Life span of HSFs?

[goobee]

Heat pipes are filled with distilled water or other fluids. I imagine if nothing leaks, a HSF should last for years. Thoughts?

[Tsavo]

No clue.

I did read on a website a few years ago wherein they opened the heat pipes on a stack of coolers and none of them had any phase change material in them.

Makes me wonder.

[Slugbait]

I've had only two heatsink fans die. The first (back in the 90s) was due to a couple of years of dust buildup. The other (two years ago) was due to heat: the wife's case wasn't getting decent airflow, so the fan was running full-speed all the time and burned itself out...it lasted almost two years before dying.

So yeah, an HSF should last for years.

[goobee]

Originally Posted by Tsavo

No clue.

I did read on a website a few years ago wherein they opened the heat pipes on a stack of coolers and none of them had any phase change material in them.

Makes me wonder.

Really? I'd like to see that. Got a link?

[VirtualLarry]

My HyperTX2 units have lasted a good 5 years or more. Thankfully.

[jumpncrash]

depending on the size, rotational speed and quality of the bearings, fans can last either a long time or not long at all.

A few years back there was a wave of 40mm northbridge fans that kept dying.

But given enough abuse (dirt, dust, smoke, cat fur) fans can and do die, however they usually don't die without giving some signs first, so most people don't need to worry, they'll hear the fan die long before it actually kicks the bucket.

[Blain]

Originally Posted by Tsavo

I did read on a website a few years ago wherein they opened the heat pipes on a stack of coolers and none of them had any phase change material in them.

Makes me wonder.

Hmm... I'm not surprised, because heat pipes aren't "phase change" devices.
They use capillary action in a thermal cycle to transfer heat from one spot to another.

[Tsavo]

Originally Posted by Blain

Hmm... I'm not surprised, because heat pipes aren't "phase change" devices.
They use capillary action in a thermal cycle to transfer heat from one spot to another.

The point, which you clearly missed, was that there was no material of any sort in the tubes.

[Blain]

If they had no liquid at all, they were defective or fake.

[Wall Street]

You need to keep in mind that only a very small amount of material (a single drop) is needed. Also, a lot of it is gas at any given time and it is kept in a vacuum, so I wouldn't be surprised if when they broke through the wall of the heatpipe, most of the material immediately evaporated into the air (invisible water vapor) and was ejected from the pipe. It is in there though. Don't expect to see a drop come out if you saw your heatpipe, because if the heatpipe was full of liquid it wouldn't work (how would the gas get from one end to the other if there was too much liquid), just like it wouldn't work if empty.

"Phase change" is an accurate way to describe a heatpipe. It relies on evaporating liquid to gas at the heat source and condensing gas to liquid at the fins.

[WoodButcher]

Originally Posted by Wall Street

You need to keep in mind that only a very small amount of material (a single drop) is needed. Also, a lot of it is gas at any given time and it is kept in a vacuum, so I wouldn't be surprised if when they broke through the wall of the heatpipe, most of the material immediately evaporated into the air (invisible water vapor) and was ejected from the pipe. It is in there though. Don't expect to see a drop come out if you saw your heatpipe, because if the heatpipe was full of liquid it wouldn't work (how would the gas get from one end to the other if there was too much liquid), just like it wouldn't work if empty.

"Phase change" is an accurate way to describe a heatpipe. It relies on evaporating liquid to gas at the heat source and condensing gas to liquid at the fins.

Thank you.
This is a horse that has been beaten so long it isn't fit for glue.
Those that cut open heatpipes in search of magic juice are truly on a fool's errand.

[Captain Howdy]

Originally Posted by Tsavo

No clue.

I did read on a website a few years ago wherein they opened the heat pipes on a stack of coolers and none of them had any phase change material in them.

Makes me wonder.

Makes me wonder if the website you are reading knows anything about thermodynamics, but other than that I think I know what was going on in their scenario. (Hint: phase change cooling involves differences in pressures that our naked atmosphere does not necessarily agree with)

[Sheep221]

If you don't count the fan and thermal compound, the metal heat sink is virtually indestructible.

[aigomorla]

thats because whatever gas was inside the pipes that was at liquid state turned into gas and evap'd the moment they cut open the pipe.

They wouldnt use a raw liquid inside the pipe because it would overshoot the effiiency range.

Instead they would use a gas which had a smaller boiling and liquid point delta to maximize effiency at the set PSI inside each pipe.

And they wont see a big gas leak when they puncture the pipe because very little is inside it... again, the pipe doesn't need to be filled with the gas.

A heat pipe is like a mini phase change which works in ambient settings, and doesnt require a compressor to condense the gas back into liquid.

[Eureka]

I thought it's just water but at such low pressures that it boils at a lower temperature than usual.