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Heatpipes what is best - vertical or horizontal orientation?

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  • Heatsinks
  • Cooling
  • Overclocking
Last response: in Overclocking
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August 28, 2006 4:33:01 PM

This may seem like a stupid question but in my mind it must factor into the cooling efficiency. Tower cases are the norm for most people but some website published benchmarks are done without mounting the motherboard into a case.

In my understanding of how heatpipes work there is some liquid in the pipes-the pipes are not filled completely. The liquid in the pipes get hot from the heat of the processor and naturally heat rises, condensation occurs with the pipes and the cooler liquid goed to the bottom to cool the CPU.

If the heatpipe cooler is mounted in a tower isn't the liquid concentrated in the base of the pipes and not oriented toward the surface of the CPU where the heat transfre will be the most efficient? NOW, if the tower case were on its side, or the motherboard were in a desktop style case. The liquid in the heatpipes would be oriented in such a way that the liquid would be concentrated toward the base of the CPU. This would seemingly make the heatpipe concept more effective as a cooler.

Tha Zalman 9500 has a circulature curvature that may circumvent this problem. Maybe that is why it is effective as a cooler. But what about those coolers whose heatpipes are perpendicular to the motherboard?

Is there anything I am missing? Are my concepts of heatpipes off base?

Thanks

More about : heatpipes vertical horizontal orientation

August 28, 2006 6:07:18 PM

Heatsinks also have a sort of "wick" inside which means that when the liquid boils at the base of the heatpipe and then condenses at the top of the heatpipe that it's wicked back to the base of the heatpipe to do it's thing. Of course it would be best to use the heatsink in a desktop orientation but the difference would be minimal.
August 29, 2006 1:57:38 PM

Quote:
Heatsinks also have a sort of "wick" inside which means that when the liquid boils at the base of the heatpipe and then condenses at the top of the heatpipe that it's wicked back to the base of the heatpipe to do it's thing. Of course it would be best to use the heatsink in a desktop orientation but the difference would be minimal.


As he mentioned most heatpipes have wick kind of material. But not all. There are some cheaper heatpipes that do not have a wick type of material inside. For the most part you don't see these being used in PC's. But be careful when looking and no-name brands with heatpipes. They may not have wicks and may cause problems in a tower case.
Zalman makes excelent coolers and all of there products are top notch.

Zalman's are OK. But a bit showy and not quite as good as some other brands of heatsink. Thermalright or Scythe would be better and in some cases cheaper.
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August 29, 2006 3:04:56 PM

The only type I would be looking at would be namebrands. Zalman, Thermalright, Thermaltake, (Sythe is non-existant in Austin) but brands and models that have proven themselves via reviews and benchmarks(PLURAL). I ahve not used stock for a long time.

I have purchased an E6400 for a computer build that will only do financial charts on 6 monitors I may not need a third party cooler for it as from what I have ben seeing it is fast as a stock setup and highly overclockable on stock air.

But this was a question that has bugged me for a while now. Wick or not it still seems that the totally efficiency is compromised if the CPU cooler is not oriented properly. I guess I need to see a benchmark to convince me otherwise. I have not seen an answer I can sink my teeth into
August 29, 2006 3:11:34 PM

Quote:
The only type I would be looking at would be namebrands. Zalman, Thermalright, Thermaltake, (Sythe is non-existant in Austin) but brands and models that have proven themselves via reviews and benchmarks(PLURAL). I ahve not used stock for a long time.

I have purchased an E6400 for a computer build that will only do financial charts on 6 monitors I may not need a third party cooler for it as from what I have ben seeing it is fast as a stock setup and highly overclockable on stock air.

