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Geek Culture / Cooling thought

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General Reed
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Posted: 15th Dec 2007 03:55
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Why do amd/intel not just put a metal hollow block, with liquid nitrogen inside. would that not cool down the processor

CPU: AMD X2 6000+ 3.0ghz GFX: NVIDIA BFG Geforce 8800GTS 640MB OC-550mhz core RAM: 2048mb

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Keo C
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Posted: 15th Dec 2007 03:57
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Quote: "Why do amd/intel not just put a metal hollow block, with liquid nitrogen inside. would that not cool down the processor"

It would shatter if touched when that cold.


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bitJericho
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Posted: 15th Dec 2007 04:02
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Uh, liquid nitrogen does eventually warm up you know:o)


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n008
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Posted: 15th Dec 2007 04:02
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Quote: "Why do amd/intel not just put a metal hollow block, with liquid nitrogen inside. would that not cool down the processor"


Because liquid nitrogen boils well below room temperature?

That's like asking why people in cold areas don't just set themselves on fire when it gets in the twenties!

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bitJericho
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Posted: 15th Dec 2007 04:06
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I only wish it were the 20's up in here. It's about 2°F out here, and will be much colder as the night rolls on. I sometimes wish I could light myself on fire, but by the time I pull out the lighter it's too cold to move


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n008
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Posted: 15th Dec 2007 04:13
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Quote: "I only wish it were the 20's up in here. It's about 2°F out here, and will be much colder as the night rolls on. I sometimes wish I could light myself on fire, but by the time I pull out the lighter it's too cold to move "


Well, I had a pretty acurate representation of temprate -> cold temps. on humans vs. room temp. -> hot in processors.

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CattleRustler
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Posted: 15th Dec 2007 04:38 Edited at: 15th Dec 2007 04:38
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theyve temporarily solved the heat issue of silicon based chips - by reducing the clock speeds back into the upper 2 ghz range, and doubling the cores.

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Cash Curtis II
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Posted: 15th Dec 2007 04:52 Edited at: 15th Dec 2007 04:55
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What's surprising is that you guys don't know how liquid nitrogen cools, or how liquid cooling works in general.

Liquid nitrogen, in compressed form, is not cold. It only produces a cooling effect when it vaporizes, i.e., when it comes into contact with the atmosphere.

So, you could hook up a big tank of liquid N2 to your computer, and if it didn't shatter the entire thing it would eventually run out and you'd have to replace the canister. Over and over and over, and a single canister isn't cheap.

The same principle applies to a normal fridge - freon, or similar coolants, are allowed to vaporize and thus cool the box. The gas is then re-compressed into liquid form, then the cycle is repeated. The problem with transforming liquid N2 back into liquid form is that it takes massive pressure and an extremely expensive system. In a standard rig the N2 would all just leak out, the molecule is tiny compared with a Freon molecule.

In short, it's a silly idea. It's like my 6 year old's idea that a fan can make air in space.


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ionstream
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Posted: 15th Dec 2007 05:00
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Quote: "Liquid nitrogen, in compressed form, is not cold. It only produces a cooling effect when it vaporizes, i.e., when it comes into contact with the atmosphere."


It can either be highly pressurized and warm or extremely cold and not pressurized. It has nothing to do with reacting with the atmosphere.

That's not as bad as you think you said.
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Cash Curtis II
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Posted: 15th Dec 2007 05:02
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Yes it does, atmospheric pressure.


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dark coder
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Posted: 15th Dec 2007 08:59
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Quote: "Liquid nitrogen, in compressed form, is not cold."


-196°C is quite cold, and what do you mean in compressed form? What would be the purpose of compressing liquid nitrogen be? Doing so would only take extreme amounts of power and a very strong storage device to contain the pressure. If you attempted to place a block filled with liquid nitrogen on your CPU then(assuming it's just a hollow block filled with the stuff) very quickly the block would rupture spilling the liquid everywhere followed by a huge mist as it all boils away.

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Cash Curtis II
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Posted: 15th Dec 2007 11:57 Edited at: 15th Dec 2007 12:01
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By compressed I mean in the liquid state at an average temperature - compressed gas. You can't compress a liquid anyway, that's not what I meant. The liquid is not cold, the drop in temperature occurs when it vaporizes.


