a very low RLA often makes them rumble (causing loosening of bolts, excess wear on mating surfaces, etc) and they can't control the leaving chilled water as well since a small change in the refrigerant controlling device makes a large change (relatively speaking) in refrigerant volume pumping. at much higher RLA's, the small changes in the refrigerant controlling device almost makes no difference as the chiller is already nearly maxed out. this provides a smoother leaving chilled water temperature.
    "Right" is not the same as "Wise".

    Don't step on my favorite part of the Constitution just to point out your favorite part.

  16. #13
    Join Date
    Nov 2011
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    Also, sizing of chillers should be based on usage for the load. If you design a system that will have a chiller running nearly fully loaded for a large percentage of run times, you’re better installing a constant speed starter. You can actually lose some efficiency with a speed drive in those scenarios.

    If you have a system designed so that a chiller would not run near fully loaded most of the time, you’ll save energy with a speed drive.

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