Zalman CNPS9500AT Heat Pipes

[tvl]

Several weeks back there was a post regarding the Zalman heat pipes. The individual wanted to know if the pipes were filled with a liquid and if it was important to mount the cooler in an upright position. I also became curious, especially concerning the mounting position, since my cooler is in a tower and the cooler is not mounted vertically.

I e-mailed Zalman and here is their response (hope this is helpful to others also):

Dear Valued Customer,

We would like to first thank you for your use of our CNPS9500 AT.

For the answers to your questions, please refer to the following:

1) The heat pipes of ZALMAN coolers are indeed filled with coolant. However, we cannot disclose the exact information about the coolant.

2) It is also true that the CNPS9500 AT will function better if it is positioned in an upright position (vertically with the base down) than when it is positioned horizontally. However, the difference in thermal performance resulting from the orientation (vertical/horizontal) of the cooler is minimal, and we believe that it will hardly make a difference even if you lay the tower on its side.

Therefore you do not have to lay down the tower on its side because it will not make great difference in thermal performance by doing so.

Hope this answer your question, and please feel free to ask any further questions.

Best Regards,

Support/ZALMAN

 

[bront]

most heat pipes now have wicks that allow for circulation regardless of orientation. (That sounds like a policical campaign speech)

 

[smedlin]

Hmp, that's actually kinda intersting.

 

[clue69less]

I e-mailed Zalman and here is their response: (snips)

2) It is also true that the CNPS9500 AT will function better if it is positioned in an upright position (vertically with the base down) than when it is positioned horizontally. However, the difference in thermal performance resulting from the orientation (vertical/horizontal) of the cooler is minimal, and we believe that it will hardly make a difference even if you lay the tower on its side.

Therefore you do not have to lay down the tower on its side because it will not make great difference in thermal performance by doing so.

A while back, I was searching the literature on heat pipes and found an article about pipe orientation. The article claimed that orientation was important as the heat flux through the pipe neared the upper limit. Once the pipe is pushed beyond it's limit, it's ability to conduct heat efficiently goes into the crapper. That would be real bad for your CPU.

 

[wun911]

Its good to know that it will work upright or sidways...

I thought that heat was just transferd from the CPU via conduction (the metal itself) and convection (the liquid inside the pipe). And that these two principles of heat transfer do not rely on gravity.

Anybody out there tempted to cut up a zalman heat pipe to see whats inside? ??

 

[Grimmy]

I asked this question awhile back. I guess this is the 1st time I've seen the answer to this question.

Interesting to know.

I did have a feeling that it used some kind of liquid that would turn to vapor to help transfer heat. So it does make logical sense that it would work best when it sits upwrite.

But seeing they say its minimal difference, kinda defeats the purpose of using fuild in the heat pipes... but owell, nice to know anyways.

 

[linux_0]

Its good to know that it will work upright or sidways...

I thought that heat was just transferd from the CPU via conduction (the metal itself) and convection (the liquid inside the pipe). And that these two principles of heat transfer do not rely on gravity.

Anybody out there tempted to cut up a zalman heat pipe to see whats inside? ??

I would not recommend it.

The chemical coolant may be very hazardous.

 

[clue69less]

Anybody out there tempted to cut up a zalman heat pipe to see whats inside? ??

I would not recommend it.

The chemical coolant may be very hazardous.

It could be a hazardous compound, that's true. But if you look at the literature, most heat pipes running in the temperature range of CPUs, GPUs, etc., use water, acetone, ethanol, etc. And, yes, I'm tempted but not enough to trash my HSF, so I just surf the literature for my tech fix.

 

[chuckshissle]

Most heatpipes on HSF assemblies contains a type of ammonia. It works by transfering the heat to the coolest side (the radiator side) and condenses releasing the heat and the fluid goes back through the wick to the heatsink and repeats the cycle.

 

[clue69less]

Most heatpipes on HSF assemblies contains a type of ammonia. It works by transfering the heat to the coolest side (the radiator side) and condenses releasing the heat and the fluid goes back through the wick to the heatsink and repeats the cycle.