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hessiess
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Posted: 15th Dec 2007 12:25
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http://www.youtube.com/watch?v=X04IbmrkaN8

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Arkheii
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Posted: 15th Dec 2007 15:04 Edited at: 15th Dec 2007 15:17
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http://en.wikipedia.org/wiki/Liquid_nitrogen

Quote: "Despite its reputation, liquid nitrogen's efficiency as a coolant is reduced by the fact that it boils immediately on contact with warmer object, enveloping it in insulating nitrogen gas."


Quote: "Since the liquid to gas expansion ratio of this substance is 1:694, a tremendous amount of force can be generated when liquid nitrogen boils off for whatever reasons. In a well-known accident in 2006 at Texas A&M University, the pressure-relief devices of a tank of liquid nitrogen were sealed with brass plugs. As a result, the tank failed catastrophically, and exploded. The force of the explosion was sufficient to propel the tank through the floor/ceiling immediately above it."


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David R
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Posted: 15th Dec 2007 16:16
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Quote: "when it vaporizes, i.e., when it comes into contact with the atmosphere."


You mean when it boils, right? The whole reason (lqd.) Nitrogen acts like that is because it has a very low boiling point


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n008
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Posted: 15th Dec 2007 16:21
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Quote: "You mean when it boils, right? The whole reason (lqd.) Nitrogen acts like that is because it has a very low boiling point"


Yea... That's not got much to do with the atmosphere. If it was -200+ (Fahrenheit) outisde, liquid nitrogen would just be liquid nitrogen. Any warmer and it boils. Making the cloud of the gas appear.

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David R
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Posted: 15th Dec 2007 16:27
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This is ultimately irrelevant though - the whole problem is that semiconductors would break/not function at such a temperature anyway.

Not to mention that the changing of temperature (during manufacture, or between usage etc.) would likely cause stress damage to the components and what-not.


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dark coder
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Posted: 15th Dec 2007 18:14
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Quote: "The liquid is not cold, the drop in temperature occurs when it vaporizes."


What do you mean? For nitrogen to be a liquid it must be at least -196°C, if it wasn't cold as you say i.e. 10°C then it would be a gas thus expand greatly and break its containment. Because such cold items are usually placed within containment surrounded by near vacuum it may lead you to believe it's not cold but this is merely because there is very little thermal conduction between the outside casing and the actual container.

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General Reed
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Posted: 15th Dec 2007 19:09
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Well im trying to overclock my 6000+, but it seems to heat up to 49 idle.

CPU: AMD X2 6000+ 3.0ghz GFX: NVIDIA BFG Geforce 8800GTS 640MB OC-550mhz core RAM: 2048mb

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Keo C
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Posted: 15th Dec 2007 19:11 Edited at: 15th Dec 2007 19:11
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It's already at 3.0Ghz. Unless it is a Digg webserver or something, you don't need more RAM or CPU power.


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demons breath
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Posted: 15th Dec 2007 19:19
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Quote: "It's like my 6 year old's idea that a fan can make air in space."


You mean that wouldn't work?

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Cash Curtis II
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Posted: 15th Dec 2007 19:52 Edited at: 15th Dec 2007 19:53
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Quote: "What do you mean? For nitrogen to be a liquid it must be at least -196°C, if it wasn't cold as you say i.e. 10°C then it would be a gas thus expand greatly and break its containment. Because such cold items are usually placed within containment surrounded by near vacuum it may lead you to believe it's not cold but this is merely because there is very little thermal conduction between the outside casing and the actual container."


Dark Coder, liquid nitrogen inside of a canister is not -196°C. It would be impossible to perpetually insulate a container like that from the atmosphere. If you could do that then freezers that never got opened wouldn't need power.

If nitrogen is cooled to -196°C then it will liquify. By the same token, if you compress the gas sufficiently then it will liquify. When you expose it to normal pressure and temperature then it will boil and all turn to nitrogen vapor. That's what makes it cold.

Have you ever noticed that any compressed liquid that turns to gas produces a cooling effect? Like I said, this is why freon and other refrigerants are used.


