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  1. #1
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    Extra liquid pump in DX system



    Hi all.
    I have came with idea to make a DX system with a extra pomp after liquid reciver.
    What i want to do is to get with condensing temperature to a very low value even by the cost of no subcooling. This will make a compressor to have a lighter work (less power consuption, more cooling power). But TXV dont like small pressure different between suction and discharg line. So i'm thinking of putting a pomp with which i will rise the pressure of the liquid between pump and TXV also giving it some subcooling .

    Sorry for my english, i'm from Poland
    Any comments if someone have allready try such a thing? is it possible to work fine? does it have any sens?

    Thanks for all opinions!



  2. #2
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    Re: Extra liquid pump in DX system

    Hi Crocens,

    I think this might be what you are after.

    http://www.hysave.com/category/products/lpa-pumps/

  3. #3
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    Re: Extra liquid pump in DX system

    yes, this is exacly what i need. THANKS. But i have another problem with taking right pump... does anybody know how to choose the right size of such a pomp? Are there any equations about how much pressure i will gain after using such pomp?

  4. #4
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    Re: Extra liquid pump in DX system

    Pump curves will give you pressures and capacities.
    Lowering condensing pressure is good energy saving measure. However, some other issues can arise. Hot gas defrosting, oil carry over...

  5. #5
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    Dec 2007
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    Re: Extra liquid pump in DX system

    crocens,
    What pressure do you want to achieve & what refrigerant are you using?

    You may be able to use a Hermetic liquid pump if Hysave is not big enough.

  6. #6
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    Re: Extra liquid pump in DX system

    Hi RANGER1,
    I have R-404a, 4 compressors - each 25,57 m3/h, evaporating temp -10*C.
    Pressure at inlet to the pomp will be floating from 9 to 18bars depending on weather. I want after the pomp about 16bars.

  7. #7
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    Re: Extra liquid pump in DX system

    crocens,
    Maybe you should try Hysave & see what they can recommend you anything.

    I think Danfoss electronic expansion valves would be best option.

    They can control over a much bigger range, I think down to 10%.

    Correct selection for low & high discharge pressures should be achievable.

    This is more accurate than conventional TX valves.

    How many valves do you have?

  8. #8
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    Re: Extra liquid pump in DX system

    I have 10 evaporators, i thought that this pomp will give me constant 16bar at inlet of EVs. But i will concider puting EEV for another reasons. I have allready send a question to Hysave, we will see what they think about that.

    Thanks for replay.
    Marcin
    Last edited by crocens; 06-06-2011 at 04:54 PM.

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