Most? Not according to the literature I've read. In the first place, you have to qualify the working heat range of a device and the required heat flux. That will get you into a range of liquids that will work. It is very application-specific but ammonia is by no means a universal heat pipe liquid.

 

[linux_0]

Most heat pipes on HSF assemblies contains a type of ammonia. It works by transferring the heat to the coolest side (the radiator side) and condenses releasing the heat and the fluid goes back through the wick to the heatsink and repeats the cycle.

Most? Not according to the literature I've read. In the first place, you have to qualify the working heat range of a device and the required heat flux. That will get you into a range of liquids that will work. It is very application-specific but ammonia is by no means a universal heat pipe liquid.


Water, ethanol and mercury are sometimes used in heat pipes.

Mercury is very dangerous and "industrial" ethanol ( aka denatured alcohol ) is also highly flammable and toxic to humans and animals. So it's not the stuff you want to be playing with.

Acetone and other substances that might be used in heat pipes are not exactly safe either, so I wouldn't mess with them.

 

[clue69less]

Most? Not according to the literature I've read. In the first place, you have to qualify the working heat range of a device and the required heat flux. That will get you into a range of liquids that will work. It is very application-specific but ammonia is by no means a universal heat pipe liquid.

Water, ethanol and mercury are sometimes used in heat pipes.

Mercury is very dangerous and "industrial" ethanol ( aka denatured alcohol ) is also highly flammable and toxic to humans and animals. So it's not the stuff you want to be playing with.

Acetone and other substances that might be used in heat pipes are not exactly safe either, so I wouldn't mess with them.

From what I've read, use of mercury in heat pipes is pretty rare these days and I can't find anyone in the PC cooling industry that will admit to using it. Yes, all alcohols are toxic, ethanol being the least toxic among them, but remember, we're talking very little liquid in a CPU HSF and the contaminants in denatured ethanol are there at pretty low levels. If you were to cut open a HSF that had denatured ethanol in it and got a few drops on your hands, it would not be a toxicity issue whatsoever. I doubt there would be a flammability issue either. It's not like we're talking about having a large amount of liquid in there. Among the substances you list, mercury is by far the greatest health risk in the perspective of this thread (cutting open a HSF heat pipe to see what's inside). I'm a chemist and I personally wouldn't be the least bit afraid to do it, but I'd do it in a safe manner with proper protective gear, in a hood, etc.

 

[linux_0]

Most? Not according to the literature I've read. In the first place, you have to qualify the working heat range of a device and the required heat flux. That will get you into a range of liquids that will work. It is very application-specific but ammonia is by no means a universal heat pipe liquid.

Water, ethanol and mercury are sometimes used in heat pipes.

Mercury is very dangerous and "industrial" ethanol ( aka denatured alcohol ) is also highly flammable and toxic to humans and animals. So it's not the stuff you want to be playing with.

Acetone and other substances that might be used in heat pipes are not exactly safe either, so I wouldn't mess with them.

From what I've read, use of mercury in heat pipes is pretty rare these days and I can't find anyone in the PC cooling industry that will admit to using it. Yes, all alcohols are toxic, ethanol being the least toxic among them, but remember, we're talking very little liquid in a CPU HSF and the contaminants in denatured ethanol are there at pretty low levels. If you were to cut open a HSF that had denatured ethanol in it and got a few drops on your hands, it would not be a toxicity issue whatsoever. I doubt there would be a flammability issue either. It's not like we're talking about having a large amount of liquid in there. Among the substances you list, mercury is by far the greatest health risk in the perspective of this thread (cutting open a HSF heat pipe to see what's inside). I'm a chemist and I personally wouldn't be the least bit afraid to do it, but I'd do it in a safe manner with proper protective gear, in a hood, etc.


You're right, but it's better to play it safe and not perform any surgery because you don't know what you'll find when you cut up the heat pipe.

Some coolants are flammable so the sparks from your dremel may start a small fire.

The contents may also be under pressure depending on the temperature of the heat pipe and might be released when you cut or break it open.

The contents may not be extremely toxic but they may be toxic enough to cause health problems or even cause serious harm to children or animals in the vicinity of your surgical table.

Pure ethanol / ethyl alcohol / grain alcohol is toxic but not quite as toxic as the additives mixed with it to turn it into denatured alcohol / industrial ethanol such as methanol, pyridine, benzene and others.