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dark coder
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Posted: 15th Dec 2007 20:39
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Quote: "Dark Coder, liquid nitrogen inside of a canister is not -196°C"


It is.

Nitrogen is a liquid at −210.0°C to -196°C.

Quote: "It would be impossible to perpetually insulate a container like that from the atmosphere."


As I said above, liquid nitrogen is stored in a containers which are surrounded by a partial vacuum, this means very little heat from outside of the container is being transferred to the nitrogen via thermal conduction. Thus if this container was insulated by a perfect vacuum and the nitrogen container itself was suspended above this casing(via magnetism?) then the temperature of the nitrogen would remain constant indefinitely as there is no way for the nitrogen to gain heat energy.

Quote: "If nitrogen is cooled to -196°C then it will liquify. By the same token, if you compress the gas sufficiently then it will liquify. When you expose it to normal pressure and temperature then it will boil and all turn to nitrogen vapor. That's what makes it cold."


It will turn to liquid at room temperature when compressed enough, yes. However the pressure required to do this for nitrogen is incredibly high, as well as the containment to store this pressure. It is far more efficient to store it(by far) as a liquid at -196°C at 1 bar, I highly doubt anywhere in the world liquid nitrogen is stored at room temperature, or even if it's possible with current technology.

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David R
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Posted: 15th Dec 2007 20:56 Edited at: 15th Dec 2007 20:59
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Quote: "It is.
Nitrogen is a liquid at −210.0°C to -196°C."


Although I disagree with Cash's other points, liquid N2 is actually stored frozen at -210'c. Not that it makes much difference, but just to note that it is stored so it isn't boiling inside of its own cannister

EDIT: Actually, I think it depends what it's being used for


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n008
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Posted: 15th Dec 2007 21:03 Edited at: 15th Dec 2007 21:03
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Quote: "Cash Curtis is right, so-called evaporative cooling is what makes liquid nitrogen cold.

To give an ordinary example, the gas in a lighter is liquid as well, but lighters aren't stone-cold, nor are they surrounded by a partial vacuum to keep them cold. What keeps the gas liquid is the pressure."


Semi-true.

What everyone here has totally side-stepped is that N2 BOILS at -197!!

So yes, liquid Nitrogen IS FREAKING COLD.

That's like saying water is never cold unless it is frozen!

The lack of ENERGY ("more pressure") is what keeps the liquid a liquid. This is also relative to heat.

So yes, it IS possible to store liquid N2 at more than -197, but it would only be possible at great amounts of pressure, tus more heat, thus no practicality!

Again the amount of ENERGY is what keeps the liquid liquid. Different thinks solidify and deteriorate at different temperatures!

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David R
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Posted: 15th Dec 2007 21:04
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Quote: "What everyone here has totally side-stepped is that N2 BOILS at -197!!"


-196c. No one has side-stepped it, it has been mentioned constantly throughout


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n008
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Posted: 15th Dec 2007 21:06
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Yea, and? So it's been mentioned, but you all ignored it.

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ionstream
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Posted: 15th Dec 2007 21:13 Edited at: 15th Dec 2007 21:18
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Quote: "Yes it does, atmospheric pressure."


Ah, right.

n008 is wrong, Cash is right. Nobody "ignored" the fact that the boiling temperature and liquefying temperature are the same temperature.

Consider a gas in a canister. If you were to highly compress it, it would become very hot while it's volume decreases. If you were to let the hot compressed gas cool to room temperature, it would not be especially cold. But now if you were to decompress the gas to its original volume, it would become very cold. Thats the refrigeration cycle, and nitrogen decompresses when it is released from the canister into an atmospheric pressure environment.

That's not as bad as you think you said.
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n008
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Posted: 15th Dec 2007 21:17
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That's what I said.

Unfortunately, Liquid nitro is NOT stored in pressurized containers, but ones, like dark coder said, surrounded by semi-vacuums.

I said it was possible. Cash Curtis plainly said that liquid notro is not cold. That is incorrect.

