1. This forum section is a read-only archive which contains old newsgroup posts. If you wish to post a query, please do so in one of our main forum sections (here). This way you will get a faster, better response from the members on Motherboard Point.

Pumping Liquid Nitrogen

Discussion in 'Overclocking' started by Guy Macon, Dec 20, 2007.

  1. Guy Macon

    Guy Macon Guest

    I have been offered a small (about the size of a water
    cooler) liquid nitrogen generator at an attractive
    price. It generates four and a half liters per day,
    using a gravity feed to keep a half liter dewar filled.

    I want to pump the liquid nitrogen into a hole drilled
    into the heatsinks of the CPU and GPU of a gaming PC
    so I can overclock them farther than otherwise possible.
    (This is for a a "just for fun" personal project, not
    for work).

    My question is how best to pump the liquid nitrogen.
    In the past I have worked with big dewars and let them
    self-pressurize with a relief valve on top and a feed
    tube going to the bottom -- sort of like an aerosol
    can. This doesn't look feasible in this case; the back
    pressure seems like it will back up the gravity feed.
    I think I need a small pump that can take the cold and
    not add too much heat to the liquid nitrogen. Any ideas?

    BTW, I have seven old 500 MHz. Pentium 3 systems that
    are ready to be scrapped that I will be doing my
    initial experiments on before deciding whether to
    risk a more modern PC.
     
    Guy Macon, Dec 20, 2007
    #1
    1. Advertisements

  2. Guy Macon

    amdx Guest

    Let me be the first to say, "that's going to be cool." :)
    Mike
     
    amdx, Dec 20, 2007
    #2
    1. Advertisements

  3. It would be easier to deal with the boiloff gas - it's still at 77K.
    Do you actually need the LN2?
     
    Dirk Bruere at NeoPax, Dec 20, 2007
    #3
  4. Guy Macon

    D from BC Guest

    The only thing that comes to mind is pumps used for liquid fuel
    rockets.

    D from BC
     
    D from BC, Dec 20, 2007
    #4
  5. Guy Macon

    D from BC Guest


    CPU cooling with liquid nitrogen


    D from BC
     
    D from BC, Dec 20, 2007
    #5
  6. What's the temperature spec on the CPU you will be using? Odds are that
    it won't deal with LN2 temperatures well.

    Consider the heat capacity of LN2 (include the heat of vaporization)
    compared to that of H2O. For the complexity of what you propose to do,
    LN2 won't buy you much more than a good heat exchanger/radiator setup.

    Also, keep in mind that in an enclosed space (your mom's basement? ;-))
    the nitrogen gas will displace air and asphyxiate the user if not
    properly ventilated.
     
    Paul Hovnanian P.E., Dec 20, 2007
    #6
  7. Guy Macon

    Phil Weldon Guest

    'Guy Macon' wrote, in part:
    | I have been offered a small (about the size of a water
    | cooler) liquid nitrogen generator at an attractive
    | price. It generates four and a half liters per day,
    | using a gravity feed to keep a half liter dewar filled.
    _____

    You could just Google a search string that includes [ overclocking CPU
    liquid Nitrogen ] and get over 94,000 hits. Most (if not all) these Rube
    Goldberg devices just build a tank around the CPU heatsink, fill the tank
    with liquid Nitrogen and let it boil off as it may. For actually pumping
    liquid nitrogen you could contact NASA for a few tips... especially safety
    tips.

    Taking a flyer with a Pentium III is hardly worth the effort.

    One possibility for a more or less continuously operating cooler would be to
    use the boil-off of liquid nitrogen to chill an anti-freeze mixture
    (propylene glycol & water ~ 50:50 should be good to below - 40) that you
    could then pump through a more or less stock CPU water block.

    Phil Weldon

    "Guy Macon" <http://www.guymacon.com/> wrote in message
    |
    |
    |
    |
    | I want to pump the liquid nitrogen into a hole drilled
    | into the heatsinks of the CPU and GPU of a gaming PC
    | so I can overclock them farther than otherwise possible.
    | (This is for a a "just for fun" personal project, not
    | for work).
    |
    | My question is how best to pump the liquid nitrogen.
    | In the past I have worked with big dewars and let them
    | self-pressurize with a relief valve on top and a feed
    | tube going to the bottom -- sort of like an aerosol
    | can. This doesn't look feasible in this case; the back
    | pressure seems like it will back up the gravity feed.
    | I think I need a small pump that can take the cold and
    | not add too much heat to the liquid nitrogen. Any ideas?
    |
    | BTW, I have seven old 500 MHz. Pentium 3 systems that
    | are ready to be scrapped that I will be doing my
    | initial experiments on before deciding whether to
    | risk a more modern PC.
    |
    | --
    | Guy Macon
    | <http://www.guymacon.com/>
    |
     
    Phil Weldon, Dec 20, 2007
    #7
  8. Guy Macon

    Paul Guest

    There is a whole forum devoted to LN2 and dry ice here.
    Maybe someone here will have an answer.

    http://www.xtremesystems.org/forums/forumdisplay.php?f=156

    Paul
     
    Paul, Dec 20, 2007
    #8
  9. That's wonderful; how are you going to deal with frost? Where's this
    water gonna go when it melts?
     
    a7yvm109gf5d1, Dec 20, 2007
    #9
  10. Guy Macon

    MooseFET Guest

    You can use a simple piston pump for the actual pumping. The motor
    should be connected via a very long non conducting rod.

    The construction of the pump can use Teflon parts where things need to
    slide and silicone parts where a little springiness is needed.

    The idea, however is quite insane. The thermal stress will break
    things in the computer.
     