But this was a question that has bugged me for a while now. Wick or not it still seems that the totally efficiency is compromised if the CPU cooler is not oriented properly. I guess I need to see a benchmark to convince me otherwise. I have not seen an answer I can sink my teeth into


Go with a Thermalright SI-120 or Ultra-120. As an added bonus the SI-120 will cool the VRM on your mobo and the components around the CPU socket.
August 29, 2006 3:51:43 PM

hcforde, orientation of your heat pipes won't make any difference in the real world. Heat pipe function is driven by vapor pressure and temperature differential in a small pipe. The working fluid will go from where it's hot to where it's cooled without any help from gravity.

Heat pipes are very effective. Now that we're coming into a new generation of efficient CPUs heat pipes will be all that's needed. GPUs are a different story; these are becoming ever more power-hungry, and hotter so they need more effective heat rejection techniques.
August 30, 2006 8:43:29 AM

A 'wick' you say....

"orientation doesnt matter" you say

Not all heat pipes have a wick in my opnion....

AND orientation does matter!

Because my MB is mounted into a Lian Li and thus the MB is upside down!

Now my NB and SB are so dam hot you cant touch em!
(P5N332 SLI SE)

How could this be possible???

Because there is no liquid under the NB or SB because there is no wick or not enough liquid!

The pipes being in a vertical upsided down postion now have all the liquid so dam far away from my NB and SB... they literally cook

How could this happen you ask...

Dont ask me ask Asus, they say heat pipes work in any orientation....

What have I done to solve the problem?

Water cooled both my NB and SB....
August 30, 2006 2:43:08 PM

When I first read this thread, none of the answers satisfied me, either. But I researched it (thanks for the starter links here) and I'm siding with the "no difference camp" if there is a wicking material present. Here's my humble opinion:

You might have images of Christmas bubble lights, liquid always on the bottom, gas on the top, but it's not this way when wicking material is present. Liquid flows through the wicking material, along the the wall of the pipe, from condensation point to vaporization point. Gasses flow in the empty cavity in the center of the pipe from the vapor point to condensation point.

The cooler mfg (should) charge the pipe with the right amount of liquid to keep the wick wet (and the inside wall of the pipe) the entire length of the pipe, but with little or no excess so as not to impede gas flow.

There is not enough room for convection currents to form on this small scale. To get convection currents, you would need enough volume so that some parts of the vapor become much cooler or hotter than the surrounding vapor. Then Boyle's law kicks in, gas expands and becomes less dense, and gravity allows the cold, dense gas to fall. If the system is charged properly, the vapor never heats much past the boiling point (the wick would have to be dry) and any cooling causes it to condense - which happens at the vapor/wicking interface.

Some links indicate that distilled water is used in heat pipes, so I got curious and pulled out my thermodynamics text. If the mfg charges the heat pipe to 3% of atmospheric pressure (3.17 kPa vs. 101 kPa), water will vaporize at 25C (room temperature). In order to dissipate 100W, only 40 milligrams of water needs to be vaporized and condensed.
September 7, 2006 12:41:03 AM

I read an article by a company that designs heatpipes professionally. Orientation was a major factor to them. Don't think they were involved in the computer industry. There's did not have the fins with a big fan either so that is the difference. A guy from asus told me the same thing concerning the ASUS Silent Square. The effect is with the heatpipes and the fan moving air across the fins. As long as that occurs you are safe. But a small efficiency factor is lost and it has to do with the level of the fluid in the heatpipes and the orientation of the pipes. Some designs are better than others. Made sense
September 7, 2006 2:03:05 AM

Same story with Asus M2N-E. My Northbridge went from painfully hot to just very warm when I turned my case upside down. So I bought a new case.

Some heat pipes have a wicking material, they are more expensive. Some don't, they are cheaper.

