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  1. #1
    If I have a conditioned space of 25 degrees F and an outside temp of 30 Degrees F with a 4:1 compression ratio; What would the compression ratio be if outside air temp climbed to 65 degrees? I'm using R-22

  2. #2
    Join Date
    Nov 2001
    Location
    east kansas
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    3.963743918 to 1

    25 degrees-10 degrees = 15 degree = 52.405 absolute.

    65 degrees + 30 degrees= 95 degrees = 207.72 absolute.

    207.72 / 520.405 = 3.963743918 to 1

    I guess.
    Beware of advice given by some guy on the Internet.

  3. #3
    Join Date
    Nov 2001
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    east kansas
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    But I'm figuring 2.219444709 to one for your example.

    I guess.
    Beware of advice given by some guy on the Internet.

  4. #4
    Join Date
    Jan 2006
    Posts
    32

    The compression ratio will remain the same

    Compression ratio is calculated by dividing the high side pressure in psia by the low side pressure in psia. Since you have a box temperature of 25 degrees, assuming a 10 degree delta-t between the box temperature and the evaporator saturation temperature, you have a 15 degree coil, which equates to a 38 psig low side pressure. conveting this to an absolute pressure give you about 53 psia.

    Since you said you had a 4:1 compression ratio, your high side pressure in psia is 210.8 psia, or about 196 psig.

    Since your outside ambient is 30 degrees, you have some type of head pressure control that is designed to maintain the high side pressure at 196 psig.

    So, if the outside ambient temperature rises to 65 degrees, the system will still maintain 196 psig and your compression ratio will remain the same.

    Hope this helps.

    P.S. Why do you ask?

  5. #5
    Join Date
    Nov 2001
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    east kansas
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    Good point about the head pressure control.

    Beware of advice given by some guy on the Internet.

  6. #6
    Join Date
    Jan 2006
    Posts
    32

    Thanks Lynn

    Thanks.

  7. #7
    Thanks. This was a test question that I was researching

  8. #8
    Join Date
    Jan 2006
    Posts
    32

    Consider Yourself....

    RESEARCHED!

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