cooling questions

[xwrench3]

so i just came from amazon where i was looking at cpu coolers. and a few questions crossed my mind.

1) why is there so much use of copper in them? does not aluminum dissipate heat faster than copper?

2) has anyone done a study, and rated these by heat removal capacity? in my mind, there should be a standard thermal rating for each and every cooler.

3) heat pipes, are these for real? or just a gimmick to sell coolers?

4) and if they are for real, are they filled with something to help pull heat away from the cpu?

[paprikman]

7 minutes ago, xwrench3 said:

so i just came from amazon where i was looking at cpu coolers. and a few questions crossed my mind.

1) why is there so much use of copper in them? does not aluminum dissipate heat faster than copper?

2) has anyone done a study, and rated these by heat removal capacity? in my mind, there should be a standard thermal rating for each and every cooler.

3) heat pipes, are these for real? or just a gimmick to sell coolers?

4) and if they are for real, are they filled with something to help pull heat away from the cpu?

Heat pipe is a great technology: a metallic pipe with metallic sponge inside of it, with condenced liquid (low pressure environment). When this liquid is heated, it evaporates and moves to the coolest part of pipe (where radiator is located) and cools down, turns back into liquid and goes back. This technology was a way better solution than suggested 'magnetohydrodynamic pumps', especially in space.

[ChrisCross]

10 minutes ago, xwrench3 said:

so i just came from amazon where i was looking at cpu coolers. and a few questions crossed my mind.

1) why is there so much use of copper in them? does not aluminum dissipate heat faster than copper?

2) has anyone done a study, and rated these by heat removal capacity? in my mind, there should be a standard thermal rating for each and every cooler.

3) heat pipes, are these for real? or just a gimmick to sell coolers?

4) and if they are for real, are they filled with something to help pull heat away from the cpu?

yeah heatpipes are a real thing. if you go for a higher-end model your looking at vapor chamber.

but the most important thing of a cooler is the fan!

[Ryoutarou97]

58 minutes ago, xwrench3 said:

so i just came from amazon where i was looking at cpu coolers. and a few questions crossed my mind.

1) why is there so much use of copper in them? does not aluminum dissipate heat faster than copper?

2) has anyone done a study, and rated these by heat removal capacity? in my mind, there should be a standard thermal rating for each and every cooler.

3) heat pipes, are these for real? or just a gimmick to sell coolers?

4) and if they are for real, are they filled with something to help pull heat away from the cpu?

1. IIRC aluminum to air is a bit faster than copper to air, but heat moves faster through copper than it does aluminum.

2. Nope. What are you going to measure it at? Full fan speed? Half speed? On top of that it depends on the TDP of the chip under it. A 95w chip is going to give off more heat and remain at a higher temperature than a 65w chip. Actually, now that I think about it, maybe a graph with TDP on the x axis and temperature on the y would work with 3 curves for fractional (half or so for an acoustic benchmark and to prevent insanely loud high RPM fans being abused for better ratings) speed, full speed, and an alternate fan to measure the cooler's passive dissipation ability. That said, you would still need a small and scientifically precise precise hotplate and someone to do the testing and standardised Thermal paste application methods and... ugh. 

3, 4. Answered above.

[LogicalDrm]

1. Copper conducts heat best. Aluminum dissipates it faster. Thats why best coolers have copper pipes and aluminum fins.

2. Kinda. I mean there's no one rating, because it wouldn't be standard. You get way different result with different CPUs, cases and ambient temps. You have reviews from most of coolers and can do comparison between several tested ones. Reviewers don't change testbench hardware so often and some even retest most common coolers with new hardware. Thats best source besides user experience.

3. Yes they are real. Even CM's "vapor chambers".

4. Heatpipes are filled with liquid which turn into gas when heated. Gas tranfers heat to end of pipes and cools back to liquid. Which again moves back to hotter part of cooler.

[xwrench3]

i did not know that copper moves heat faster. that is interesting.  is there any kind of problems caused by using 2 different metals  (like what happens with steel and aluminum) ? of course, even if there was, it would likely be more than 10 years before any significant amount of corrosion would take place. and few systems stay together as is for that amount of time.

 

i know that a heat transfer rating would have to be done by a mega institution or maybe a large scale scientific university. it would just be nice to have a fair way of real comparison between different coolers.  something like "xyz" cooler is 75% efficient with a 90 watt cpu @ 200 cfm @ 30 degrees c.  while "abc" cooler is 82% efficient. i think most of us know that every individual situation is different. same goes with home heating, but they have managed to put a standard on furnaces and air conditioners. i guess it really boils down to who would foot the bill, to do such research, AND if the manufacturers would be willing to go along with the standard.

 

the gas charge in the heat pipe idea is neat. having zero scientific training (after 7th grade science class), i have zero knowledge of liquid - gas properties.

 

as a mechanic, i know how liquid cooling works.  what i do not know is what the liquid computers use for liquid. is it straight distilled water? or is there some kind of anti corrosion mix in it? since they stay relatively cool, i assume they do not use pressure?

[WoodenMarker]

On 5/6/2016 at 9:43 AM, xwrench3 said:

i know that a heat transfer rating would have to be done by a mega institution or maybe a large scale scientific university. it would just be nice to have a fair way of real comparison between different coolers.  something like "xyz" cooler is 75% efficient with a 90 watt cpu @ 200 cfm @ 30 degrees c.  while "abc" cooler is 82% efficient. i think most of us know that every individual situation is different. same goes with home heating, but they have managed to put a standard on furnaces and air conditioners. i guess it really boils down to who would foot the bill, to do such research, AND if the manufacturers would be willing to go along with the standard.

How well a heatsink performs usually has more to do with the heatpipe design and how well it mounts than the metals used. 

How well metal transfers heat can be found on wikipedia and calculated with a bit of math. 

[LogicalDrm]

14 hours ago, xwrench3 said:

i did not know that copper moves heat faster. that is interesting.  is there any kind of problems caused by using 2 different metals  (like what happens with steel and aluminum) ? of course, even if there was, it would likely be more than 10 years before any significant amount of corrosion would take place. and few systems stay together as is for that amount of time.

 

Since there isn't anything which would cause chemical reaction going on, you don't see anything in 20+ years. Corrosion or rusting is a thing with moisture. But that will happen faster to other components which are using plain copper or brass with contact surfaces. If you recall Linus talking about mixing metals in his SYW water cooling build, its all about water acting as reactive chemical compound.

 

14 hours ago, xwrench3 said:

as a mechanic, i know how liquid cooling works.  what i do not know is what the liquid computers use for liquid. is it straight distilled water? or is there some kind of anti corrosion mix in it? since they stay relatively cool, i assume they do not use pressure?

 

It can be distilled water. Most of the time its mix as you said provided by companies specializing for WC gear. You will need anti-corrosive agent also. Depending on liquid it may need to be added later or its already in there. I don't really understand what you mean by pressure in this sense? Water cooling uses pumps to move liquid around the loop.

[xwrench3]

in i.c. (internal combustion) engines, the cooling system is pressurized due to higher heat (simplified), and the ever present possibility of boiling the fluid. pressure increases the resistance to boiling. once the fluid starts to boil, cooling pretty much goes out the window so to speak. as the air pockets interrupt the ability to transfer heat. plus it pushes coolant out of the system, reducing pressure, which only makes matters worse.