I could easily believe that Asus tech support consists of overworked, underpaid people whose native language is not English. Someone like that could easily confuse an orientation independent CPU heat pipe with a very orientation dependent mobo heat pipe.
September 9, 2006 7:59:47 AM

If you have a name brand HSF then orientation does not matter. I personally would go thermalright then zalman. The xp-120 is very cheap if your mobo is compatible.
September 9, 2006 8:57:42 AM

I find heatpiped coolers can be a little bit of a let down when you get them.
Because the idle temp isn't as good as you'd hope for, but they never seem to get hotter than whatever temp they're "stuck" at, not like normal ones that just keep increasing at load..
September 9, 2006 9:58:05 AM

I agree, they don't seem to be as efective at lower temperatures, but as the temps increase they seem to just get better and better.
http://www.techpowerup.com/reviews/Zalman/CNPS-9500LED/... (heatpipes vs water (admittedly they're not great water coolers...))

I've got a Zalman CNPS-9500, and it's mounted in my tower case horizontally. I tried laying my case down on my desk expecting the temps to drop a little... and nothing, concluding that the orientation didn't make any difference.
September 10, 2006 1:12:41 AM

Here is the input from the "pro's". The only difference I can still find is that the computer related heatpipes have active(fans) cooling. These that they are designing seem not to. They address it directly and it is important but it seems like the CPU cooling guys seem to be in a different league.

http://www.heatsink-guide.com/content.php?content=heatp...

http://www.enertron-inc.com/enertron-products/heat-pipe...

These are from other sites
Originally Posted by Neoseeker
Some users speculate that the orientation of the Heatpipe could affect its performance, given the theory behind the heat pipe this is actually not a bad assumption. In fact, for industrial applications, the design and orientation of a heatpipe would be very specific to maximize performance. But in a CPU or video card cooler, the impact may or may not be as significant.

What we've found at Neoseeker during our reviews is that whether a heatpipe based cooler is standing upright, or standing on its side, the cooling performance difference is less than 1 degree Celsius - so in our real world testing that sort of orientation difference does not seem be a huge factor. Temperature differences resulting from orientation were slight and are likely the result of variations in the test environment.

Originally Posted by The Heatsink Guide
Vertical orientation required - In our simple model heat pipe, the working fluid simply drips back to the heat source. It is quite obvious that this design will only work in vertical orientation. To overcome this limitation, commercially available heat pipes do not rely on gravity alone to move the liquid back to the heat source; they take advantage of capillary action. The inside of the heat pipe tube is filled with a capillary structure, often referred to as wick.

Seems like heatpipes on CPU's is not an issue with quality units. On motherboards where the components are colled by a pipe there is an issue with orientation. So I guess I am not the only one with this question. Bought some ram cheap 2gig ddr2-4200 $100 infenion(aeneon) overclocks to 375 easily on stock temp 60C with C2D E6400.

So I bought an ASUS Silent Square HSF because it looked like the Tuniq Tower(it had the fan inside) but was unimpressed. It did not put out enough to breeze to feel at idle. So I guess I will get a Zalman CNPS9500AT. Considering Bigwater SE or 745 but my motherboard (P5WDG2-WS PRO) components won't get any cooling. Since this machine will run 24/6 I want the components as cool as possible


BTW, wasn't Coolermaster the first to intro heatpipes to the CPU cooling world? They seem to be left far behind the technlogy curve. There is an understanding in the business world. The first company out with a product is usually not the ones that make the most money on it.
September 11, 2006 3:31:21 AM

I only wish I could turn my PC case on its side.... but it has water cooling, and my res is kinda small. (not enough water to the pump when case is on its side)

I only WISH the heat pipes on my P5N32 SLI Deluxe SE MB would work in its upside down orientation with my Lian Li case..... Hrmz what a sweet setup that would be..... (well it will work and it is sweet for about 10min before it starts to cook)

I really didnt want to sell or give away my lian li just so I could run this MB... (both worth about the same in value)

To the dude that reckons that brands you trust will have good heat pipes that work in all orientations...... Is Asus a crap enough brand for you??? Is that better or worse than zalman?

Imagine a heat pipe that is almost a foot long and runs almost the full lenght of your MB...... but its only half filled with liquid!!!! And has no wick!!!! OMG!!!! I wonder is horizontal better or vertical?????? Hrmz let me think now......
!