Source for this or similar heatsink

[HooRide]

I am looking to rebuild a 30A power supply I built when i was 15 into a nicer (and safer) enclosure. I really liked the wind tunnel heat sink design that the BK Precision e-load had that we saw in Dave's tear-down and looked for a source for them. Ironically, the only source was in Australia. Anything in the US so I don't have to forgo eating for a week just to pay for shipping?

http://www.jaycar.com.au/productView.asp?ID=HH8530&form=CAT2&SUBCATID=980#1

[notsob]

Do a search for something like 'aluminium extrusion heat sink', a quick look & I found Ullrich.com in Australia, who seem to have a similar profile, or for you, possibly wakefield.com in USA

[rsjsouza]

I am not sure how many transistors you have to "freeze", but I am designing a 20A 12V fixed output power supply that has two TIP36C and I am using this  CPU heatsink that I had lingering around. Given that this heatsink kept my 125W CPU at around 60°C, this will be enough in my design, considering the Vce voltage drop, the current and the thermal derating of the transistors (basically the last graph at this datasheet. 

You can find similar stuff everywhere at several price points (check this example), but always watch out the parameters above and make sure you have a good thermal connection between the devices and the heatsink.

If you are lucky whoever grabs the HS off the shelf from Newark might not realise that it’s actually two stuck together so you may get 2 for the price of one.

Very nice score!

[Monkeh]

Given that this heatsink kept my 125W CPU at around 60°C

TDP != actual power dissipation, by a long shot.

[rsjsouza]

TDP != actual power dissipation, by a long shot.

You are correct that TDP is not always equal to the maximum dissipated power of a CPU , but that depends on how the manufacturer defines it.

In my case my processor was an AMD Athlon 64 3500+ and they define it in a more "real" way than Intel (reference 1, reference 2).

One thing I noticed is that my older processor was 89W instead of 125W - that may bring me back to the drawing board... 

[free_electron]

try fisher electronics. or aavid thermalloy. they have tunnels and will cut to length even for 1 piece

[Harvs]

TDP != actual power dissipation, by a long shot.

You are correct that TDP is not always equal to the maximum dissipated power of a CPU , but that depends on how the manufacturer defines it.

In my case my processor was an AMD Athlon 64 3500+ and they define it in a more "real" way than Intel (reference 1, reference 2).

One thing I noticed is that my older processor was 89W instead of 125W - that may bring me back to the drawing board... 

I've put 120W into a very similar looking Thermaltake cooler, as a CC load.  It handled it fine and kept the mosfet case temps (two of) at around 65oC.  Just don't let the fan stop, I thought I'd see what happened...  At that power level, it only took a few seconds for the temps to skyrocket.

For me, it was just too difficult mounting them though.

[rsjsouza]

For me, it was just too difficult mounting them though.

Yep, that is the annoying part. I intend to do a threaded hole instead of using a nut and a bolt.

[Monkeh]

For me, it was just too difficult mounting them though.

Yep, that is the annoying part. I intend to do a threaded hole instead of using a nut and a bolt.

Mm, threaded hole into a heatpipe, that sounds like a good move.

[SeanB]

Just miss the pipes, not exactly hard to look at the 2 ends and avoid the piece. I just use the non heatpiped versions, and with low power you do not need a fan, though it will be good at over 15W.

[Monkeh]

Just miss the pipes, not exactly hard to look at the 2 ends and avoid the piece.

Really? These look kinda hard to avoid.



Welcome to modern heatsinks.

[Monkeh]

I am skeptical about these heatpipe style heatsink designs. Not because I have any actual facts but because they seamed to develop in the desktop PC world where transparent sided cases and internal LED lighting also thrive. It just seems like another variant of the audiophoolery religion but for overclockers. Which came first, needlessly (?) decorative heatsinks or the windows and lighting to show them off.

They don't charge more for it, the basic physics back the design up, and the performance backs it up too.

The other thing I really hate is people who hijack a thread and attempt to spin it off in a completely new direction.