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dark coder
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Posted: 15th Dec 2007 21:27
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But you can't compare lighter fluid to nitrogen as lighter fluid can turn into a liquid(at room temperature) with very little pressure(same as the fridge example using a vapour compression cycle). The same can not be said for nitrogen, for nitrogen to become a liquid at room temperature you require an insane amount of pressure(I don't have the figures on hand) for this reason is it more efficient and far safer to store liquid nitrogen at 1bar(-196c).

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Benjamin
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Posted: 15th Dec 2007 21:28 Edited at: 15th Dec 2007 21:31
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Cash actually said compressed liquid nitrogen is not cold, which is correct. But this all depends on the pressure.

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n008
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Posted: 15th Dec 2007 21:36
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Quote: "When you expose it to normal pressure and temperature then it will boil and all turn to nitrogen vapor. That's what makes it cold."


Is wrong.

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General Reed
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Posted: 15th Dec 2007 21:59 Edited at: 15th Dec 2007 21:59
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explain in detail why not overclock a 6000+ apparently games such as alan wake require incredable amounts of processing power

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General Reed
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Posted: 15th Dec 2007 22:02
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Also what would you guys say is an acceptable under load tempreature?

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bitJericho
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Posted: 15th Dec 2007 22:03
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Well, you could damage the processor/ram/northbridge?

You shouldn't do it unless you are very comfortable with how overclocking works. That said, my P4 3.4ghz processor is over clocked to almost a 1000mhz fsb.

You can learn about the process of overclocking at overclock.net.


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bitJericho
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Posted: 15th Dec 2007 22:06
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As for temp, it depends on the processor, I dont know off hand what a 6000+ can take. You'll have to check AMD's site. I know on intel processors they publish a "thermal spec", this is how hot the processor can get before it starts to get damaged.


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Cash Curtis II
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Posted: 16th Dec 2007 01:05 Edited at: 16th Dec 2007 01:10
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@n008 -
I'm right, you're wrong. I know a lot about refrigeration, it's a subject that's interested me for a long time for some reason.

@dark coder -
A vacuum does not insulate energy. If it did then energy wouldn't travel through space. Now, the atmosphere, and any other liquid or gas or solid, can absorb and radiate heat, but heat can still radiate through space. Think about what you're saying - if a vacuum makes a 'perfect' insulator, then a refrigerator would use a vacuum space to insulate, and would perpetually keep anything inside cold provided that you didn't open it, including the air trapped inside. That's just not how that works. Heat is constantly being exachanged until equillibrium is reached.

Also, if heat couldn't radiate into a vaccum then the Earth would look like Venus.

Nitrogen in a canister is compressed. Nitrogen molecules are bigger than Oxygen molecules, so it's not that hard to store provided that the tank is solid and the valves well made. Liquid hydrogen is impossible to store with today's technology because of the size of the H2 molecule.

The cooling effect happens when a liquid turns into a vapor. This is because energy is required for the phase change. This isn't so obvious when the boiling temperature is higher, like with water, because we're forcibly applying heat to make it boil. With a compressed gas it's very obvious, in order to make the phase change it takes the heat from its surroundings.

If you compressed boiling water, it would stop boiling even though heat is still being applied. The same thing is what happens to compressed nitrogen. The catch, of course, is that if you heat the canister up then it could explode, because the pressure inside the canister will rise dramatically with increased heat.


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dark coder
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Posted: 16th Dec 2007 02:24
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Quote: "A vacuum does not insulate energy."


It insulates from thermal conduction very well, I did not say all means of energy transfer.

Quote: "If it did then energy wouldn't travel through space."


You must be talking about electromagnetic radiation, which in this situation is highly minimal.

Quote: "Now, the atmosphere, and any other liquid or gas or solid, can absorb and radiate heat, but heat can still radiate through space."


Via thermal radiation it can, but I was talking about thermal conduction.

Quote: "Think about what you're saying - if a vacuum makes a 'perfect' insulator, then a refrigerator would use a vacuum space to insulate, and would perpetually keep anything inside cold provided that you didn't open it, including the air trapped inside. That's just not how that works. Heat is constantly being exachanged until equillibrium is reached."


It may not be a perfect insulator, but we are talking about relatively low amounts of thermal energy thus the amount of electromagnetic radiation being emitted by the casing will be very low. And for the most part it would be perpetually the same temperature, other than the low amounts of electromagnetic radiation that will be transferred into the inner casing, however for the scope of liquid nitrogen storage this should be more than adequate.

