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Thread: Refrigeration

  1. #27
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    Quote Originally Posted by timebuilder View Post
    And buy a copy of the book.....
    This is the one I was suggesting....

    Name:  Dick Wirz Book.jpeg
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    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
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  2. #28
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    Refrigeration is the process of cooling a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is rejected at a higher temperature).

  3. #29
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    Why does it need to be rejected at a higher temperature? That doesn't make sense.


    Quote Originally Posted by jackfowler View Post
    Refrigeration is the process of cooling a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is rejected at a higher temperature).
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

    Did you really need the " If you were a real tech " ??

  4. #30
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    Just to be clear, I've worked on a lot of environmental chambers that ran at temps much greater than what the heat was rejected to.

    Then there was that convenience store at 105*F, and once I got that system on line, the refrigeration was rejecting heat to the 60*F San Francisco foggy ambient. Calculate your TD's on that one, and you'll find your suction and discharge pressures nearly the same, relatively speaking.


    Quote Originally Posted by BBeerme View Post
    Why does it need to be rejected at a higher temperature? That doesn't make sense.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

    Did you really need the " If you were a real tech " ??

  5. #31
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    I'm the only one who doesn't understand your point.

  6. #32
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    Quote Originally Posted by logan_paul View Post
    I'm the only one who doesn't understand your point.
    In my example above, the heat is being rejected at a much lower temperature.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

    Did you really need the " If you were a real tech " ??

  7. #33
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    First heard about the Dick Wirz book here and can wholeheartedly recommend as well.
    Currently in the 3rd edition of print, sample chapters are available for free trial at the Google Play store.
    The entire book is also available in e-book form.
    Not my cup of tea as I prefer the printed page.

    Note about superheat, the discussion needs to be narrowed as to which superheat your cohort is measuring.
    At the evaporator outlet, or at the compressor inlet?

  8. #34
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    Quote Originally Posted by jackfowler View Post
    Refrigeration is the process of cooling a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is rejected at a higher temperature).
    I think it's referring to the condensing temperature being higher than ambient and heat is rejected.

  9. #35
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    Quote Originally Posted by BBeerme View Post
    My book is almost 40 years old. Interestingly enough, I pulled it out a week ago, then put it back this morning.

    Attachment 809362
    BBeerme, my copy of that book is Copyrighted in 1968. Purchased in 1969. Modern Refrigeration & AC,,,
    Gleng, my copy of that book is Copyrighted 1963. Purchased in 1972. Doolins Bible,,,
    Timebuilder, my copy of that book is Copyrighted 2010, Purchased in 2016..Commercial Refrigeration for AC Techs,,,,

    All a Good Read!

  10. #36
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    30 degree superheat is high for almost all applications even at the compressor it is at the max most comp manufactures want to see.

    It IS possible that it is ok for some situations, however it makes no difference what so ever because you can't use ONLY subcooling and superheat to evaluate a refrigeration system or its performance.

    A simple example using the OP number of 30 sh. It makes a huge difference what your delta is over the evaporator, if you have 10 degrees then the sh may simply be a high load on the coil, if you only have 3 degrees you dont have enough refrigerant IN THE EVAPORATOR, you MIGHT not have enough or it may be somewhere else within the system.

    SC AND SH are two pieces of info, about 20 percent of the information you need to figure out what is going on.

  11. #37
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    I do triple evacuation with nitro to remove non-condensable. I did not use other methods.

  12. #38
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    Quote Originally Posted by Jon30 View Post
    I do triple evacuation with nitro to remove non-condensable. I did not use other methods.
    I thought that nitro is a non-condensable. So there has to be something more involved here.

  13. #39
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    Quote Originally Posted by Jon30 View Post
    I do triple evacuation with nitro to remove non-condensable. I did not use other methods.
    Quote Originally Posted by TechmanTerry View Post
    I thought that nitro is a non-condensable. So there has to be something more involved here.

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