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  1. #1
    Join Date
    Mar 2016
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    Subcooling and low ambient temperature

    Will subcooling increase or decrease if ambient temperature drops and if so why?

  2. #2
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    Aug 2011
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    Good question. Are you referring to charging a heat pump in the cold weather?

  3. #3
    Join Date
    Mar 2016
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    Thread Starter
    chiller operating in low ambient

  4. #4
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    Dec 2014
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    New Mexico
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    With proper condenser fan control it will stay pretty consistent.
    Water cooled with proper tower control should stay consistent as well.


    Sent from my iPhone using Tapatalk

  5. #5
    Join Date
    May 2012
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    California
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    Without cond fan control just constant fan you would stack ref in cond subcooling would increase

    Sent from my SM-G900V using Tapatalk

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  7. #6
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    Jan 2017
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    Tyler, Texas
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    Agreed, non modulated fans would be able to subcool refrigerant to the point of making condenser stack the refrigerant. This can cause the evaporator to be starved and raise superheat. But modulated fans should eliminate issue or a HPR valve (head master).

    Sent from my SAMSUNG-SM-G890A using Tapatalk

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  9. #7
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    Feb 2008
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    [QUOTE=James Holden;24377211]Agreed, non modulated fans would be able to subcool refrigerant to the point of making condenser stack the refrigerant. This can cause the evaporator to be starved and raise superheat. But modulated fans should eliminate issue or a HPR valve (head master).

    Sent from my SAMSUNG-SM-G890A using Tapatalk[/QUOT

    will high subcooling cause to increase superheat? how?

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  11. #8
    Join Date
    Mar 2005
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    exactly
    Keep it simple to keep it cool!

  12. #9
    Join Date
    Jan 2017
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    Tyler, Texas
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    In low ambient conditions the reason the subcooling rises so much is because it starts to stack in the condenser. The reason for this is refrigerant is attracted to the coldest place in the system. During the winter the ambient conditions get below the temperature at the evaporator causing the refrigerant to naturally want to migrate there. Now in this case with a chiller that means water over evaporator is normally 50*f to 55*f and 45*f coming out. So the outdoor temperature would have to get below the water temperature (this applies to air cooled only, if it is water cooled on condenser then its different situation). So when the temperature ambient gets low the refrigerant stacks and looks like a high subcooling and this will result in a high superheat because the refrigerant is not flowing appropriately through the condenser which will begin to starve the evaporator causing high superheat.

    Sent from my SAMSUNG-SM-G890A using Tapatalk

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