Quote: "Also, if heat couldn't radiate into a vaccum[sic] then the Earth would look like Venus."


Earth(for the most part) does not lose thermal energy via thermal conduction.

Quote: "Liquid hydrogen is impossible to store with today's technology because of the size of the H2 molecule."


Last time I checked space shuttles didn't fail to take off due to their fuel leaking through containment.

Quote: "The cooling effect happens when a liquid turns into a vapor. This is because energy is required for the phase change."


No. It only appears cooler because you have the same amount of molecules occupying a larger space thus the thermal energy per set area will be less, however the total area will expand.

Quote: "The catch, of course, is that if you heat the canister up then it could explode, because the pressure inside the canister will rise dramatically with increased heat."


I'm sure the canister will explode well before the nitrogen becomes a liquid.

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Cash Curtis II
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Posted: 16th Dec 2007 02:45
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Quote: "I'm sure the canister will explode well before the nitrogen becomes a liquid."

That's the crux of your argument, but it's wrong.

If a vacuum can insulate so well, then why do refrigerators need to be plugged in? A fridge could just use the same principle that you're saying a LN2 canister uses.


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dark coder
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Because usually when I place items in a fridge they are warm and I put them in the fridge to cool down and to preserve the temperature? If it was just a pure vacuum surrounding the fridge and I did this the contents of the my fridge(provided it's cooler than my item) will cool down and eventually equalize due to thermal conduction and stay at that temperature(depending on the aforementioned thermal radiation levels of the surroundings). Most fridges are only working(i.e. removing thermal energy from the fridge's contents) when it's above a certain temperature, fridges aren't constantly on you know. If it was surrounded by a pure vacuum(thus 0 thermal conduction), once the contents of the fridge is below the desired temperature the fridge no longer requires any energy(to cool the contents). However fridges are not surrounded by vacuums as doing so is costly, increases the weight(to contain the vacuum), is risky(if containment on the vacuum broke many things could happen). Fridges themselves I'm sure are surrounded by materials that insulate very well thus making the cost to gain ratio low.

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n008
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Posted: 16th Dec 2007 03:47
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Quote: "@n008 -
I'm right, you're wrong. I know a lot about refrigeration, it's a subject that's interested me for a long time for some reason."


Ok, whatever. But saying that liquid nitrogen isn't cold? Whatever floats your boat...

Oh, and BTW, only radiation carried in light can pass through a vaccum. Just evergy gets whipped everywhere until it reaches matter. This is why a vacuum is freaking cold. Energy will not rest in itself. If what you say is true then space would be semi-bearable by now in our solar system...

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Megaton Cat
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Posted: 16th Dec 2007 03:51
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Quote: "It's like my 6 year old's idea that a fan can make air in space."


Right, next thing you're gonna tell me is that wind isn't actually caused by trees moving back and forth simultaneously?

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n008
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Posted: 16th Dec 2007 04:02
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Quote: "If a vacuum can insulate so well, then why do refrigerators need to be plugged in? A fridge could just use the same principle that you're saying a LN2 canister uses."


Let's see...

1.) A refridgerator does not need to be cooled to -200 oC?
2.) A vacuum- surrounded refridgerator is mostly impractical, and dangerous
3.) To sustain the vacuum, power would be needed anyway...

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dark coder
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Posted: 16th Dec 2007 04:24
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Quote: "Ok, whatever. But saying that liquid nitrogen isn't cold? Whatever floats your boat..."


Liquid nitrogen doesn't need to be cold, after all boiling points change with pressure, however the pressure required to alter the boiling point of nitrogen is extremely high to the point that it's not practical and lowing the temperature is more viable.

Quote: "Oh, and BTW, only radiation carried in light can pass through a vaccum."


Visible light is part of the electromagnetic spectrum which in turn is radiation, radio waves, X-Rays, Gamma-Rays etc are all forms of electromagnetic radiation, like visible light.

Furthermore anything can pass through a vacuum, even matter it's just a matter of interpretation. A vacuum after all is just a void of space which has little to no matter in it, therefore vacuum can and does have some matter, thus these stray particles are moving through a vacuum.

