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Thread: Liquid N2? for cooling?

  1. #16
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    Carbon dioxide has no liquid form. At high enough temperature and low enough pressure it sublimates, that is, it changes directly from a solid (dry ice) to a gaseous form. To build a refrigeration unit you need a non-acidic and non-flammable gas such as chloroflouromethane (R-22) or tetraflouroethane (R-134A) that will liquify at a suitable pressure in a condenser and give you the temperature drop you need across an expansion orfice. The refrigerant must be molecularly compatibile with the oil used to lubricate the internal components of the compressor. This assures a stable and long lasting refrigeration unit.

  2. #17
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    You're asking for trouble if you use liquid nitrogen. Dunk a CPU in it (which is effectively what happens when you first turn the system on) and the rapid temperature change could shatter the CPU, or at least cause internal stresses that will weaken the CPU over time.

    Immersing the whole computer in mineral oil is just crazy, I've seen that example and if he EVER wanted to move his computer he'd be ****ed. I regularly move mine around for LAN games and such so that sort of thing isn't an option. The only possibility for me if air wasn't enough would be some kind of water cooling. If necessary I could carry the reservoir and pump around and fill it up once I got to my destination. but I don't need the speed that badly

  3. #18
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    my water cooler worked well kept the cpu at room temp no condensation no leaks, I did try mineral oil instead of water and the pump wouldnt pump the thicker oil with enough volume to keep the heatsink cool. building a water cooler is simply a matter of enclosing your heatsink and putting connectors on for tubing, I used on in and two out that way the pressure inside the cooler is less and so are the chances for leaks. I used a vantek slot 1 cooler which is shaped perfectly because the center fins over the cpu slug are shorter than the outside ones so all I had to do is take some abs plastic screw it to the heatsink, screws wedge between the fins and seal is up with epoxy drill on hole on one end and two holes on the other for the tubing connectors and that was it. I have a cel 400 that wont run at 500 with a standard heatsink with the water and the peltier that I am currently using it is perfectly stable. I was hoping the peltier would get me to 600 but it didnt. The peltier introduced a whole new set of problems. as long as you make sure you seal the cooler well I recomend using one, less case heat, lower cpu temp, what more can you ask for. I think mineral oil would work you just have to have a pump capable of pumping it. I used a small aquarium pump and it doesnt build enough pressure to pump through the small tubing I was using.

    ------------------

  4. #19
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    Mar 1999
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    You guys are insane!

  5. #20
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    Aug 1999
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    1. Liquid nitrogen is to cold to use, unless done correctly.
    2. CO2 is in a liquid form when under pressure. As it drops in pressure it phase changes into a vapor. As it phase changes it expands rapidly and gets very cold.
    3. Water coolers and peltiers are great I agree. But they cannot get my cpu below -70F

    4. If you type "heat transfer" into yahoo, you will find a company that makes a liquid that can be chilled to lower temps without freezing.

    I use N2O on cars to make them faster and I WILL use it on my puter to make it faster!!!!!!!!

  6. #21
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    Have you ever wondered WHY N2O makes your car faster? It's an oxidizer. Which means that if you have any heat source (ie. cigarette, gas stove, kerosene heater, etc) you run the risk of fire or explosion in an open system. Rogue is right. To my knowlege, CO2 has no liquid form. Granted, I'm no expert. It's been several years since my last chem or physics course.
    To use N2O to cool a processor seems silly when there are sooo many other alternatives.
    Every dark cloud has a silver lining, but lightning kills hundreds of idiots every year who are looking for it.

  7. #22
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    Aug 1999
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    Take a bottle of N2O and hold a match or small open flame in front of it and open the bottle. You will be disappointed to find that flame is no more. Unless coupled with a fuel of some sort such as oil, gas, grease and brought to a temperature of 572F (where the oxygen is released from the nitrogen) N2O will not burn or ignite. Also, CO2 does have a liquid form. CO2 and N2O have very similar properties.