 

[clue69less]

You're right, but it's better to play it safe and not perform any surgery because you don't know what you'll find when you cut up the heat pipe.

That's not a very adventurous approach.

Some coolants are flammable so the sparks from your dremel may start a small fire.

Dremel? There are ways to avoid sparks when cutting.

The contents may also be under pressure depending on the temperature of the heat pipe and might be released when you cut or break it open.

Probably so. So you'd want to be ready for that possibility.

The contents may not be extremely toxic but they may be toxic enough to cause health problems or even cause serious harm to children or animals in the vicinity of your surgical table.

Kids aren't allowed around my mod table. And the only animals allowed are those that are expendable. Seriously, this is a trivial risk to avoid.

Pure ethanol / ethyl alcohol / grain alcohol is toxic but not quite as toxic as the additives mixed with it to turn it into denatured alcohol / industrial ethanol such as methanol, pyridine, benzene and others.

Sure, I already mentioned that - but look at the levels present and the liquid volume in a single Zalman HSF. Unless you plan to drink the contents of about 1,000 Zalman HSF's, this isn't an issue. I thought we were talking about opening one up to see what's inside, not drinking it.

I'm not advocating cutting up your Zalman HSF. What a waste! But if I needed to, I could absolutely, positively guarantee that I could do it in a safe manner. I've done much more dangerous operations hundreds of times and miraculously managed to escape alive. Safety training and the right tools are the keys.

 

[Grimmy]

Has anyone tried running the 9500 in both postions? (Upright/Sideways in a tower case)

Only info I'd be interested in, is the room temp, case temp, and CPU temp differences, that the technolgoy in cooling works with gravity playing a role.

Heh, I don't care what is inside of the heat pipe. I'd like to know what the min difference is in running it with the force of gravity working with it vs not working at all.

I'm guessing there prolly won't be any difference, especially if the room temp is at or above 80 F.

After talking with a guy who had a Scythe KATANA (heatpipe with a 70 degree tilt 80+F room temp) who said it didn't have a difference when place sideways or upright, I wonder if there would be more of an effect if the room was cooler then 75F. (68-70F room temp was the range I was thinking of to test).

Other then that, I fail to see how the liquid helps any cooling at all if it can't go back and forth from the base to the top. I just think its just part of a marketing scheme, as well as making the product look kewl.

 

[clue69less]

Has anyone tried running the 9500 in both postions? (Upright/Sideways in a tower case)

Funny you mention that... I recently bought some components to do just such a test. Rather than use a case, my plan is to use a precise thermocouple-controlled heater and measure how much current the heater draws as a measure of how much heat the HSF can remove. So an easy experiment is to look at HSFs in different orientations. It's one of a few things a I are fiddling with in my spare time to try to develop HSF tests that don't require a functional CPU. One of the hard parts is making sure the inlet air is always at constant temp. The basement laboratory is becoming increasingly cluttered. If I can get this test bench running right, I'll tell y'all about it.

 

[chuckshissle]

Sorry what I mean is Acetone not Ammonia. :lol:

 

[clue69less]

Sorry what I mean is Acetone not Ammonia. :lol:

OK, that makes sense. I admit, I was wondering what temp range ammonia worked in. I worked with ammonia quite a bit in school - really nasty stuff when it's pure - like knock you on your butt nasty. Acetone smells sweet by comparison.

 

[linux_0]

Sorry what I mean is Acetone not Ammonia. :lol:

OK, that makes sense. I admit, I was wondering what temp range ammonia worked in. I worked with ammonia quite a bit in school - really nasty stuff when it's pure - like knock you on your butt nasty. Acetone smells sweet by comparison.


Ammonia is toxic and corrosive.

Acetone is very flammable ( vapor is explosive ) is an irritant as well as a carcinogen and it breaks down many plastics.

 

[chuckshissle]

Yeah, what I mean was Acetone and this has been discussed here about a month ago. It's used becuase of it's properties and able to boil at low temps. I've read some articles about it and how it's applied to HSF assembly and can't seem to find it.

 

[clue69less]

Ammonia is toxic and corrosive.