Quote: "Just evergy gets whipped everywhere until it reaches matter."


A single particle in a vacuum will not whip anywhere, if you were to release a gas into a vacuum then the pressure differential would cause decompression resulting in the gas spreading in all directions however.

Quote: "This is why a vacuum is freaking cold."


A vacuum is not cold, cold(in this context) implies there is matter present which has little to no thermal energy. If all of these stray particles in space had high levels of thermal energy then it would still be called a vacuum. Just because a vacuum contains little to no matter does not make it cold or warm, it's just the absence of matter thus it cannot be either.

Quote: "Energy will not rest in itself. If what you say is true then space would be semi-bearable by now in our solar system..."


Quote: "3.) To sustain the vacuum, power would be needed anyway..."


Only if your vacuum containment isn't properly sealed. If you have a gas tank(a strong one) and remove all matter from within it thus creating a vacuum, as long as you adequately seal it you won't be required to use any extra energy to sustain it.

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n008
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Posted: 16th Dec 2007 04:38
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Quote: "Only if your vacuum containment isn't properly sealed. If you have a gas tank(a strong one) and remove all matter from within it thus creating a vacuum, as long as you adequately seal it you won't be required to use any extra energy to sustain it."

Wouldn't you need some pretty heavy-duty steel to keep it from imploding?

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hyrichter
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Posted: 16th Dec 2007 06:20 Edited at: 16th Dec 2007 06:25
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Quote: "Wouldn't you need some pretty heavy-duty steel to keep it from imploding?"


Someone correct me if I'm wrong, but this is what I understand:
Atmospheric pressure is approximately 14psi (depending on elevation.) If canisters are created that easily handle hundreds and thousands of psi, it stands to reason that a properly built container shouldn't implode from simple atmospheric pressure. I mean, I've got an air compressor out in the shop that keeps it's pressure at 175 psi, and it hasn't ever threatened to explode (yet).

Anyway, I believe Cash Curtis is partially correct. Think of liquids like propane, where it's pressurised into a liquid form in the canister. Or heck, what about those cans of compressed air for cleaning computers? Haven't you ever held one of those upside down (despite the warnings) and sprayed it on something? However, my understanding is that the pressure required to pressurize nitrogen into a liquid state is far too high to be practical, thus the vacuum chamber is used.

Can't believe nobody has linked to this yet:
http://en.wikipedia.org/wiki/Liquid_nitrogen

Edit: Apparenly, Arkheii did, but I wonder how many people bothered to read about how liquid nitrogen is stored?

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Mr Z
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Posted: 16th Dec 2007 12:28 Edited at: 16th Dec 2007 12:30
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You know, I have some experiance with this. Once, in school, we visited this universety. They had liquid nitrogen, and we where supposed to experiment with them. They did not store it in compressed containers. The liquid was extemly cold. They put it in these storage things that was made out of this very strage material, which did not have an "roof". So you could even put your fingers in it if you liked (but no one of us did ). Anyway, we used it to create superconducors, or whatever it is called when an materals electrical resistance becomes non-existant. And THAT requires cold. Lol. It was funny to se magnets float in the air about those superconductors. Anyway, they told us that it was very cold and that we should treat it as boiling water... before they put it on our hands! That was quite funny, actually. I did it several times. Well, twise, at last.

Liquid nitrogen is extremly cold (not talking about compressed nitrogen now).

Quote: "A vacuum does not insulate energy. If it did then energy wouldn't travel through space. Now, the atmosphere, and any other liquid or gas or solid, can absorb and radiate heat, but heat can still radiate through space."


Well, you are right and not right. The reason energy can travel through vacume is because it is transpored by an carrier particle. In case an heat, an photon works quite well. Vacuume is, however, perfect when it comes to isolating two materals from each other, like air and liquid nitrogen. All we need is to make sure no carrier particles for heat is rediated through the vacuume, and that´s not that hard at all.

Darknes, you haunt me. If I give in, I would be an monster beyond imagining. Light, you guide me. Thanks to you, I see past the nothingness. Life, I choose to live in the light.
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