  8. #23
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    CheifDruid, he is right about the liquid CO2. I did some checking and at sufficient PSI (several hundered to over 1000 depending on the temperature) CO2 will indeed liquify. It doesn't work well as a refrigerant though because if you deviate from this pressure/temperature range at all, you will once again have either a gas or a solid (dry ice). It is interesting information though and if you want to read more about it this link will take you to an article that explains the fundamentals of CO2 matter states at various pressures and temperatures:

    http://members.aol.com/co2clean/snowform.htm

  9. #24
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    Thanx Rogue, I stand corrected about the CO2 thing. But, JF, N2O is just a little more flammable that you might think. Granted, hold ing a bottle of Nitros to a match and opening it WOULD put the match out. Have you ever tried to light a propane torch with a match? It also will blow the match out. Granted, these are 2 different types of reactions, combustion and oxididation. But blowing a match out is not necessarilly a chemical property. It has more to do with the pressure at which the gas is leaving the nozzle of the bottle. Now, take the same bottle of N2O and apply it to, say, the hot end of a cigarette. I think you'll see more than just the cigarette being blown out.
    I'm not trying to be a smarta$$. Im truly not. I'm just trying to say that there are better, more cost effective, and safer ways to cool processors to very low temps.
    Shane
    Every dark cloud has a silver lining, but lightning kills hundreds of idiots every year who are looking for it.

  10. #25
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    Aug 1999
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    Windsor,Ontario,Canada
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    As far as using cooling systems which use water, one has to be very carefull. Water although not a good long range conductor, will completely fry your computer if current gets passed over shorter distances. Also even if the condensation doesn't form on a current carrying element, you will get corrosion. Water likes to take the electrons of other molecules (i.e. causes things to rust; yet as a liquid there are too many random collisions for it to be conductive). As far as recompressing N2, good luck, you would be wasting so much energy that you might as well buy an Alpha workstation and forget about the whole deal. In order to efficiently recool (through pressure) your gas AT THE SAME RATE you are using it, you need some very expensive and high tech equip.
    The best bet would probably be some kind of non-conductive oil that can be pumped around the chip. The inevitable leaks will not completely destroy your computer, just make it very messy.

  11. #26
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    Aug 1999
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    I love hearing your guys respones. Any comments you have are not taken in the wrong way. I am still somewhat new to computer overclocking but have played around with N2O and CO2 for much of my past 10 years. In order for the n2o and co2 to get cold it must pahse change to a vapor. As it phase changes it get very cold. Once it does that it gets the box (enclosed heatsink) -127F. I ran a .014 orifice just before the box in order to get a higher pressure drop into the box. I just ran a hose from the box to the outside to release that vapor. As long as that box does not get oil or grease in it or 572F, there should be no problem with a fire hazard. I am going to use CO2 soon, because C02 has a higher expansion rate therefore 10LB will go further. Also CO2 is will not support combustion. I just need a cyrogenic compressor now to pressurize the vapor back into a liquid for reuse. The recycling is still in the works right now but the box does work. If I had a camera or scanner I would offer some pics. My goal is a cpu that under load runs at -90F (approx -70C). Thanks for all your comments.

  12. #27
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    You are going to have to have one hell of a compressor and heat exchanger (condenser) to produce the necessary pressure increase and temperature drop to reliquify that Nitrous Oxide.

    As stated earlier, you should probably stay away from Carbon Dioxide as your choice for a closed refrigeration system. It's not flexible or stable enough to be a viable solution. Why don't you try R290, otherwise known as PROPANE. Just make sure you seal your lines up good and you won't have to worry about it blowing up on you. Propane is highly efficient for sub-zero refrigeration and extremely stable in the presence of standard mineral refrigerant oil. It's also cheap. It has been outlawed as a refrigerant in the US but is still popular in Europe.

  13. #28
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    OOOOH, Is that all? You say a cryogenic compressor? hehehe, jk. That falls under one of the things that makes N2 cooling not cost effective. For around $50- $75 I can build a watercooler/Peltier combo, and for a few dollars more, I can cascade the peltiers for even lower temps. Total cost is still around $100. take care ppl...

    Shane
    Every dark cloud has a silver lining, but lightning kills hundreds of idiots every year who are looking for it.

  14. #29
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    Aug 1999
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    I'm just curious what the interest is in getting the chips below -40 which is what I think I read was the optimum conditions for this type of equipment.

  15. #30
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    Aug 1999
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    Crossville, TN, US
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    I have an idea that may or may not work but from reading some of the posts here I think the solution isn't any one thing but a combination of several.
    1st make a custom radiator style colling system for all areas pron to major heat.
    2nd run a mineral oil threw them to circulate the oil and disipate the heat
    3rd construct a pumping system (ie. fishtank pump, windshield washer pump, ect...) and attach CO2 to the outside of the system to add extra cooling.
    i play paintball and in this sport you use Nitrogen or CO2 as the air source while the nitro dosen't get cold and is better for paintball the CO2 will freeze your gun after only a few shots if you could create a way to circulate the oil intn an expation cahmber from paintball the CO2 would be cooling the oil as it passed threw and would if not drasticaly reduce the temp at least take it down some probably better that air but who knows.
    4th ignore the fact that i cant spell

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