You must hate yourself.

[alm]

I am skeptical about these heatpipe style heatsink designs. Not because I have any actual facts but because they seamed to develop in the desktop PC world where transparent sided cases and internal LED lighting also thrive. It just seems like another variant of the audiophoolery religion but for overclockers. Which came first, needlessly (?) decorative heatsinks or the windows and lighting to show them off.

Heat pipes were first introduced in notebooks (and before that in non-electronics applications). But since these don't typically have transparent cases, you wouldn't normally see them .

Another possible example might be perforated brake discs on bicycles. If my car doesn't need a perforated disc then does a bicycle? Are the holes necessary for improved braking performance? Or just decoration or weight saving, and hence just another excuse to engage in self delusional religious debates.

Weight savings are a real thing. Ask a mechanical engineer about the difference between rotating mass and static mass and their effect on performance. From memory, 1 kg of extra mass on the wheels is equivalent to 5 kg of extra static mass due to rotational inertia (don't remember under which conditions). In the case of suspension, unsprung mass vs sprung mass enters into the picture.

[Tube_Dude]

Heat pipes were first introduced in notebooks (and before that in non-electronics applications)...

Sony used them (with freon) back in 1979/1980, in the TA-F55 amplifier...

http://seventiesstereo.blogspot.pt/2010/09/sony-ta-f55-integrated-amp.html

[Tube_Dude]

Thanks Tube_Dude. Why am I not surprised to learn that they were first used in an audio amplifier?
I read the blurb on the "Vintage Knob" link and can't help wondering why such an interesting breakthrough wasn't retained on all future models. .

Maybe it was more expensive to make than the normal extruded heatsinks, and don't add nothing in the "sound quality" department.

At the time some more brand marks have used it in one or two models, but almost all had let it down.

At the end of the day, just another case of technological exercise, so well suited for the marketing department brochures... 

[T4P]

Using freon is a good idea in heat piping, you know, a air-conditioner depends on the coolant's rapid evaporation to cool the surrounding air down and they use pipes to transfer the coolant, so in heatsinks they are called "heat pipes" because all they do is pipe heat with a coolant (What's the name? I can't remember it)
But in most heatsinks that aren't too high power they just use a liquid that doesn't evaporate i think


The reason AMD was able to efficiently pipe 300W of heat around their dual-GPU monster is due to something called a "vapor-chamber" (which essentially is a heat pipe filled with very volatile liquid (I mean something like the stuff they use for aircons?) without going over 80C in such a form factor

[SeanB]

Depends on the temperature and the distance as to what you use. For a PC cooler you can use methanol and make sure the charge is put into the system after a deep vacuum is pulled. You can then run at up to 70C with good results. Otherwise you will need a high pressure and use R600 ( propane) or R134A as the liquid. All depends on how much pressure you are willing to have in the sealed system as to the refrigerant you use. If you use a steel block you can get good results with R717 ( anhydrous ammonia) as the transfer medium.

Heat pipes are basically an equilibrium at the hot side, the pressure adjusting to keep the liquid there boiling, and the vapour condensing at the cold side, then wicking back along the internal wick material ( a mesh layer on the wall that holds liquid by capillary action) to be evaporated again.

[Harvs]

I was sceptical about using CPU coolers with heatpipes until I tried it.

With a standard aluminium plate and fin heatsink roughly double the dimentions of the CPU cooler, the MOSFETs being driven at 60W each would quickly overheat.  Even using arctic silver transfer compound.  I found that even with the ~10mm plate on the heatsink, the thermal resistance of the aluminum caused significant localised heating around the mosfets.

So with a few people on this forum's recommendation I tried the CPU cooler, very similar to the one in this post.  The difference was night and day.  The effective heat transfer away from a concentrated area is awesome.

To this day I'm still thinking about easy ways to clamp the MOSFETs in place.  Current idea having seen mikeselectricstuff's video would be to make up some PCB plates.