Acetone is very flammable ( vapor is explosive ) is an irritant as well as a carcinogen and it breaks down many plastics.

That's all true, but I've known plant operators that washed their hands daily in acetone throughout their 40 year careers. Without dieing of cancer. I've used it a bunch and try to keep it away from skin contact, but I'm not too worried about it. In general, organic solvents are not the best things to bathe in.

 

[wun911]

Has anyone tried running the 9500 in both postions? (Upright/Sideways in a tower case)

Funny you mention that... I recently bought some components to do just such a test. Rather than use a case, my plan is to use a precise thermocouple-controlled heater and measure how much current the heater draws as a measure of how much heat the HSF can remove. So an easy experiment is to look at HSFs in different orientations. It's one of a few things a I are fiddling with in my spare time to try to develop HSF tests that don't require a functional CPU. One of the hard parts is making sure the inlet air is always at constant temp. The basement laboratory is becoming increasingly cluttered. If I can get this test bench running right, I'll tell y'all about it.

Run this experiment by me again please Materials Methods etc etc. Please include the literature you have read: scientific journals with references etc etc or even links to web pages with hear say?

My hypothesis is that the HSF is just a pipe that conducts heat and it is solid in nature (Has no liquid in the midle) (may be holow with just air). Seeming nobody has actually cut one of these 9500s up and drained the liquid out.... Nobody can disprove or prove my hoypthesis. Hearsay is hearsay untill I see it with my own eyes.

IF the 9500 works both sideways, upsidedown, upright etc... Wouldnt that just suport my hypothesis... "that there is infact no liquids inside these pipes"?

Or would it sugest that gravity does not play a role in heat transfer as I mentioned earlier?

 

[clue69less]

Has anyone tried running the 9500 in both postions? (Upright/Sideways in a tower case)

Funny you mention that... I recently bought some components to do just such a test. Rather than use a case, my plan is to use a precise thermocouple-controlled heater and measure how much current the heater draws as a measure of how much heat the HSF can remove. So an easy experiment is to look at HSFs in different orientations. It's one of a few things a I are fiddling with in my spare time to try to develop HSF tests that don't require a functional CPU. One of the hard parts is making sure the inlet air is always at constant temp. The basement laboratory is becoming increasingly cluttered. If I can get this test bench running right, I'll tell y'all about it.

Run this experiment by me again please Materials Methods etc etc. Please include the literature you have read: scientific journals with references etc etc or even links to web pages with hear say?

My hypothesis is that the HSF is just a pipe that conducts heat and it is solid in nature (Has no liquid in the midle) (may be holow with just air). Seeming nobody has actually cut one of these 9500s up and drained the liquid out.... Nobody can disprove or prove my hoypthesis. Hearsay is hearsay untill I see it with my own eyes.

IF the 9500 works both sideways, upsidedown, upright etc... Wouldnt that just suport my hypothesis... "that there is infact no liquids inside these pipes"?

Or would it sugest that gravity does not play a role in heat transfer as I mentioned earlier?

If I thought you were really serious, I'd share some literature with you. If you doubt that a heap pipe is hollow, all you need to do is take a pair of pliers and partially crush a heat pipe. Then try that with a piece of solid copper rod. I wish I could take you more seriously. The literature on heat pipes is extensive - Google it out.

 

[Grimmy]

My hypothesis is that the HSF is just a pipe that conducts heat and it is solid in nature (Has no liquid in the midle) (may be holow with just air). Seeming nobody has actually cut one of these 9500s up and drained the liquid out.... Nobody can disprove or prove my hoypthesis. Hearsay is hearsay untill I see it with my own eyes.

IF the 9500 works both sideways, upsidedown, upright etc... Wouldnt that just suport my hypothesis... "that there is infact no liquids inside these pipes"?

Or would it sugest that gravity does not play a role in heat transfer as I mentioned earlier?

Errr... read the very 1st post or the guy that started the thread.

Ummm.. or if your too lazy to do that, let me do a short quote:

1) The heat pipes of ZALMAN coolers are indeed filled with coolant. However, we cannot disclose the exact information about the coolant.

 

[rsmart]

Aren't most nail varnish removers acetone based?