    MooseFET, Dec 20, 2007
    #10
  11. Guy Macon

    default Guest

    You could be shooting yourself in the foot. I think the self
    pressuring with a dip tube in the flask is the way to go. Back
    pressure? Where is that coming from? Plan to regulate the boil off
    at the outlet of the Pentium heat sink?

    The gas is much less dense than liquid to it should get through the
    heat sink without much back pressure .

    The foot wound - check the low temp specs on the Pentium before you go
    all out on this. Transistor gain goes way down at cryogenic
    temperatures.
    --
     
    default, Dec 20, 2007
    #11
  12. Guy Macon

    Guy Macon Guest

    Yup. The latent heat of evaporation for Nitrogen is 198.3 Joules
    per gram at one atmosphere, while the the specific heat capacity
    for nitrogen is only 1.006 Joules per gram per degree Kelvin.
    Also, liquids conduct heat far better than gasses.

    I don't have an uploadable cooling curve for nitrogen
    at hand, but take a look at the cooling curve for water:
    [ http://www.physchem.co.za/Heat/Graphics/Heat42.gif ].
    The portion of the curve labled D shows that the energy
    needed to go from 99.99 degrees C to 100.01 degrees C
    is much larger than from 0.01 degrees C to 99.99
    degrees C. This is typical of boiling liquids.
     
    Guy Macon, Dec 20, 2007
    #12
  13. Guy Macon

    Guy Macon Guest

    Others have done it without any problems. Semiconductors as a
    rule do not mind LN2 temperatures as long as you avoid thermal
    shock and icing. Besides, overclockers pretty much expect to
    lose a few if they push the envelope.
    It will buy me minus 196 degrees, and others who have tried it have
    reported a stable system with a 3GHz. CPU overclocked to 5GHz.
    Nope. that's for systems with a *source* of nitrogen. A nitrogen
    generator takes as much out of the room air as the boiling nitrogen
    puts back in. (I would ventalate it anyway, but for the opposite
    reason; to avoid any Oxygen concentration around the generator)
     
    Guy Macon, Dec 20, 2007
    #13
  14. Guy Macon

    Guy Macon Guest

    A: Because it messes up the order in which people normally read text.

    Q: Why is top-posting such a bad thing?

    A: Top-posting.

    Q: What is the most annoying thing on Usenet?

    You are talking to the person who taught the cryogenic
    safety classes for Parker Hannifin on the space shuttle
    17 inch disconnect project -- under contract with NASA.
    You prefer I ruin a few Core Duos while I experiment?
    I don't want minus 40. I want minus 196.
     
    Guy Macon, Dec 20, 2007
    #14
  15. Guy Macon

    Guy Macon Guest

    Frost comes from condensation. Condensation comes from
    moisture in the air (humidity). Boiling liquid Nitrogen
    produces a gas that has no moisture in it -- it is
    completely dry -- and will fill the enclosure if I make
    it so that all fans recirculate instead on exhausting.

    I will have to worry about the outside of the case
    dripping, though. I wouldn't want it to drip on to
    the internal circuitry.
     
    Guy Macon, Dec 20, 2007
    #15
  16. Guy Macon

    Guy Macon Guest

    A slow cool down is needed to avoid thermal shock.
     
    Guy Macon, Dec 20, 2007
    #16
  17. Guy Macon

    ~misfit~ Guest

    Somewhere on teh intarweb "Guy Macon" typed:
    Ohhh! Original.

    You come into our house asking advice and act like this? Good luck with
    that.
    And you're asking your questions here because all those contacts you made
    are ob holiday?
    Sure, with the money you made from a morning's teaching cryogenic safety
    classes you could ruin a few Core Quads. After all, you can afford a liquid
    nitrogen generator, what's a few hundred bucks worth of CPUs? Trying it with
    a PIII is like learning to drag-race in a pedal-car.
    Well Mr. Cryo-teacher, be sure to let us know how it works out for you. Or
    not.
     
    ~misfit~, Dec 20, 2007
    #17
  18. Guy Macon

    Guy Macon Guest

    Experience designing the 17 inch wide valve that connects the
    external tank to the space shuttle doesn't apply much to the
    problem of finding a small, cheap pump for less than a liter
    per hour of liquid nitrogen.
    The word "taught" is past tense. I no longer work for Parker.
    The Jamboree Blvd. plant closed down quite some time ago.
    If I was thinking of trying something that could burn out my
    expensive drag racer, I might very well try it on a few pedal
    cars first. Even if I could afford to destroy multiple race
    cars.
    "Arguing with anonymous strangers on the Internet is a sucker's
    game because they almost always turn out to be -- or to be
    indistinguishable from -- self-righteous sixteen-year-olds
    possessing infinite amounts of free time."
    -Neil Stephenson, _Cryptonomicon_

    *plonk*
     
    Guy Macon, Dec 20, 2007
    #18
  19. Guy Macon

    Rich Grise Guest

    Notwithstanding the "it's _TOO_ cold!" warnings, if you own your own
    house, you could use plain ol' gravity feed - just put the generator
    on the floor above the comp, with a very tall dewar between.

    Of course, that depends on whether modifying the house is cheaper
    than a(an?) LN2 pump. ;-)

    Good Luck!
    Rich
     
    Rich Grise, Dec 20, 2007
    #19
  20. Guy Macon

    redbelly Guest

    Yup, gravity feed was exactly my thinking as I read through this
    thread. Let me just add:

    Keep the liquid nitrogen BELOW eyelevel. Think about not only spills,
    but drops spattering about. (Imagine grease or water in a hot frying
    pan. That's what liquid nitrogen does when it hits "hot" room
    temperature objects).

    Mark

    p.s. that being said, I will mention that I violated the "eye level
    rule" back in grad school. The main point is to be careful while
    still having fun.
     
    redbelly, Dec 20, 2007
    #20
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.